《有机化学》课程教学资源（教材文献，英文版）Glossary

GLOSSARY Absolute configuration(Section 7.5): The three-dimensional Activating substituent (Sections 12.10 and 12.12): A group rrangement of atoms or groups at a stereogenic center. that when present in place of a hydrogen causes a particular Acetal(Section 17.8): Product of the reaction of an aldehyde or reaction to occur faster. Term is most often applied to a ketone with two moles of an alcohol according to the substituents that increase the rate of electrophilic aromatic Active site(Section 27. 20): The region of an enzyme at which the substrate is bound. RCR′+2R"OH→>RCR′+H,O Acylation(Section 12.7 and Chapter 20): Reaction in which an acyl group becomes attached to some structural unit in a molecule. Examples include the Friedel-Erafts acylation and the conversion of amines to amides Acetoacetic ester synthesis(Section 21.6): A synthetic method Acyl chloride(Sections 2.3 and 20.1 ) Compound of the type for the preparation of ketones in which alkylation of the enolate of ethyl acetoacetate RCCI CCHCOCH_CH3 R may be alkyl or aryl. Acyl group(Sections 12.7 and 20. 1): The group the key carbon-earbon bond-forming step Acetyl coenzyme A (Section 26.1): A thiol ester abbreviated as R may be alkyl or aryl. that act source of acetyl groups in biosynthetic Acylium ion ( Section 12.7): The cation R-C Acetylene (S 1. 18 and 9.1): The simplest alkyne, HC≡CH is converted to another Achiral (Section 7. 1): Opposite of chiral. An achiral object is Addition(Section 6.1): Reaction in which a reagent X-Y ble on its mirror image. adds to a multiple bond so that x becomes attached to one Acid(Section 4.6): According to the arrhenius definition,a f the carbons of the multiple bond and Y to the other. substance that ionizes in water to produce protons. Accord 1, 2 Addition (Section 10.10): Addition of reagents of the type ing to the bronsted-towry definition, a substance that do X-Y to conjugated dienes in which X and Y add to adja- nates a proton to some other substance. According to the cent doubly bonded carbons Lewis definition, an electron-pair acceptor. Acid anhydride (Sections 2.3 and 20. 1): Compound of the type R2C=CH-CH=CR2 R2C-CH—CH=CR RCOCR 1. 4 Addition (Section 10.10): Addition of reagents of the type Both r groups are usually the same, although they need not X-Y to conjugated dienes in which X and Y add to the ter Acid dissociation constant Ka (Section 4.6): Equilibrium con- stant for dissociation of an acid R2C=CH—CH=CR2 R2C-CH=CH—CR2 H[A-] THAJ Addition-elimination mechanism (Section 23.6 ): Two-stage In G-1 Forward Main Menu TOC Study Guide Toc Student OLCMHHE Website

G-1 GLOSSARY Absolute configuration (Section 7.5): The three-dimensional arrangement of atoms or groups at a stereogenic center. Acetal (Section 17.8): Product of the reaction of an aldehyde or a ketone with two moles of an alcohol according to the equation Acetoacetic ester synthesis (Section 21.6): A synthetic method for the preparation of ketones in which alkylation of the enolate of ethyl acetoacetate is the key carbon—carbon bond-forming step. Acetyl coenzyme A (Section 26.1): A thiol ester abbreviated as that acts as the source of acetyl groups in biosynthetic processes involving acetate. Acetylene (Sections 1.18 and 9.1): The simplest alkyne, HCPCH. Achiral (Section 7.1): Opposite of chiral. An achiral object is superimposable on its mirror image. Acid (Section 4.6): According to the Arrhenius definition, a substance that ionizes in water to produce protons. Accord￾ing to the Brønsted—Lowry definition, a substance that do￾nates a proton to some other substance. According to the Lewis definition, an electron-pair acceptor. Acid anhydride (Sections 2.3 and 20.1): Compound of the type Both R groups are usually the same, although they need not always be. Acid dissociation constant Ka (Section 4.6): Equilibrium con￾stant for dissociation of an acid: Ka [H][A] [HA] RCOCR O X O X CH3CSCoA O X CH3CCH2COCH2CH3 O X O X RCR 2ROH H2O O X RCR W W OR OR H Activating substituent (Sections 12.10 and 12.12): A group that when present in place of a hydrogen causes a particular reaction to occur faster. Term is most often applied to substituents that increase the rate of electrophilic aromatic substitution. Active site (Section 27.20): The region of an enzyme at which the substrate is bound. Acylation (Section 12.7 and Chapter 20): Reaction in which an acyl group becomes attached to some structural unit in a molecule. Examples include the Friedel—Crafts acylation and the conversion of amines to amides. Acyl chloride (Sections 2.3 and 20.1): Compound of the type R may be alkyl or aryl. Acyl group (Sections 12.7 and 20.1): The group R may be alkyl or aryl. Acylium ion (Section 12.7): The cation . Acyl transfer (Section 20.3): A nucleophilic acyl substitution. A reaction in which one type of carboxylic acid derivative is converted to another. Addition (Section 6.1): Reaction in which a reagent X±Y adds to a multiple bond so that X becomes attached to one of the carbons of the multiple bond and Y to the other. 1,2 Addition (Section 10.10): Addition of reagents of the type X±Y to conjugated dienes in which X and Y add to adja￾cent doubly bonded carbons: 1,4 Addition (Section 10.10): Addition of reagents of the type X±Y to conjugated dienes in which X and Y add to the ter￾mini of the diene system: Addition—elimination mechanism (Section 23.6): Two-stage mechanism for nucleophilic aromatic substitution. In the R2CœCH±CHœCR2 R2C±CHœCH±CR2 W X W Y X±Y R2CœCH±CHœCR2 R2C±CH±CHœCR2 W X W Y X±Y R±CPO RC± O X RCCl O X

GLOSSARY tage, the nucleophile adds to the carbon that bears Alkaloid(Section 22.5): Amine that occurs naturally in plants. ing group. In the elimination stage, the leaving The name derives from the fact that such compound weak bases Alkane(Section 2. 1 ): Hydrocarbon in which all the bonds are single bonds. Alkanes have the general formula CnH2n+? (Section 2.1): Hydrocarbon that contains a carbon-ea bon double bond (C=C); also known by the older name Alkoxide ion (Section 5.14): Conjugate base of an alcohol; a Alcohol (Section 4.2): Compound of the type roh Alcohol dehydrogenase(Section 15. 11): Enzyme in the liver Alkylamine(Section 22. 1 ) Amine in which the organic groups that catalyzes the oxidation of alcohols to aldehydes and ke- ttached to nitrogen are alkyl groups Alkylation(Section 9.6): Reaction in which an alkyl group is Aldaric acid (Section 25. 19): Carbohydrate in which car- attached to some structural unit in a molecule boxylic acid functions are present at both ends of the chain Alkyl group (Section 2.10): Structural unit related to an alkane Aldaric acids are typically prepared by oxidation of aldoses by replacing one of the hydrogens by a potential point of at- tachment to some other atom or group. The general symbol Aldehyde( Sections 2.3 and 17. 1): Compound of the type for an alkyl group is r Alkyl halide (Section 4. 1): Compound of the type RX, in which is a halogen substituent(f, Cl Br. D). RCH Alkyloxonium ion (Section 4.6): Positive ion of the type Alditol (Section 25. 18): The polyol obtained on reduction of Alkyne (Section 2. 1 ): Hydrocarbon that contains a carbon-ear the carbonyl group of a carbohydrate. bon triple bond Aldol addition(Section 18.9): Nucleophilic addition of an Allene(Section 10.5): The compound CH2=C=CH dehyde or ketone enolate to the carbonyl group of an Allyl cation(Section 10.2): The carbocation aldehyde or a ketone. The most typical case involves two molecules of an aldehyde, and is usually catalyzed by CH=CHCH The carbocation is stabilized by delocalization of the T ctrons of the double bond. and th shared by the two CH, groups. Substituted analogs of allyl 2RCHCH RCH,CHCHR cation are calle Aldol condensation (Sections 18.9-+8.10): When an aldol ad- dition is carried out so that the B-hydroxy aldehyde or ke- Allylic rearrangement(Section 10.2): Functional group trans formation in which double-bond migration has converted product is described as arising by an aldol condensation one allylic structural unit to another, as in: R,C=CHCH,X-R,CCH=CH 2RCHCH RCH,CH=CR +H,O CH=o Aldonic acid (Section 25. 19): Carboxylic acid obtained by oxi- Amide (Sections 2.3 and 20. 1): Compound of the type RCNR2 ation of the aldehyde function of an aldose. Amine( Chapter 22): Molecule in which a nitrogen-containing Aldose (Section 25. 1): Carbohydrate that contains an aldehyde group of the type -NH2, -NHR, or-NR, is attached to carbonyl group in its open-chain form. an alkyl or aryl group Alicyclic (Section 2.12): Term describing an aliphatic cycl a-Amino acid (Section 27. 1 ): A carboxylic acid that contains tructural unit an amino group at the a-carbon atom a-Amino acids are Aliphatic (Section 2.1): Term applied to compounds that do not the building blocks of peptides and proteins. An a-amino contain benzene or benzene-like rings as structural units mally exists (Historically, aliphatic was used to describe compounds de- rived from fats and oils. RCHCO, Alkadiene (Section 10.5): Hydrocarbon that contains two arbon-earbon double bonds; commonly referred to as Forward Main Menu TOC Study Guide Toc Student OLCMHHE Website

