Convenient preparations of imines and symmetrical secondary amines possessing primary or secondary alkyl groups

Abstract

Hindered alkyl aldehydes react with benzotriazole and ammonia in dry ethanol or methanol to yield the corresponding bis[1-(benzotriazol-1-yl)alkyl]amines 2. The reaction of aryl aldehydes, however, yields 1-(benzotriazol-1-yl)-N-alkylidenealkylamines 3. The reactions of adducts 2 and 3 with lithium aluminum hydride furnishes dialkyl- and dibenzylamine derivatives 4. Although the reactions of 2 and 3 with organometallic reagents are not as general, in several cases the reactions of amines 2 with Grignard reagents yield 1-alkyl or aryl substituted N-alkylidenealkylamines 5. Similar reactions of amines 2 with phenyl lithium afford 1,1'-diphenyldialkylamines 7.