Improved method of making nevirapine

A process for making nevirapine, comprising the following steps:(a) reacting a 2-halo-3-pyridinecarbonitrile of the formulawherein X is a fluorine, chlorine, bromine or iodine atom, preferably chlorine or bromine, with cyclopropylamine, to yield 2-(cyclopropylamino)-3-pyridinecarbonitrile;(b) hydrolyzing the 2-(cyclopropylamino)-3-pyridinecarbonitrile to yield 2-(cyclopropylamino)-3-pyridine carboxylic acid;(c) isolating the 2-(cyclopropylamino)-3-pyridine carboxylic acid from the reaction medium;(e) treating the 2-(cyclopropylamino)-3-pyridine carboxylic acid with a chlorinating agent, to yield 2-(cyclopropylamino)-3-pyridinecarbonyl chloride;(f) reacting the 2-(cyclopropylamino)-3-pyridine carbonyl chloride with a 2-halo-4-methyl-3-pyridinamine of the formulawherein X is a fluorine, chlorine, bromine or iodine atom, preferably chlorine or bromine, to produce an N-(2-halo-4-methyl-3-pyridinyl)-2-(cyclopropylamino)-3-pyridinecarboxamide; and (g) cyclizing the N-(2-halo-4-methyl-3-pyridinyl)-2-(cyclopropylamino)-3-pyridinecarboxamide by treatment with a strong base, to yield nevirapine.