GLOSSARY G-2 Alkaloid (Section 22.5): Amine that occurs naturally in plants. The name derives from the fact that such compounds are weak bases. Alkane (Section 2.1): Hydrocarbon in which all the bonds are single bonds. Alkanes have the general formula CnH2n2. Alkene (Section 2.1): Hydrocarbon that contains a carbon—car￾bon double bond (CœC); also known by the older name olefin. Alkoxide ion (Section 5.14): Conjugate base of an alcohol; a species of the type . Alkylamine (Section 22.1): Amine in which the organic groups attached to nitrogen are alkyl groups. Alkylation (Section 9.6): Reaction in which an alkyl group is attached to some structural unit in a molecule. Alkyl group (Section 2.10): Structural unit related to an alkane by replacing one of the hydrogens by a potential point of at￾tachment to some other atom or group. The general symbol for an alkyl group is R±. Alkyl halide (Section 4.1): Compound of the type RX, in which X is a halogen substituent (F, Cl, Br, I). Alkyloxonium ion (Section 4.6): Positive ion of the type ROH2 . Alkyne (Section 2.1): Hydrocarbon that contains a carbon—car￾bon triple bond. Allene (Section 10.5): The compound CH2œCœCH2. Allyl cation (Section 10.2): The carbocation CH2œCHCH2 The carbocation is stabilized by delocalization of the electrons of the double bond, and the positive charge is shared by the two CH2 groups. Substituted analogs of allyl cation are called allylic carbocations. Allyl group (Sections 5.1, 10.1): The group CH2œCHCH2± Allylic rearrangement (Section 10.2): Functional group trans￾formation in which double-bond migration has converted one allylic structural unit to another, as in: Amide (Sections 2.3 and 20.1): Compound of the type Amine (Chapter 22): Molecule in which a nitrogen-containing group of the type ±NH2, ±NHR, or ±NR2 is attached to an alkyl or aryl group. -Amino acid (Section 27.1): A carboxylic acid that contains an amino group at the -carbon atom. -Amino acids are the building blocks of peptides and proteins. An -amino acid normally exists as a zwitterion. RCHCO2  W NH3 RCNR 2 O X R2CœCHCH2X R2CCHœCH2 W Y R±O  addition stage, the nucleophile adds to the carbon that bears the leaving group. In the elimination stage, the leaving group is expelled. Alcohol (Section 4.2): Compound of the type ROH. Alcohol dehydrogenase (Section 15.11): Enzyme in the liver that catalyzes the oxidation of alcohols to aldehydes and ke￾tones. Aldaric acid (Section 25.19): Carbohydrate in which car￾boxylic acid functions are present at both ends of the chain. Aldaric acids are typically prepared by oxidation of aldoses with nitric acid. Aldehyde (Sections 2.3 and 17.1): Compound of the type Alditol (Section 25.18): The polyol obtained on reduction of the carbonyl group of a carbohydrate. Aldol addition (Section 18.9): Nucleophilic addition of an aldehyde or ketone enolate to the carbonyl group of an aldehyde or a ketone. The most typical case involves two molecules of an aldehyde, and is usually catalyzed by bases. Aldol condensation (Sections 18.9—18.10): When an aldol ad￾dition is carried out so that the -hydroxy aldehyde or ke￾tone dehydrates under the conditions of its formation, the product is described as arising by an aldol condensation. Aldonic acid (Section 25.19): Carboxylic acid obtained by oxi￾dation of the aldehyde function of an aldose. Aldose (Section 25.1): Carbohydrate that contains an aldehyde carbonyl group in its open-chain form. Alicyclic (Section 2.12): Term describing an aliphatic cyclic structural unit. Aliphatic (Section 2.1): Term applied to compounds that do not contain benzene or benzene-like rings as structural units. (Historically, aliphatic was used to describe compounds de￾rived from fats and oils.) Alkadiene (Section 10.5): Hydrocarbon that contains two carbon—carbon double bonds; commonly referred to as a diene. 2RCH2CH O X RCH2CHœCR W CHœO H2O HO heat 2RCH2CH O X RCH2CHCHR W OH W CHœO HO RCH O X ArCH O X or X Y addition X elimination Y X  Y

GLOSSARY L-Amino acid (Section 27. 2): a description of the stereochem Antibonding orbital(Section 1. 14): An orbital in a molecule in istry at the a-carbon atom of a chiral amino acid. The which an electron is less stable than when localized on ar Fischer projection of an a-amino acid has the amino group isolated atom on the left when the carbon chain is vertical with the car Anticodon (Section 27 28): Sequence of three bases in a mole boxyl group at the top cule of tRNa that is complementary to the codon of mRNA for a particular amino acid Anti-Markovnikov addition (Sections 6.8, 6.11): Addition re- H3N action for which the regioselectivity is opposite to that pre dicted on the basis of markovnikov's rul protic solvent(Section 8.12): A solvent that does not have Amino acid racemization (Section 27. 2)a method fc easily exchangeable protons such as those bonded to oxy- archeological samples based on the rate at which gen of hydroxyl groups geochemistry at the a carbon of amino acid compon Ar-(Section 2.2): Symbol for an aryl group randomized. It is useful for samples too old to be Arene(Section 2. 1 ) Aromatic hydrocarbon. Often abbreviated dated byC decay ArH Amino acid residues (Section 27.7): Individual amino acid Arenium ion( Section 12.2): The carbocation intermediate components of a peptide or protein formed by attack of an electrophile on an aromatic substrate Amino sugar (Section 25. 11): Carbohydrate in which one of in electrophilic aromatic substitution. See cyclohexadienyl the hydroxyl groups has been replaced by an amino group cation Amylopectin (Section 25. 15): A polysaccharide present in Aromatic compound (Section 11.3): An electron-delocalized starch. Amylopectin is a polymer of a(1, 4)-linked glucose species that is much more stable than any structure written units, as is amylose(see amylose). Unlike amylose, amy for it in which all the electrons are localized either in co lopectin contains branches of 24-30 glucose units con- lent bonds or as unshared electron pairs nected to the main chain by an a(1, 6) linkage. Aromaticity (Section 11.4): Special stability associated with Amylose (Section 25. 15): The water-dispersible component of aromatic compounds starch. It is a polymer of o(1, 4)-linked glucose Arylamine(Section 22.1): An amine that has an aryl group at- Anabolic steroid (Section 26. 15): A steroid that promotes mus ached to the amin Aryne (Section 23.8): A species that contains a triple bond Androgen (Section 26.15): A male sex hormone within an aromatic ring Angle strain (Section 3. 4): The strain a molecule possesses be- Asymmetric(Section 7.1): Lacking all significant symmetry cause its bond angles are distorted from their normal values elements; an asymmetric object does not have a plane, axis, Anion (Section 1. 2): Negatively charged ion. center of symmetry. Annulene (Section 11. 19): Monocyclic hydrocarbon character- Asymmetric center (Section 7. 2): Obsolete name for a ste ed by a completely conjugated system of double bonds neogenic center Annulenes may or may not be aromatic. Atactic polymer(Section 7. 15): Polymer characterized by ran- Anomeric carbon (Section 25.6): The carbon atom in a fura- dom stereochemistry at its stereogenic centers. An atactic nose or pyranose form that is derived from the carbonyl car- polymer, unlike an isotactic or a syndiotactic polymer, is bon of the open-chain form. It is the ring carbon that is not a stereoregular bonded to two oxygens. Atomic number(Section 1. 1): The number of protons in the Anomeric effect(Section 25.8): The preference for an elec nucleus of a particular atom. The symbol for atomic number tronegative substituent, especially a hydroxyl group, to oc- is Z, and each element has a unique atomic number. cupy an axial orientation when bonded to the anomeric car Axial bond (Section 3.6): a bond to a carbon in the chair con- bon in the pyranose form of a carbohydrate formation of cyclohexane oriented like the six "up-and Anti (Section 3. 1): Term describing relative position of two down"bonds in the following: substituents on adjacent atoms when the angle between their bonds is on the order of 180. Atoms X and y in the structure shown are anti to each other (Section 22 19): Formation of a compound of the =NAr by reaction of an aryl diazonium salt with The arene must be strongly activated toward elec- aromatic substitution; that is, it must bear a power ful electron-releasing substituent such as-OH or-NR, Anti addition ( Section 6.3): Addition reaction in which the tw portions of the attacking reagent X-Y add to opposite faces of the double bond Forward Main Menu TOC Study Guide Toc Student OLCMHHE Website

G-3 GLOSSARY L-Amino acid (Section 27.2): A description of the stereochem￾istry at the -carbon atom of a chiral amino acid. The Fischer projection of an -amino acid has the amino group on the left when the carbon chain is vertical with the car￾boxyl group at the top. Amino acid racemization (Section 27.2) A method for dating archeological samples based on the rate at which the ste￾reochemistry at the carbon of amino acid components is randomized. It is useful for samples too old to be reliably dated by 14C decay. Amino acid residues (Section 27.7): Individual amino acid components of a peptide or protein. Amino sugar (Section 25.11): Carbohydrate in which one of the hydroxyl groups has been replaced by an amino group. Amylopectin (Section 25.15): A polysaccharide present in starch. Amylopectin is a polymer of (1,4)-linked glucose units, as is amylose (see amylose). Unlike amylose, amy￾lopectin contains branches of 24—30 glucose units con￾nected to the main chain by an (1,6) linkage. Amylose (Section 25.15): The water-dispersible component of starch. It is a polymer of (1,4)-linked glucose units. Anabolic steroid (Section 26.15): A steroid that promotes mus￾cle growth. Androgen (Section 26.15): A male sex hormone. Angle strain (Section 3.4): The strain a molecule possesses be￾cause its bond angles are distorted from their normal values. Anion (Section 1.2): Negatively charged ion. Annulene (Section 11.19): Monocyclic hydrocarbon character￾ized by a completely conjugated system of double bonds. Annulenes may or may not be aromatic. Anomeric carbon (Section 25.6): The carbon atom in a fura￾nose or pyranose form that is derived from the carbonyl car￾bon of the open-chain form. It is the ring carbon that is bonded to two oxygens. Anomeric effect (Section 25.8): The preference for an elec￾tronegative substituent, especially a hydroxyl group, to oc￾cupy an axial orientation when bonded to the anomeric car￾bon in the pyranose form of a carbohydrate. Anti (Section 3.1): Term describing relative position of two substituents on adjacent atoms when the angle between their bonds is on the order of 180°. Atoms X and Y in the structure shown are anti to each other. Anti addition (Section 6.3): Addition reaction in which the two portions of the attacking reagent X±Y add to opposite faces of the double bond. X Y CO2  H3N H R Antibonding orbital (Section 1.14): An orbital in a molecule in which an electron is less stable than when localized on an isolated atom. Anticodon (Section 27.28): Sequence of three bases in a mole￾cule of tRNA that is complementary to the codon of mRNA for a particular amino acid. Anti-Markovnikov addition (Sections 6.8, 6.11): Addition re￾action for which the regioselectivity is opposite to that pre￾dicted on the basis of Markovnikov’s rule. Aprotic solvent (Section 8.12): A solvent that does not have easily exchangeable protons such as those bonded to oxy￾gen of hydroxyl groups. Ar± (Section 2.2): Symbol for an aryl group. Arene (Section 2.1): Aromatic hydrocarbon. Often abbreviated ArH. Arenium ion (Section 12.2): The carbocation intermediate formed by attack of an electrophile on an aromatic substrate in electrophilic aromatic substitution. See cyclohexadienyl cation. Aromatic compound (Section 11.3): An electron-delocalized species that is much more stable than any structure written for it in which all the electrons are localized either in cova￾lent bonds or as unshared electron pairs. Aromaticity (Section 11.4): Special stability associated with aromatic compounds. Arylamine (Section 22.1): An amine that has an aryl group at￾tached to the amine nitrogen. Aryne (Section 23.8): A species that contains a triple bond within an aromatic ring (see benzyne). Asymmetric (Section 7.1): Lacking all significant symmetry elements; an asymmetric object does not have a plane, axis, or center of symmetry. Asymmetric center (Section 7.2): Obsolete name for a ste￾reogenic center. Atactic polymer (Section 7.15): Polymer characterized by ran￾dom stereochemistry at its stereogenic centers. An atactic polymer, unlike an isotactic or a syndiotactic polymer, is not a stereoregular polymer. Atomic number (Section 1.1): The number of protons in the nucleus of a particular atom. The symbol for atomic number is Z, and each element has a unique atomic number. Axial bond (Section 3.6): A bond to a carbon in the chair con￾formation of cyclohexane oriented like the six “up-and￾down” bonds in the following: Azo coupling (Section 22.19): Formation of a compound of the type ArNœNAr by reaction of an aryl diazonium salt with an arene. The arene must be strongly activated toward elec￾trophilic aromatic substitution; that is, it must bear a power￾ful electron-releasing substituent such as ±OH or ±NR2.

