A ring that contains at least one heteroatom (an atom other than carbon) is called a heterocycle, and a substance based on a heterocyclic ring is a heterocyclic compound. Heterocyclic compounds containing N, O or S are by far the most common

Esters, like aldehydes and ketones, are weakly acidic. When an ester with an alpha hydrogen is treated with one equivalent of a base such as sodium ethoxide, a reversible condensation reaction occurs to yield a β−keto ester product. This reaction between two ester components is known as the Claisen condensation reaction

Compounds were classified as being either aliphatic or aromatic in the latter part of the nineteenth century. To be classified as aliphatic meant then that the chemical behavior of a compound was “fatlike”. To be classified as aromatic meant then that the compound had a low hydrogen/carbon ratio and that it was “fragrant

A UV-Vis spectrophotometer measures the amount of light absorbed at each wavelength of the UV and visible regions of the electromagnetic spectrum. λmax— the wavelength of maximum absorption

A hydrocarbon whose molecules contain two double bonds is called an alkadiene(alkatriene for three double bonds); A hydrocarbon with two triple bonds is called an alkadiyne; A hydrocarbon with a double and triple bond is called an alkenyne

Conjugated unsaturated systems have a p orbital on a carbon adjacent to a double bond The p orbital can come from another double or triple bond The p orbital may be the empty p orbital of a carbocation or a p orbital with a single electron in it (a radical)

The reactivity of organometallic compounds increases with the percent ionic character of the carbon-metal bond. RLi and RMgX are of great importance in organic synthesis

The C—X bond of alkyl halides is polarized. The carbon atom bears a partial positive charge, The halogen atom a partial negative charge

Aldehydes are named by replacing the terminal –e of the corresponding alkane name with –al. The longest chain selected as the base name must contain the –CHO group, and the –CHO carbon is always numbered as carbon 1

More reactive than benzene toward electrophilic substitution NO2 An deactivating group Less reactive than benzene toward electrophilic substitution Ortho-para director Meta director