Lecture 25 Amine nomenclature Basicity of amines Synthesis of amines (on board)

Nomenclature of Aldehydes & Ketones: IUPAC Rules Functional GroupSuffix if highest priority groupAs a substituent CO 2 H carboxylic acid-oic acid-carboxy- CO 2 R ester-oate-alkoxycarbonyl- CO 2 NR 2 amide-amide-carbamoyl- CHO aldehyde-al-oxo- CRO ketone-one-oxo- OH alcohol-ol-hydroxy- NR 2 amine-amine-amino- SH thiol-thiol-mercapto-

Nomenclature of Primary Amines: IUPAC A. Primary Amines 1. Find the longest chain to contain the -NH 2 group; this is the parent chain. 2. This parent chain’s name ends in ‘amine’ - the suffix. E.g., take alkane and convert to alkanamine. 3. Number the parent chain such that the carbon bearing the -NH 2 has the lowest number possible. Give location of -NH 2 group in name. 4. Give name; be sure to list substituents alphabetically and to give their location; these are the prefixes. Remember that sec-, tert-, o-, m-, p-, di-, tri-, tetra- are not considered when alphabetizing, but iso is. Name the following:

Nomenclature of Primary Amines: Common Name Primary Amines If the primary amine is a simple structure, that is the carbon group is simple, then the common name is easy to determine. In the common name, the amine’s name is “alkyl amine”; two words. Name the following:

Nomenclature of 2° & 3° Amines: IUPAC B. 2° & 3° Amines 1. Find the longest R group chain to contain the -NR 2 /-NHR group; this is the parent chain. The carbon of the parent chain that’s bound to the N gets the #1 designation. 2. This parent chain’s name ends in ‘amine’ - the suffix. E.g., take alkane and convert to alkanamine. 3. The other R groups are listed first (as the first word) and alphabetically with an “N-” in front of them to designate that the R group is bound to the nitrogen. (Similar to 2° and 3° amide nomenclature.) 4. Give name; be sure to list the parent chain substituents alphabetically and to give their location; these are the prefixes. Remember that sec-, tert-, o-, m-, p-, di-, tri-, tetra- are not considered when alphabetizing, but iso is. Name the following:

Nomenclature of 2° & 3° Amines: Common Name B. 2° & 3° Amines 1. Identify the R groups bound to nitrogen. 2. List the alkyl groups alphabetically. Remember not to alphabetize di-, tri-, sec-, or -tert. 3. End the name with the word “amine”. Name the following:

Nomenclature: Heterocyclic Amines Parent names of some heterocyclic amines: Name the following:

Basicity of Amines Basicity of amines dominates its chemistry. Measure of basicity is pK b :

Basicity of Amines The lower the pK b value, the more basic the amine. pK b values are related to the pK a values of the conjugate acids: pK a + pK b = 14 Example: NH 3 has a pK b = 4.74, so the pK a of its conjugate acid, NH 4 + is It is common to find the pK a for the ammonium salt; then need to convert to pK b. Unlike carboxylic acids, the effect of the R substituents on the nitrogen’s basicity is minimal except for aniline derivatives.