GLOSSARY Benzylic carbon (Section 11.10): A carbon directly attached to Baeyer strain theory (Section 3.4): Incorrect nineteenth-cen a benzene ring. a hydrogen attached to a benzylic carbon is tury theory that considered the rings of cycloalkanes to be a benzylic hydrogen. A carbocation in which the benzylic planar and assessed their stabilities according to how much carbon is positively charged is a benzylic carbocation. A the angles of a corresponding regular polygon deviated free radical in which the benzy lic carbon bears the unpaired from the tetrahedral value of 109,5o lectron is a benzylic radical. aeyer-illiger oxidation( Section 17.16): Oxidation of an Benzyne(Section 23.8): The compound hyde or, more commonly, a ketone with a peroxy acid The product of Baeyer-Villiger oxidation of a ketone is an ester RCR Ball-and-stick model(Section 1.10): Type of molecular model n which balls representing atoms are connected by sticks Benzyne is formed as a reactive representing bonds. Similar to ball-and-spoke models of of aryl halides with very stror Learning By Modeling Base(Section 4.6): According to the Arrhenius definition, Bile acids (Section 26.13): Steroid derivatives biosynthesized ubstance that ionizes in water to produce hydroxide ions the liver that aid digestion by emulsifying fats. According to the Bronsted-towry definition, a substance Bimolecular (Section 4.7): A process in which two particles re- that accepts a proton from some suitable donor. According act in the same elementary ster to the Lewis definition, an electron-pair donor. Biological isoprene unit (Section 26.8): Isopentenyl pyrophos- Base pair(Section 27. 27): Term given to the purine of a nu phate, the biological precursor to terpenes and steroids: cleotide and its complementary pyrimidine Adenine(A)is omplementary to thymine(T), and guanine(G)is comple entary to cytosine( C). Base peak (Section 13.21): The most intense peak in a mass spectrum. The base peak is assigned a relative intensity of Birch reduction(Section 11.11): Reduction of an aromatic ring 100, and the intensities of all other peaks are cited as a per- to a 1, 4-cyclohexadiene on treatment with a group I metal entage of the base (i, Na, K)and an alcohol in liquid ammonia. Basicity constant Kb(Section 22. 4):A measure of bas Boat conformation (Section 3.5): An unstable conform cyclohexane, depicted a Kb=IRyNH*HO-I IRa Bending vibration(Section 13. 19): The regular, repetitive mo- tion of an atom or a group along an arc the radius of whic is the bond connecting the atom or group to the rest of the T bond ( Section 1. 17): In alkenes, a bond formed by overlap of type of molecular orbitals in a side-by-side manner. A T bond is weaker than motion that gives rise to a peak in the infrared spectrum. a o bond. The carbon -earbon double bond in alkenes con- Benedict's reagent (Section 25. 19): A solution containing the ists of two sp-hybridized carbons joined by a g bond and citrate complex of CuSO4. It is used to test for the presence of reducing sugars o bond (Section 1.14): A connection between two atoms in Benzene(Section 11. 1): The most typical aromatic hydrocar hich the electron probability distribution has rotational symmetry along the internuclear axis. A cross section per- pendicular to the internuclear axis is a circle Bond dissociation energy (Section 1.3): For a substance A: B, the energy required to break the bond between A and b so that each retains one of the electrons in the bond table 4.3 (Section 4.17)gives bond dissociation energies for some representative compounds Bonding orbital(Section 1. 14): An orbital in a molecule in which an electron is more stable than when localized on an Benzyl group (Section 11.7): The group C6HSCH isolated atom. All the bonding orbitals are normally doubl occupied in stable neutral molecules Forward Main Menu TOC Study Guide Toc Student OLCMHHE Website

GLOSSARY G-4 Baeyer strain theory (Section 3.4): Incorrect nineteenth-cen￾tury theory that considered the rings of cycloalkanes to be planar and assessed their stabilities according to how much the angles of a corresponding regular polygon deviated from the tetrahedral value of 109.5°. Baeyer—Villiger oxidation (Section 17.16): Oxidation of an aldehyde or, more commonly, a ketone with a peroxy acid. The product of Baeyer—Villiger oxidation of a ketone is an ester. Ball-and-stick model (Section 1.10): Type of molecular model in which balls representing atoms are connected by sticks representing bonds. Similar to ball-and-spoke models of Learning By Modeling. Base (Section 4.6): According to the Arrhenius definition, a substance that ionizes in water to produce hydroxide ions. According to the Brønsted—Lowry definition, a substance that accepts a proton from some suitable donor. According to the Lewis definition, an electron-pair donor. Base pair (Section 27.27): Term given to the purine of a nu￾cleotide and its complementary pyrimidine. Adenine (A) is complementary to thymine (T), and guanine (G) is comple￾mentary to cytosine (C). Base peak (Section 13.21): The most intense peak in a mass spectrum. The base peak is assigned a relative intensity of 100, and the intensities of all other peaks are cited as a per￾centage of the base peak. Basicity constant Kb (Section 22.4): A measure of base strength, especially of amines. Kb Bending vibration (Section 13.19): The regular, repetitive mo￾tion of an atom or a group along an arc the radius of which is the bond connecting the atom or group to the rest of the molecule. Bending vibrations are one type of molecular motion that gives rise to a peak in the infrared spectrum. Benedict’s reagent (Section 25.19): A solution containing the citrate complex of CuSO4. It is used to test for the presence of reducing sugars. Benzene (Section 11.1): The most typical aromatic hydrocar￾bon: Benzyl group (Section 11.7): The group C6H5CH2±. H H H H H H [R3NH][HO] [R3N] RCR O X RCOR O X RCOOH O X Benzylic carbon (Section 11.10): A carbon directly attached to a benzene ring. A hydrogen attached to a benzylic carbon is a benzylic hydrogen. A carbocation in which the benzylic carbon is positively charged is a benzylic carbocation. A free radical in which the benzylic carbon bears the unpaired electron is a benzylic radical. Benzyne (Section 23.8): The compound Benzyne is formed as a reactive intermediate in the reaction of aryl halides with very strong bases such as potassium amide. Bile acids (Section 26.13): Steroid derivatives biosynthesized in the liver that aid digestion by emulsifying fats. Bimolecular (Section 4.7): A process in which two particles re￾act in the same elementary step. Biological isoprene unit (Section 26.8): Isopentenyl pyrophos￾phate, the biological precursor to terpenes and steroids: Birch reduction (Section 11.11): Reduction of an aromatic ring to a 1,4-cyclohexadiene on treatment with a group I metal (Li, Na, K) and an alcohol in liquid ammonia. Boat conformation (Section 3.5): An unstable conformation of cyclohexane, depicted as bond (Section 1.17): In alkenes, a bond formed by overlap of p orbitals in a side-by-side manner. A bond is weaker than a  bond. The carbon—carbon double bond in alkenes con￾sists of two sp2 -hybridized carbons joined by a  bond and a bond.  bond (Section 1.14): A connection between two atoms in which the electron probability distribution has rotational symmetry along the internuclear axis. A cross section per￾pendicular to the internuclear axis is a circle. Bond dissociation energy (Section 1.3): For a substance A:B, the energy required to break the bond between A and B so that each retains one of the electrons in the bond. Table 4.3 (Section 4.17) gives bond dissociation energies for some representative compounds. Bonding orbital (Section 1.14): An orbital in a molecule in which an electron is more stable than when localized on an isolated atom. All the bonding orbitals are normally doubly occupied in stable neutral molecules. OPP H H H H

