Dication C(R-1)-N(R-2)(2) synthons and their use in the synthesis of formamidines, amidines, and alpha-aminonitriles

A combination of amides and 2-pyridinesulfonyl chloride was evaluated as sy nthons of the dication C(R-1)-N(R-2)(2)(2+). When the substrates were prima ry amines, high yields of formamidines and amidines were obtained. When the substrates were alpha-aminoamides, alpha-aminonitriles were obtained. Thro ugh this process, naturally occurring a-aminoacids can be transformed into chiral alpha-aminonitriles with complete retention of stereochemical config uration. All reactions proceed rapidly at room temperature, and normally fi nish within 10 min, with yields ranging from 80 to 95% for most cases. Amon g the sulfonyl chlorides examined, 2-pyridinesulfonyl chloride stands out i n both reaction rate and selectivity of formamidine or amidine versus sulfo nyl amide. The scope and limitations of the reaction among different types of amides as synthons and amines as substrates were examined. (C) 2000 Else vier Science Ltd. All rights reserved.