21-1 Naming the Amines CHAPTER 21 ehesme8haompnR9roaesnaggn2anon Amines and Their Derivatives: Functional Groups Containing Nitrogen g rennah .b CH H 卧 Substancesonnw amine unctionsarecalled mnes H.N 入NH HN 入N 代 2 21-2 Structural and Physical Properties of Amines 外bgah2g点h-hunconal The alkanamine molecule is tetrahedral. CICCCC 入人 11 CHAPTER 21 Amines and Their Derivatives: Functional Groups Containing Nitrogen 21-1 Naming the Amines Amines are related to ammonia in the same sense that ethers and alcohols are related to water. In the amines, the number of –R groups on the nitrogen atom defines the designation of primary, secondary and tertiary. Aliphatic amines are named as alkanamines according to Chem Abstracts. The name of the alkane stem is modified by replacing the ending –e with –amine. The position of the functional group is indicated, as in alcohols, by prefixing the carbon atom to which it is attached. Substances containing two amine functions are called diamines: Aromatic amines (or anilines) are called benzenamines. For secondary and tertiary amines, the largest alkyl substituent on nitrogen is chosen as the alkanamine stem. Other groups are named using N-, followed by the name of the additional substituent(s). An alternate naming convention is to treat the amino- functional group as a substituent of the alkane stem. 21-2 Structural and Physical Properties of Amines The alkanamine molecule is tetrahedral. The nitrogen orbitals in amines are very nearly sp3 hybridized. The term pyramidal is often used to describe the geometry of the nitrogen atom and its three substituents