G-5 GLOSSARY ond-line formula (Section 1.7): Formula in which connec- Carboxylate ion( Section 19.5): The conjugate base of a car tions between carbons are shown but individual carbons boxylic acid, an ion of the type RCO2 and hydrogens are not The bond-line formula Carboxylation (Section 19. 11): In the preparation of a car- boxylic acid, the reaction of a carbanion with carbon diox ide. Typically, the carb RMgX RCOH presents the compound (CH3)2 CHCH,CH3 undary surface(Section 1. 1 ) The surface that encloses the Carboxylic acid(Sections 2.3 and 19.1): Compound of the typ region where the probability of finding an electron is high (90-95%) Branched-chain carbohydrate (Section 25.12): Carbohydrate RCOH. also written as RCO, H. which the main carbon chain bears a carbon su Carboxylic acid derivative (Section 20. 1): Compound that in place of a hydrogen or hydroxyl gre yields a carboxylic acid on hydrolysis. Carboxylic acid de- romohydrin( Section 6.17): A halohydrin in which the halo- rivatives include acyl chlorides, anhydrides, esters, and gen is bromine(see halohydrin) amides Bromonium ion(Section 6.16): A halonium ion in which the Carotenoids (Section 26. 16): Naturally occurring tetrater halogen is bromine(see halonium ion). peroid plant pigments Bronsted acid See acid Cation (Section 1.2): Positively charged ion. Bronsted base see base Cellobiose (Section 25. 14): A disaccharide in which two glu Buckminsterfullerene(Chapter 11, box, "Carbon Clusters cose units are joined by a B(1, 4)linkage Cellobiose is ob Fullerenes, and Nanotubes"): Name given to the Cso cluster tained by the hydrolysis of cellulose. with structure resembling the geodesic domes of R. Buck- Cellulose(Section 25. 15): A polysaccharide in which thou- Ister Fuller. see front cover sands of glucose units are joined by B(1, 4) linkages. n-Butan (Section 2.5): Common name for butane Center of symmetry(Section 7.3): A point in the center of a CHaCHCh,cH structure located so that a line drawn from it to any element n-Butyl group(Section 2.10): The group CHa CH, CH, CH2-. of the structure, when extended an equal distance in the op sec-Butyl group (Section 2.10): The group posite direction, encounters an identical element. Benzene, for example, has a center of symmetry CH3CH_CHCH3 Chain reaction(Section 4. 18): Reaction mechanism in which a sequence of individual steps repeats itself many times, usu- tert-Butyl group(Section 2.10): The group(CH3)3C- ally because a reactive intermediate consumed in one step regenerated in a subsequent step. The halogenation of alkanes is a chain reaction proceeding via free-radical Cahn-ngold-Prelog notation(Section 7.6): System for spec- intermediates ifying absolute configuration as R or S on the basis of the Chair conformation (Section 3.5 ): The most stable conforma- order in which atoms or groups are attached to a stereogenic center. Groups are ranked in order of precedence according to rules based on atomic number Carbamate(Section 20. 17): An ester of carbamic acid Carbanion(Section 9.5): Anion in which the negative charge is Chemical shift (Section 13.4): A measure of how shielded the borne by carbon. An example is acetylide ion. Carbene(Section 14. 13): A neutral species in which one of the have different chemical shifts. and nuclei of the same atom carbon atoms is associated with six valence electrons have chemical shifts that are sensitive to their molecular Carbinolamine (Section 17.10): Compound of the type environment. In proton and carbon-13 NMR, chemica shifts are cited as 8, or parts per million(ppm), from the hy drogens or carbons, respectively, of tetramethylsilane HO-C-NR, Chiral(Section 7. 1): Term describing an object that is not su- perposable on its mirror image. Carbinolamines are formed by nucleophilic addition of an Chiral carbon atom ( Section 7. 2): a carbon that is bonded to amine to a carbonyl group and are intermediates in the for- four groups, all of which are different from one another. mation of imines and enamines Also called an asymmetric carbon atom. A more modern term Is stereogenIc center Carbocation (Section 4.9): Positive ion in which the charge re- Chiral center(Section 7.2): See stereogenic center sides on carbon. An example is tert-butyl cation, (CH3)C Carbocations are unstable species that, though they cannot Chlorohydrin(Section 6.17): A halohydrin in which the halo- normally be isolated, are believed to be intermediates in gen is chlorine(see halohydrin certain reactions Forward Main Menu TOC Study Guide Toc Student OLCMHHE Website

G-5 GLOSSARY Bond-line formula (Section 1.7): Formula in which connec￾tions between carbons are shown but individual carbons and hydrogens are not. The bond-line formula represents the compound (CH3)2CHCH2CH3. Boundary surface (Section 1.1): The surface that encloses the region where the probability of finding an electron is high (90—95%). Branched-chain carbohydrate (Section 25.12): Carbohydrate in which the main carbon chain bears a carbon substituent in place of a hydrogen or hydroxyl group. Bromohydrin (Section 6.17): A halohydrin in which the halo￾gen is bromine (see halohydrin). Bromonium ion (Section 6.16): A halonium ion in which the halogen is bromine (see halonium ion). Brønsted acid See acid. Brønsted base See base. Buckminsterfullerene (Chapter 11, box, “Carbon Clusters, Fullerenes, and Nanotubes”): Name given to the C60 cluster with structure resembling the geodesic domes of R. Buck￾minster Fuller; see front cover. n-Butane (Section 2.5): Common name for butane CH3CH2CH2CH3. n-Butyl group (Section 2.10): The group CH3CH2CH2CH2±. sec-Butyl group (Section 2.10): The group tert-Butyl group (Section 2.10): The group (CH3)3C±. Cahn—Ingold—Prelog notation (Section 7.6): System for spec￾ifying absolute configuration as R or S on the basis of the order in which atoms or groups are attached to a stereogenic center. Groups are ranked in order of precedence according to rules based on atomic number. Carbamate (Section 20.17): An ester of carbamic acid (H2NCO2H); a compound of the type H2NCO2R. Carbanion (Section 9.5): Anion in which the negative charge is borne by carbon. An example is acetylide ion. Carbene (Section 14.13): A neutral species in which one of the carbon atoms is associated with six valence electrons. Carbinolamine (Section 17.10): Compound of the type Carbinolamines are formed by nucleophilic addition of an amine to a carbonyl group and are intermediates in the for￾mation of imines and enamines. Carbocation (Section 4.9): Positive ion in which the charge re￾sides on carbon. An example is tert-butyl cation, (CH3)3C. Carbocations are unstable species that, though they cannot normally be isolated, are believed to be intermediates in certain reactions. W W HO±C±NR2 CH3CH2CHCH3 W Carboxylate ion (Section 19.5): The conjugate base of a car￾boxylic acid, an ion of the type RCO2 . Carboxylation (Section 19.11): In the preparation of a car￾boxylic acid, the reaction of a carbanion with carbon diox￾ide. Typically, the carbanion source is a Grignard reagent. Carboxylic acid (Sections 2.3 and 19.1): Compound of the type , also written as RCO2H. Carboxylic acid derivative (Section 20.1): Compound that yields a carboxylic acid on hydrolysis. Carboxylic acid de￾rivatives include acyl chlorides, anhydrides, esters, and amides. Carotenoids (Section 26.16): Naturally occurring tetrater￾penoid plant pigments. Cation (Section 1.2): Positively charged ion. Cellobiose (Section 25.14): A disaccharide in which two glu￾cose units are joined by a (1,4) linkage. Cellobiose is ob￾tained by the hydrolysis of cellulose. Cellulose (Section 25.15): A polysaccharide in which thou￾sands of glucose units are joined by (1,4) linkages. Center of symmetry (Section 7.3): A point in the center of a structure located so that a line drawn from it to any element of the structure, when extended an equal distance in the op￾posite direction, encounters an identical element. Benzene, for example, has a center of symmetry. Chain reaction (Section 4.18): Reaction mechanism in which a sequence of individual steps repeats itself many times, usu￾ally because a reactive intermediate consumed in one step is regenerated in a subsequent step. The halogenation of alkanes is a chain reaction proceeding via free-radical intermediates. Chair conformation (Section 3.5): The most stable conforma￾tion of cyclohexane: Chemical shift (Section 13.4): A measure of how shielded the nucleus of a particular atom is. Nuclei of different atoms have different chemical shifts, and nuclei of the same atom have chemical shifts that are sensitive to their molecular environment. In proton and carbon-13 NMR, chemical shifts are cited as , or parts per million (ppm), from the hy￾drogens or carbons, respectively, of tetramethylsilane. Chiral (Section 7.1): Term describing an object that is not su￾perposable on its mirror image. Chiral carbon atom (Section 7.2): A carbon that is bonded to four groups, all of which are different from one another. Also called an asymmetric carbon atom. A more modern term is stereogenic center. Chiral center (Section 7.2): See stereogenic center. Chlorohydrin (Section 6.17): A halohydrin in which the halo￾gen is chlorine (see halohydrin). RCOH O X RMgX RCO2H 1. CO2 2. H3O

GLOSSARY Chloronium ion (Section 6.16): A halonium ion in which th Codon (Section 27 28): Set of three successive nucleotides halogen is chlorine(see halonium ion). mRNA that is unique for a particular amino acid. The 64 Cholesterol (Section 26. 11): The most abundant steroid in codons possible from combinations of A, T, G, and C code mals and the biological precursor to other naturally occur for the 20 amino acids from which proteins are constr ring steroids. including the bile acids. sex hormones and Coenzyme (Section 27. 21): Molecule that acts in combi with an enzyme to bring about a reaction. Chromatography(Section 13. 21): A method for separation and CoenzymeQ (Section 24 14): Naturally occurring group of re- analysis of mixtures based on the different rates at which lated quinones involved in the chemistry of cellular respira- different compounds are removed from a stationary phas tion. also known as ubiquinone Combinatorial chemistry (Section 27.18): A method for carry Chromophore (Section 13.20): The structural unit of a mole ing out a large number of reactions on a small scale in the cule principally responsible for absorption of radiation of a solid phase so as to generate a"library"of related com- particular frequency; a term usually applied to ultraviolet- pounds for further study, such as biological testing. visible spectroscopy. Combustion(Section 2.15): Burning of a substance in the pres- Chymotrypsin(Section 27. 10): A digestive enzyme that cat- ence of oxygen. All hydrocarbons yield carbon dioxide and alyzes the hydrolysis of proteins. Chymotrypsin selectively when they undergo combustion. catalyzes the cleavage of the peptide bond between the car ommon nomenclature (Section 2. 8): Names given to com- pounds on some basis other than a comprehensive system- tic set of rules cis-(Section 3.12): Stereochemical prefix indicating that two Concerted reaction (Section 4.7): Reaction that occurs in a sin- substituents are on the same side of a ring or double bond gle elementary step (Contrast with the prefix trans-) Condensation polymer(Section 20.16): Polymer in which the Claisen condensation (Section 21.1): Reaction in which a bonds that connect the monomers are formed by condensa- B-keto ester is formed by condensation of two moles of tion reactions. Typical condensation polymers include poly ester in base esters and polyamides. Condensation reaction (Section 15.7): Reaction in which twe molecules combine to give a product accompanied by the RCH, COR RCH-CCHCOR′+R'OH expulsion of some small stable molecule(such as water). An example is acid-catalyzed ether formation Claisen rearrangement (Section 24. 13): Thermal conversion ROR + H20 of an allyl phenyl ether to an o-allyl phenol. The rearrange Condensed structural formula (Section 1.7): A standard way ment proceeds via a cyclohexadienone intermediate of representing structural formulas in which subscripts are used to indicate replicated atoms or groups, as in H2- (CH3)2CHCH2CH Conformational analysis(Section 3. 1 ): Study of the conforma CH CH,CH=CH tions available to a molecule. their relative stabi role they play in defining the properties of the molecule. Claisen-Schmidt condensation (Section 18.10): A mixed al- molecule generated by rotation about single bond ons of Conformations (Section 3. 1): Nonidentical representa dol condensation involving a ketone enolate and an aro- matic aldehyde or ketone. Conformers (Section 3. 1 ): Different conformations of a single Clathrate(Section 2.4): A mixture of two substances in which molecule molecules of the minor component are held by van der onjugate acid(Section 4.6): The species formed from a Bron- Waals forces within a framework of molecules of the major Conjugate addition(Sections 10.10 and 18.12 Addition read oinonen tion in which the reagent adds to the termini of the conju- Clemmensen reduction (Section 12.8): Method for reducing the carbonyl group of aldehydes and ketones to a methylene gated system with migration of the double bond; synony- roup(C=0- CH,) by treatment with zinc amalgam mous with 1, 4 addition. The most common examples [Zn(Hg)] in concentrated hydrochloric acid include conjugate addition to 1, 3-dienes and to a, B-unsatu- Closed-shell electron configuration (Sections 1.1 and 11 rated carbonyl compounds. Stable electron configuration in which all the lowest onjugate base (Section 4.6): The species formed from a Bronsted acid after it has donated orbitals of an atom (in the case of the noble gases), an ion Conjugated diene(Section 10.5): System of the type C NMR (Section 13.14): Nuclear magnetic resonance spec C=C-C=C, in which two pairs of doubly bonded car troscopy in which the environments of individual carbon bons are joined by a single bond. The T electrons are de- localized over the unit of four consecutive sp-hybridized atoms are examined via their mass 13 isotope. Forward Main Menu TOC Study Guide Toc Student OLCMHHE Website

GLOSSARY G-6 Chloronium ion (Section 6.16): A halonium ion in which the halogen is chlorine (see halonium ion). Cholesterol (Section 26.11): The most abundant steroid in ani￾mals and the biological precursor to other naturally occur￾ring steroids, including the bile acids, sex hormones, and corticosteroids. Chromatography (Section 13.21): A method for separation and analysis of mixtures based on the different rates at which different compounds are removed from a stationary phase by a moving phase. Chromophore (Section 13.20): The structural unit of a mole￾cule principally responsible for absorption of radiation of a particular frequency; a term usually applied to ultraviolet￾visible spectroscopy. Chymotrypsin (Section 27.10): A digestive enzyme that cat￾alyzes the hydrolysis of proteins. Chymotrypsin selectively catalyzes the cleavage of the peptide bond between the car￾boxyl group of phenylalanine, tyrosine, or tryptophan and some other amino acid. cis- (Section 3.12): Stereochemical prefix indicating that two substituents are on the same side of a ring or double bond. (Contrast with the prefix trans-.) Claisen condensation (Section 21.1): Reaction in which a -keto ester is formed by condensation of two moles of an ester in base: Claisen rearrangement (Section 24.13): Thermal conversion of an allyl phenyl ether to an o-allyl phenol. The rearrange￾ment proceeds via a cyclohexadienone intermediate. Claisen—Schmidt condensation (Section 18.10): A mixed al￾dol condensation involving a ketone enolate and an aro￾matic aldehyde or ketone. Clathrate (Section 2.4): A mixture of two substances in which molecules of the minor component are held by van der Waals forces within a framework of molecules of the major component. Clemmensen reduction (Section 12.8): Method for reducing the carbonyl group of aldehydes and ketones to a methylene group (CœO ±£ CH2) by treatment with zinc amalgam [Zn(Hg)] in concentrated hydrochloric acid. Closed-shell electron configuration (Sections 1.1 and 11.6): Stable electron configuration in which all the lowest energy orbitals of an atom (in the case of the noble gases), an ion (e.g., Na), or a molecule (e.g., benzene) are filled. 13C NMR (Section 13.14): Nuclear magnetic resonance spec￾troscopy in which the environments of individual carbon atoms are examined via their mass 13 isotope. heat O CH2 CH CH2 CH2CH OH CH2 RCH2COR O X RCH2CCHCOR O X O X W R ROH 1. NaOR 2. H Codon (Section 27.28): Set of three successive nucleotides in mRNA that is unique for a particular amino acid. The 64 codons possible from combinations of A, T, G, and C code for the 20 amino acids from which proteins are constructed. Coenzyme (Section 27.21): Molecule that acts in combination with an enzyme to bring about a reaction. Coenzyme Q (Section 24.14): Naturally occurring group of re￾lated quinones involved in the chemistry of cellular respira￾tion. Also known as ubiquinone. Combinatorial chemistry (Section 27.18): A method for carry￾ing out a large number of reactions on a small scale in the solid phase so as to generate a “library” of related com￾pounds for further study, such as biological testing. Combustion (Section 2.15): Burning of a substance in the pres￾ence of oxygen. All hydrocarbons yield carbon dioxide and water when they undergo combustion. Common nomenclature (Section 2.8): Names given to com￾pounds on some basis other than a comprehensive, system￾atic set of rules. Concerted reaction (Section 4.7): Reaction that occurs in a sin￾gle elementary step. Condensation polymer (Section 20.16): Polymer in which the bonds that connect the monomers are formed by condensa￾tion reactions. Typical condensation polymers include poly￾esters and polyamides. Condensation reaction (Section 15.7): Reaction in which two molecules combine to give a product accompanied by the expulsion of some small stable molecule (such as water). An example is acid-catalyzed ether formation: Condensed structural formula (Section 1.7): A standard way of representing structural formulas in which subscripts are used to indicate replicated atoms or groups, as in (CH3)2CHCH2CH3. Conformational analysis (Section 3.1): Study of the conforma￾tions available to a molecule, their relative stability, and the role they play in defining the properties of the molecule. Conformations (Section 3.1): Nonidentical representations of a molecule generated by rotation about single bonds. Conformers (Section 3.1): Different conformations of a single molecule. Conjugate acid (Section 4.6): The species formed from a Brøn￾sted base after it has accepted a proton. Conjugate addition (Sections 10.10 and 18.12): Addition reac￾tion in which the reagent adds to the termini of the conju￾gated system with migration of the double bond; synony￾mous with 1,4 addition. The most common examples include conjugate addition to 1,3-dienes and to ,-unsatu￾rated carbonyl compounds. Conjugate base (Section 4.6): The species formed from a Brønsted acid after it has donated a proton. Conjugated diene (Section 10.5): System of the type CœC±CœC, in which two pairs of doubly bonded car￾bons are joined by a single bond. The electrons are de￾localized over the unit of four consecutive sp2 -hybridized carbons. 2ROH ROR H2O H2SO4

G-7 GLOSSARY Connectivity (Section 1.7): Order in which a molecules atoms are connected. Synonymous with constitution Constitution (Section 1.7): Order of atomic connections that defines a molecule Constitutional isomers(Section 1.8): Isomers that differ in re- the n which the atoms are connected Butane (CH3 CH2CH2CH3)and isobutane [(CH3)3CH] are constitu tional isomers Cyclohexadienyl cation ( Section 12. 2): The key intermediate Copolymer (Section 10. 11): Polymer formed from two or more in electrophilic aromatic substitution reactions. It is repr ferent monome sented by the general structure Coupling constant J (Section 13.7) of the extent to hich two nuclear spins are couple simplest cases, it is equal to the distance betweer t peaks in a split NMR signal. Covalent bond (Section 1.3): Chemical bond between tw atoms that results from their sharing of two electrons petroleo m refining in which high-molecular-weight hydrocarbons are converted where e is derived from the electrophile that attacks the to lower molecular-weight ones by thermal or catalytic ca bon-earbon bond cleavage Critical micelle concentration ( Section 19.5): Concentration bove which substances such as salts of fatty acids aggre- Deactivating substituent (Sections 12.11 and 12.13): A gate to form micelles in aqueous solution. that when present in place of a hydrogen substituent Crown ether(Section 16. 4): A cyclic polyether that, via a particular reaction to occur more slowly. The term most ion-dipole attractive forces, forms stable complexes with often applied to the effect of substituents on the rate metal ions. Such complexes, along with their accompany- Debye unit(D)(Section 1.5): Unit customarily used for mea- ing anion, are soluble in nonpolar solvents C terminus (Section 27.7): The amino acid at the end of a pep- suring dipole moments tide or protein chain that has its carboxyl group intact that 1D=1×10-18 esu.cm is, in which the carboxyl group is not part of a peptide bond. Cumulated diene (Section 10.5): Diene of the type C=C=C, carboxylation(Section 19.17): Reaction of the type in which a single carbon atom participates in double bonds RCO,H - RH CO,, in which carbon dioxide is lost two others from a carboxylic acid. Decarboxylation normally occurs yanohydrin (Section 17.7): Compound of the type readily only when the carboxylic acid is a 1, 3-dicarboxylic Decoupling (Section 13. 17): In NMR spectroscopy, any RCR' process that destroys the coupling of nuclear spins between two nuclei. Two types of decoupling are employed inC NMR spectroscopy. Broadband decoupling removes all the Cyanohydrins are formed by nucleophilic addition of HCN H-C couplings; off-resonance decoupling removes all of H-C couplings except those between directly bonded atoms cycloaddition (Section 10. 12): Addition, such as the Dehydration(Section 5.9): Removal of H and OH from adja Diels-Alder reaction, in which a ring is formed ia a cyclic transition state rm is most commonly employed in ycloalkane(Section 2. 12): An alkane in which a ring of car preparation of alkenes by heating alcohols in the presence of an acid catal bon atoms is present. Cycloalkene(Section 5. 1 ) A cyclic hydrocarbon characterized Dehydrogenation(Section 5.1): Removal of the elements of H2 from adjacent atoms. The term is most commonly en by a double bond between two of the ring carbons. Cycloalkyne (Section 9.4): A cyclic hydrocarbon characterized countered in the industrial preparation of ethylene from by a triple bond between two of the ring carbons. ethane, propene from propane, 1, 3-butadiene from butane, and styrene from ethy benzene. Cyclohexadienyl anion(Section 23. 6): The key intermediate in nucleophilic aromatic substitution by the addition-elimina- Dehydrohalogenation(Section 5. 14): Reaction in which an alkyl halide, on being treated with a base such as sodium tion mechanism. It is represented by the general structure shown, where Y is the nucleophile and X is the leaving ethoxide, is converted to an alkene by loss of a proton fro one carbon and the halogen from the adjacent carbon. Delocalization (Section 1.9): Association of an electron with more than one atom. The simplest example is the shared Forward Main Menu TOC Study Guide Toc Student OLCMHHE Website

G-7 GLOSSARY Connectivity (Section 1.7): Order in which a molecule’s atoms are connected. Synonymous with constitution. Constitution (Section 1.7): Order of atomic connections that defines a molecule. Constitutional isomers (Section 1.8): Isomers that differ in re￾spect to the order in which the atoms are connected. Butane (CH3CH2CH2CH3) and isobutane [(CH3)3CH] are constitu￾tional isomers. Copolymer (Section 10.11): Polymer formed from two or more different monomers. Coupling constant J (Section 13.7): A measure of the extent to which two nuclear spins are coupled. In the simplest cases, it is equal to the distance between adjacent peaks in a split NMR signal. Covalent bond (Section 1.3): Chemical bond between two atoms that results from their sharing of two electrons. Cracking (Section 2.13): A key step in petroleum refining in which high-molecular-weight hydrocarbons are converted to lower molecular-weight ones by thermal or catalytic car￾bon—carbon bond cleavage. Critical micelle concentration (Section 19.5): Concentration above which substances such as salts of fatty acids aggre￾gate to form micelles in aqueous solution. Crown ether (Section 16.4): A cyclic polyether that, via ion—dipole attractive forces, forms stable complexes with metal ions. Such complexes, along with their accompany￾ing anion, are soluble in nonpolar solvents. C terminus (Section 27.7): The amino acid at the end of a pep￾tide or protein chain that has its carboxyl group intact that is, in which the carboxyl group is not part of a peptide bond. Cumulated diene (Section 10.5): Diene of the type CœCœC, in which a single carbon atom participates in double bonds with two others. Cyanohydrin (Section 17.7): Compound of the type Cyanohydrins are formed by nucleophilic addition of HCN to the carbonyl group of an aldehyde or a ketone. Cycloaddition (Section 10.12): Addition, such as the Diels—Alder reaction, in which a ring is formed via a cyclic transition state. Cycloalkane (Section 2.12): An alkane in which a ring of car￾bon atoms is present. Cycloalkene (Section 5.1): A cyclic hydrocarbon characterized by a double bond between two of the ring carbons. Cycloalkyne (Section 9.4): A cyclic hydrocarbon characterized by a triple bond between two of the ring carbons. Cyclohexadienyl anion (Section 23.6): The key intermediate in nucleophilic aromatic substitution by the addition—elimina￾tion mechanism. It is represented by the general structure shown, where Y is the nucleophile and X is the leaving group. RCR W W OH CPN Cyclohexadienyl cation (Section 12.2): The key intermediate in electrophilic aromatic substitution reactions. It is repre￾sented by the general structure where E is derived from the electrophile that attacks the ring. Deactivating substituent (Sections 12.11 and 12.13): A group that when present in place of a hydrogen substituent causes a particular reaction to occur more slowly. The term is most often applied to the effect of substituents on the rate of elec￾trophilic aromatic substitution. Debye unit (D) (Section 1.5): Unit customarily used for mea￾suring dipole moments: 1 D 1  1018 esucm Decarboxylation (Section 19.17): Reaction of the type RCO2H ±£ RH CO2, in which carbon dioxide is lost from a carboxylic acid. Decarboxylation normally occurs readily only when the carboxylic acid is a 1,3-dicarboxylic acid or a -keto acid. Decoupling (Section 13.17): In NMR spectroscopy, any process that destroys the coupling of nuclear spins between two nuclei. Two types of decoupling are employed in 13C NMR spectroscopy. Broadband decoupling removes all the 1 H—13C couplings; off-resonance decoupling removes all of 1 H—13C couplings except those between directly bonded atoms. Dehydration (Section 5.9): Removal of H and OH from adja￾cent atoms. The term is most commonly employed in the preparation of alkenes by heating alcohols in the presence of an acid catalyst. Dehydrogenation (Section 5.1): Removal of the elements of H2 from adjacent atoms. The term is most commonly en￾countered in the industrial preparation of ethylene from ethane, propene from propane, 1,3-butadiene from butane, and styrene from ethylbenzene. Dehydrohalogenation (Section 5.14): Reaction in which an alkyl halide, on being treated with a base such as sodium ethoxide, is converted to an alkene by loss of a proton from one carbon and the halogen from the adjacent carbon. Delocalization (Section 1.9): Association of an electron with more than one atom. The simplest example is the shared E H H H H H H Y X  H H H H H

GLOSSARY G-8 electron pair(covalent)bond Delocalization is important in Dipole-tipole attraction(Section 2.14): A force of attraction onjugated T electron systems, where an electron may be between oppositely polarized atoms. ssociated with several carbon atoms Dipole/induced-dipole attraction(Section 4.5): A force of at- Deoxy sugar (Section 25.10): A carbohydrate in which one of traction that results when a species with a permanent dipole EPT (Section 13. 18): Abbreviation for distortionless enhance- induces a complementary dipole in a second species Dipole moment(Section 1.5): Product of the attractive force ment of polarization transfer. DEPT is an NMR technique between two opposite charges and the distance between that reveals the number of hydrogens directly attached to a them. Dipole moment has the symbol u and is measured in carbon responsible for a particular signal Debye units( D). Detergents(Section 195): Substances that clean by micellar Disaccharide (Sections 25.1 and 25. 14): A carbohydrate that action. Although the term usually refers to a synthetic de- yields two monosaccharide units(which may be the same tergent, soaps are also detergents or different) on hydrolysis Diastereomers( Section 7. 10): Stereoisomers that are not enan- Dispersion force (Section 2. 14): See induced-dipole/induced tiomers stereoisomers that are not mirror images of one dipole attrac another substituted alkene ( Section 5.6): Alkene of the type Diastereotopic(Section 13.6): Describing two atoms or groups H, or rCh R may be the same a molecule that are attached to the same atom but are in or different, they may be any length, and they may be stereochemically different environments that are not mirror branched or unbranched. The significant point is that there mages of each other. The two protons shown in bold in are two carbons directly bonded to the carbons of the dou CH2=CHCl, for example, are diastereotopic. One is cis to ble bone Disulfide bridge(Section 27.7): An S-S bond between the 1, 3-Diaxial repulsion(Section 3. 8): Repulsive forces between sulfur atoms of two cysteine residues in a peptide or protein axial substituents on the same side of a cyclohexane ring. DNA (deoxyribonucleic acid)(Section 27. 26): A polynu- Diazonium ion (Sections 22.16-22.17): lon of the type cleotide of 2 -deoxyribose present in the nuclei of cells that R-NEN: Aryl diazonium ions are formed by treatment serves to store and replicate genetic information. Genes are of primary aromatic amines with nitrous acid. They are ex DNA tremely useful in the preparation of aryl halides, phenols, Double bond (Section 1. 4): Bond formed by the sharing of Diazotization(Section 22.17): The reaction by which a pri Double dehydrohalogenation(Section 9.7): Reaction in mary arylamine is converted to the corresponding diazo- which a geminal dihalide or vicinal dihalide, on being nium ion by nitrosation. treated with a very strong base such as sodium amide, is Dieckmann reaction(Section 21.2 ): An intramolecular version converted to an alkyne by loss of two protons and the twe of the claisen condensation halogen substituents. Dielectric constant(Section 8. 12): A measure of the ability of a Double helix (Section 27. 27) The form in which DNA nor- material to disperse the force of attraction between oppositely mally occurs in living systems. Two complementary strands charged particles. The symbol for dielectric constant ise of DNA are associated with each other by hydrogen bonds Diels-Alder reaction (Section 10.12): Conjugate addition of an between their base pairs, and each DNA strand adopts a alkene to a conjugated diene to give a cyclohexene deriva helical shape tive. Diels-Alder reactions are extremely useful in synthesis Section 13.4): The low-field region of an NMR Dienophile (Section 10.12): The alkene that adds to the diene n. a signal that is downfield with respect to another a Diels-Alder re left on the spectrum. B-Diketone (Section 18.5): Compound of the tyr Eclipsed conformation ( Section 3.1): Conformation in which bonds on adjacent atoms are aligned with one another. For example, the C-H bonds indicated in the structure sho Dimer (Section 6.21): Molecule formed by the combination of two identical molecules Dipeptide (Section 27.7): A compound in which two a-an acids are linked by an amide bond between the amino group of one and the carboxyl group of the other Edman degradation(Section 27. 13): Method for determining the N-terminal amino acid of a peptide or protein. It in- RCHC— NHCHCO volves treating the material with phenyl isothiocyanate NH R (CHSN=C=S), cleaving with acid, and then identifying the phenylthiohydantoin(PTH derivative) produced Forward Main Menu TOC Study Guide Toc Student OLCMHHE Website

GLOSSARY G-8 electron pair (covalent) bond. Delocalization is important in conjugated electron systems, where an electron may be associated with several carbon atoms. Deoxy sugar (Section 25.10): A carbohydrate in which one of the hydroxyl groups has been replaced by a hydrogen. DEPT (Section 13.18): Abbreviation for distortionless enhance￾ment of polarization transfer. DEPT is an NMR technique that reveals the number of hydrogens directly attached to a carbon responsible for a particular signal. Detergents (Section 19.5): Substances that clean by micellar action. Although the term usually refers to a synthetic de￾tergent, soaps are also detergents. Diastereomers (Section 7.10): Stereoisomers that are not enan￾tiomers stereoisomers that are not mirror images of one another. Diastereotopic (Section 13.6): Describing two atoms or groups in a molecule that are attached to the same atom but are in stereochemically different environments that are not mirror images of each other. The two protons shown in bold in CH2œCHCl, for example, are diastereotopic. One is cis to chlorine, the other is trans. 1,3-Diaxial repulsion (Section 3.8): Repulsive forces between axial substituents on the same side of a cyclohexane ring. Diazonium ion (Sections 22.16—22.17): Ion of the type . Aryl diazonium ions are formed by treatment of primary aromatic amines with nitrous acid. They are ex￾tremely useful in the preparation of aryl halides, phenols, and aryl cyanides. Diazotization (Section 22.17): The reaction by which a pri￾mary arylamine is converted to the corresponding diazo￾nium ion by nitrosation. Dieckmann reaction (Section 21.2): An intramolecular version of the Claisen condensation. Dielectric constant (Section 8.12): A measure of the ability of a material to disperse the force of attraction between oppositely charged particles. The symbol for dielectric constant is . Diels—Alder reaction (Section 10.12): Conjugate addition of an alkene to a conjugated diene to give a cyclohexene deriva￾tive. Diels—Alder reactions are extremely useful in synthesis. Dienophile (Section 10.12): The alkene that adds to the diene in a Diels—Alder reaction. -Diketone (Section 18.5): Compound of the type also referred to as a 1,3-diketone. Dimer (Section 6.21): Molecule formed by the combination of two identical molecules. Dipeptide (Section 27.7): A compound in which two -amino acids are linked by an amide bond between the amino group of one and the carboxyl group of the other: RCHC±NHCHCO2  W NH3 W R O X R O O R R±NPN Dipole—dipole attraction (Section 2.14): A force of attraction between oppositely polarized atoms. Dipole/induced-dipole attraction (Section 4.5): A force of at￾traction that results when a species with a permanent dipole induces a complementary dipole in a second species. Dipole moment (Section 1.5): Product of the attractive force between two opposite charges and the distance between them. Dipole moment has the symbol  and is measured in Debye units (D). Disaccharide (Sections 25.1 and 25.14): A carbohydrate that yields two monosaccharide units (which may be the same or different) on hydrolysis. Dispersion force (Section 2.14): See induced-dipole/induced￾dipole attraction. Disubstituted alkene (Section 5.6): Alkene of the type R2CœCH2 or RCHœCHR. The groups R may be the same or different, they may be any length, and they may be branched or unbranched. The significant point is that there are two carbons directly bonded to the carbons of the dou￾ble bond. Disulfide bridge (Section 27.7): An S±S bond between the sulfur atoms of two cysteine residues in a peptide or protein. DNA (deoxyribonucleic acid) (Section 27.26): A polynu￾cleotide of 2-deoxyribose present in the nuclei of cells that serves to store and replicate genetic information. Genes are DNA. Double bond (Section 1.4): Bond formed by the sharing of four electrons between two atoms. Double dehydrohalogenation (Section 9.7): Reaction in which a geminal dihalide or vicinal dihalide, on being treated with a very strong base such as sodium amide, is converted to an alkyne by loss of two protons and the two halogen substituents. Double helix (Section 27.27) The form in which DNA nor￾mally occurs in living systems. Two complementary strands of DNA are associated with each other by hydrogen bonds between their base pairs, and each DNA strand adopts a helical shape. Downfield (Section 13.4): The low-field region of an NMR spectrum. A signal that is downfield with respect to another lies to its left on the spectrum. Eclipsed conformation (Section 3.1): Conformation in which bonds on adjacent atoms are aligned with one another. For example, the C±H bonds indicated in the structure shown are eclipsed. Edman degradation (Section 27.13): Method for determining the N-terminal amino acid of a peptide or protein. It in￾volves treating the material with phenyl isothiocyanate (C6H5NœCœS), cleaving with acid, and then identifying the phenylthiohydantoin (PTH derivative) produced. H H

G-9 GLOSSARY Elastomer(Section 10. 11): A synthetic polymer that possesses aryne intermediate In the second stage, nucleophilic addi- tion to the aryne yields the product of the reaction. Electromagnetic radiation(Section 13. 1): Various forms of ra- Elimination bimolecular (E2)mechanism (Section 5.15): diation propagated at the speed of light. Electromagnetic Mechanism for elimination of alkyl halides characterized radiation includes (among others) visible light; infrared, ul- by a transition state in which the attacking base rer traviolet and microwave radiation: and radio waves. cos- proton at the same time that the bond to the halide leaving group is broken. Electron affinity(Section 1. 2): Energy change associated with Elimination unimolecular (E1)mechanism(Section 5.17 the capture of an electron by an atom Mechanism for elimination characterized by the slow for Electronegativity (Section 1.5): A measure of the ability of an mation of a carbocation intermediate followed by rapid loss atom to attract the electrons in a covalent bond toward it- of a proton from the carbocation to form the alkene. self. Fluorine is the most electronegative element. Enamine (Section 17. 11): Product of the reaction of a sec- Electronic effect (Section 5.6): An effect on structure or reac- ondary amine and an aldehyde or a ketone. Enamines ar tivity that is attributed to the change in electron distribution characterized by the general structure that a substituent causes in a molecule Electron impact (Section 13. 21): Method for producing posi- C=CR tive ions in mass spectrometry whereby a molecule is bom- 18-Electron rule(Section 14. 14): The number of ligands that Enantiomeric excess(Section 7.4): Difference between the can be attached to a transition metal are such that the sum of percentage of the major enantiomer present in a mixtur and the percentage of its mirror image. An optically pure trons of the metal equals 18 material has an enantiomeric excess of 100%o. A racemi Electrophile (Section 4.10): A species(ion or compound) that mixture has an enantiomeric excess of zero an act as a Lewis acid, or electron pair acceptor; an"elec- Enantiomers(Section 7. 1): Stereoisomers that are related as an tron seeker " Carbocations are one type of electrophile bject and its nonsuperimposable mirror image Electrophilic addition(Section 6. 4): Mechanism of addition in Enantioselective synthesis(Section 27. 4): Reaction that con- which the species that first attacks the multiple bond is an verts an achiral or racemic starting material to a chiral prod electrophile("electron seeker") uct in which one enantiomer is present in excess of the Electrophilic aromatic substitution (Section 12.1): Fundamen- tal reaction type exhibited by aromatic compounds. An Enantiotopic(Section 13.6): Describing two atoms or groups electrophilic species(Et)attacks an aromatic ring and re- in a molecule whose environments are nonsuperposable places one of the hydrogens mirror images of each other. The two protons shown in bold Ar-H+E—Y—)Ar-E+H-Y in CHa CH,Cl, for example, are enantiotopic. Replacement of first one, then the other, by some arbitrary test group Electrophoresis(Section 27.3): Method for separating sub- yields compounds that are enantiomers of each other. stances on the basis of their tendency to migrate to a posi Endothermic(Section 1. 2): Term describing a process or reac- tively or negatively charged electrode at a particular pH Electrostatic attraction ( Section 1.2): Force of attraction be Enediyne antibiotics(Section 9.4): A family of tumor-inhibit tween oppositely charged part ing substances that is characterized by the presence of a Electrostatic potential (Section 1.10): The energy of interac C≡C-C=C-C≡ C unit as part of a nine- or ten tion between a point positive charge and the charge field of membered ring. a molecule. The electrostatic potential is positive for the in- Energy of activation(Section 3. 2): Minimum energy that a re teraction between the point positive charge and the mole acting system must possess above its most stable state in or cules electrons and negative for the interaction er to undergo a chemical or structural change nuclei Enol (Section 9.12): Compound of the type Elementary step(Section 4.7): A step in a reaction in which each species shown in the equation fo participates in the same transition state. An eleme is characterized by a single transition state. Elements of unsaturation: See index of hydrogen deficiency. Enols are in equilibrium with an isomeric aldehyde or ke B-Elimination (Section 5.8): Reaction in which a double of tone, but are normally much less stable than aldehydes and ent atoms(See dehydration, dehydrogenation, dehydro. Enolate ion( Section 18.6): The conjugate base of an enol halogenation, and double dehydrohalogenation.) Enolate ions are stabilized by electron delocalization Elimination-addition mechanism(Section 23.8): Two-stage first stage, an aryl halide undergoes elimination to form the mechanism for nucleophilic aromatic substitution. In RC=CR2<>RC-CR? Forward Main Menu TOC Study Guide Toc Student OLCMHHE Website

G-9 GLOSSARY Elastomer (Section 10.11): A synthetic polymer that possesses elasticity. Electromagnetic radiation (Section 13.1): Various forms of ra￾diation propagated at the speed of light. Electromagnetic radiation includes (among others) visible light; infrared, ul￾traviolet, and microwave radiation; and radio waves, cos￾mic rays, and X-rays. Electron affinity (Section 1.2): Energy change associated with the capture of an electron by an atom. Electronegativity (Section 1.5): A measure of the ability of an atom to attract the electrons in a covalent bond toward it￾self. Fluorine is the most electronegative element. Electronic effect (Section 5.6): An effect on structure or reac￾tivity that is attributed to the change in electron distribution that a substituent causes in a molecule. Electron impact (Section 13.21): Method for producing posi￾tive ions in mass spectrometry whereby a molecule is bom￾barded by high-energy electrons. 18-Electron rule (Section 14.14): The number of ligands that can be attached to a transition metal are such that the sum of the electrons brought by the ligands plus the valence elec￾trons of the metal equals 18. Electrophile (Section 4.10): A species (ion or compound) that can act as a Lewis acid, or electron pair acceptor; an “elec￾tron seeker.” Carbocations are one type of electrophile. Electrophilic addition (Section 6.4): Mechanism of addition in which the species that first attacks the multiple bond is an electrophile (“electron seeker”). Electrophilic aromatic substitution (Section 12.1): Fundamen￾tal reaction type exhibited by aromatic compounds. An electrophilic species (E) attacks an aromatic ring and re￾places one of the hydrogens. Electrophoresis (Section 27.3): Method for separating sub￾stances on the basis of their tendency to migrate to a posi￾tively or negatively charged electrode at a particular pH. Electrostatic attraction (Section 1.2): Force of attraction be￾tween oppositely charged particles. Electrostatic potential (Section 1.10): The energy of interac￾tion between a point positive charge and the charge field of a molecule. The electrostatic potential is positive for the in￾teraction between the point positive charge and the mole￾cule’s electrons and negative for the interaction with the nuclei. Elementary step (Section 4.7): A step in a reaction mechanism in which each species shown in the equation for this step participates in the same transition state. An elementary step is characterized by a single transition state. Elements of unsaturation: See index of hydrogen deficiency. -Elimination (Section 5.8): Reaction in which a double or triple bond is formed by loss of atoms or groups from adja￾cent atoms. (See dehydration, dehydrogenation, dehydro￾halogenation, and double dehydrohalogenation.) Elimination—addition mechanism (Section 23.8): Two-stage mechanism for nucleophilic aromatic substitution. In the first stage, an aryl halide undergoes elimination to form an Ar±H E ±Y Ar±E H ±Y aryne intermediate. In the second stage, nucleophilic addi￾tion to the aryne yields the product of the reaction. Elimination bimolecular (E2) mechanism (Section 5.15): Mechanism for elimination of alkyl halides characterized by a transition state in which the attacking base removes a proton at the same time that the bond to the halide leaving group is broken. Elimination unimolecular (E1) mechanism (Section 5.17): Mechanism for elimination characterized by the slow for￾mation of a carbocation intermediate followed by rapid loss of a proton from the carbocation to form the alkene. Enamine (Section 17.11): Product of the reaction of a sec￾ondary amine and an aldehyde or a ketone. Enamines are characterized by the general structure Enantiomeric excess (Section 7.4): Difference between the percentage of the major enantiomer present in a mixture and the percentage of its mirror image. An optically pure material has an enantiomeric excess of 100%. A racemic mixture has an enantiomeric excess of zero. Enantiomers (Section 7.1): Stereoisomers that are related as an object and its nonsuperimposable mirror image. Enantioselective synthesis (Section 27.4): Reaction that con￾verts an achiral or racemic starting material to a chiral prod￾uct in which one enantiomer is present in excess of the other. Enantiotopic (Section 13.6): Describing two atoms or groups in a molecule whose environments are nonsuperposable mirror images of each other. The two protons shown in bold in CH3CH2Cl, for example, are enantiotopic. Replacement of first one, then the other, by some arbitrary test group yields compounds that are enantiomers of each other. Endothermic (Section 1.2): Term describing a process or reac￾tion that absorbs heat. Enediyne antibiotics (Section 9.4): A family of tumor-inhibit￾ing substances that is characterized by the presence of a CPC±CœC±CPC unit as part of a nine- or ten￾membered ring. Energy of activation (Section 3.2): Minimum energy that a re￾acting system must possess above its most stable state in or￾der to undergo a chemical or structural change. Enol (Section 9.12): Compound of the type Enols are in equilibrium with an isomeric aldehyde or ke￾tone, but are normally much less stable than aldehydes and ketones. Enolate ion (Section 18.6): The conjugate base of an enol. Enolate ions are stabilized by electron delocalization. RCœCR2 W O RC±CR2  O O RCœCR2 W OH R2CœCR W NR 2

GLOSSARY Enthalpy (Section 2. 15): The heat content of a substance; sym- notation. when higher ranked substituents are on side of the double bond the configuration is Z whe Envelope (Section 3.10): One of the two most stable ranked substituents are on opposite sides, the confi mations of cyclopentane. Four of the carbons in th is E. Rank is determined by the Cahn-ngold-Prelog sys- lope conformation are coplanar; the fifth carbon lies tem or below this plane. Enzyme (Section 27. 20): A protein that catalyzes a chemical re- Fats and oils(Section 26.2): Triesters of glycerol. Fats are action in a living system Epimers (Section 25. 21): Diastereomers that differ in configu- solids at room temperature, oils are liquids. ration at only one of their stereogenic centers. Fatty acid(Section 26.2): Carboxylic acids obtained by hydrol- Epoxidation (Section 6. 18): Conversion of an alkene to an ysis of fats and oils. Fatty acids typically have unbranched chains and contain an even number of carbon atoms in the epoxide by treatment with a peroxy acid. range of 12-20 carbons. They may include one or more Epoxide(Section 6. 18): Compound of the type R2C、CR2 Fatty acid synthetase( Section 26.3): Complex of enzymes hat catalyzes the biosynthesis of fatty acids from acetate Field effect ( Section 19.6): An electronic effect in a molecule Equatorial bond 3.6): a bond to a carbon in the chair hat is transmitted from a substituent to a reaction site via conformation exane oriented approximately along the medium(e. g, solvent) ingerprint region (Section 13. 19): The region 1400-625 cm of an infrared spectrum. This region is less character istic of functional groups than others, but varies so much from one molecule to another that it can be used to deter- mine whether two substances are identical or not Erythro (Section 7. 11): Term applied to the relative configura- Fischer esterification (Sections 15.8 and 19.14): Acid-cat tion of two stereogenic centers within a molecule. The alyzed ester formation between an alcohol and a carboxylic erythro stereoisomer has like substituents on the same side of a Fischer projection. Essential amino acids (Section 27. 1): amino acids that must be present in the diet for normal growth and good health. RCOH+ ROH RCOR′+H2O Essential fatty acids( Section 26.6): Fatty acids that must be present in the diet for normal growth and good health Fischer projection (Section 7.7): Method for representing Essential oils( Section 26.7): Pleasant-smelling oils of plants stereochemical relationships. The four bonds to a ste- consisting of mixtures of terpenes, esters, alcohols, and neogenic carbon are represented by a cross. The horizontal other volatile organic substances. bonds are understood to project toward the viewer and the Ester (Sections 2.3 and 20.1): Compound of the type RCOR v一C= y in a Fischer projection as Estrogen (Section 26.15 ) A female sex hormone Ethene(Section 5. I ) IUPAC name for CH2-CH2. The com- Formal charge(Section 1.6): The charge, either positiv the IUPAC rules permit its use. negative, on an atom calculated by subtracting from the number of valence electrons in the neutral atom a number Ether(Section 16. 1): Molecule that contains a C-o-C unit h as ROR, ROAr, or ArOAr. When the two groups equal to the sum of its unshared electrons plus half the elec- trons in its covalent bonds bonded to oxygen are the same, the ether is described as a Fragmentation pattern (Section 13. 21): In mass spectrometry, symmetrical ether: When the groups are different, it is the ions produced by dissociation of the molecular ion alled a mixed ether. Ethylene( Section 5.1): CH2-CH2, the simplest alkene and Free energy (Section 3.8): The available energy of a system symbol, the most important industrial organic chemical Ethyl group(Section 2.10): The group CHa CH2- Free radical (Section 4.17): Neutral species in which one of the Exothermic (Section 1.2): Term describing a reaction electrons in the valence shell of carbon is unpaired. An ex ample is methyl radical, CH3 process that gives off heat. Extinction coefficient: See molar absorptivity. Frequency(Section 13. 1): Number of waves per unit time. Al- E-Z notation for alkenes( Section 5.4): System for specifying though often expressed in hertz(Hz), or cycles per second, the si unit for frequency is s double-bond configuration that is an alternative to cis-trans Forward Main Menu TOC Study Guide Toc Student OLCMHHE Website

GLOSSARY G-10 Enthalpy (Section 2.15): The heat content of a substance; sym￾bol, H. Envelope (Section 3.10): One of the two most stable confor￾mations of cyclopentane. Four of the carbons in the enve￾lope conformation are coplanar; the fifth carbon lies above or below this plane. Enzyme (Section 27.20): A protein that catalyzes a chemical re￾action in a living system. Epimers (Section 25.21): Diastereomers that differ in configu￾ration at only one of their stereogenic centers. Epoxidation (Section 6.18): Conversion of an alkene to an epoxide by treatment with a peroxy acid. Epoxide (Section 6.18): Compound of the type Equatorial bond (Section 3.6): A bond to a carbon in the chair conformation of cyclohexane oriented approximately along the equator of the molecule. Erythro (Section 7.11): Term applied to the relative configura￾tion of two stereogenic centers within a molecule. The erythro stereoisomer has like substituents on the same side of a Fischer projection. Essential amino acids (Section 27.1): Amino acids that must be present in the diet for normal growth and good health. Essential fatty acids (Section 26.6): Fatty acids that must be present in the diet for normal growth and good health. Essential oils (Section 26.7): Pleasant-smelling oils of plants consisting of mixtures of terpenes, esters, alcohols, and other volatile organic substances. Ester (Sections 2.3 and 20.1): Compound of the type Estrogen (Section 26.15): A female sex hormone. Ethene (Section 5.1): IUPAC name for CH2œCH2. The com￾mon name ethylene, however, is used far more often, and the IUPAC rules permit its use. Ether (Section 16.1): Molecule that contains a C±O±C unit such as ROR, ROAr, or ArOAr. When the two groups bonded to oxygen are the same, the ether is described as a symmetrical ether. When the groups are different, it is called a mixed ether. Ethylene (Section 5.1): CH2œCH2, the simplest alkene and the most important industrial organic chemical. Ethyl group (Section 2.10): The group CH3CH2±. Exothermic (Section 1.2): Term describing a reaction or process that gives off heat. Extinction coefficient: See molar absorptivity. E—Z notation for alkenes (Section 5.4): System for specifying double-bond configuration that is an alternative to cis—trans RCOR O X R2C O CR2 notation. When higher ranked substituents are on the same side of the double bond, the configuration is Z. When higher ranked substituents are on opposite sides, the configuration is E. Rank is determined by the Cahn—Ingold—Prelog sys￾tem. Fats and oils (Section 26.2): Triesters of glycerol. Fats are solids at room temperature, oils are liquids. Fatty acid (Section 26.2): Carboxylic acids obtained by hydrol￾ysis of fats and oils. Fatty acids typically have unbranched chains and contain an even number of carbon atoms in the range of 12—20 carbons. They may include one or more double bonds. Fatty acid synthetase (Section 26.3): Complex of enzymes that catalyzes the biosynthesis of fatty acids from acetate. Field effect (Section 19.6): An electronic effect in a molecule that is transmitted from a substituent to a reaction site via the medium (e.g., solvent). Fingerprint region (Section 13.19): The region 1400—625 cm1 of an infrared spectrum. This region is less character￾istic of functional groups than others, but varies so much from one molecule to another that it can be used to deter￾mine whether two substances are identical or not. Fischer esterification (Sections 15.8 and 19.14): Acid-cat￾alyzed ester formation between an alcohol and a carboxylic acid: Fischer projection (Section 7.7): Method for representing stereochemical relationships. The four bonds to a ste￾reogenic carbon are represented by a cross. The horizontal bonds are understood to project toward the viewer and the vertical bonds away from the viewer. Formal charge (Section 1.6): The charge, either positive or negative, on an atom calculated by subtracting from the number of valence electrons in the neutral atom a number equal to the sum of its unshared electrons plus half the elec￾trons in its covalent bonds. Fragmentation pattern (Section 13.21): In mass spectrometry, the ions produced by dissociation of the molecular ion. Free energy (Section 3.8): The available energy of a system; symbol, G. Free radical (Section 4.17): Neutral species in which one of the electrons in the valence shell of carbon is unpaired. An ex￾ample is methyl radical, . Frequency (Section 13.1): Number of waves per unit time. Al￾though often expressed in hertz (Hz), or cycles per second, the SI unit for frequency is s1 . CH3 x w y z C x z w y is represented in a Fischer projection as RCOH ROH H2O O X RCOR O X H