Synthesis of Hexahydro-3,3,5,5,7-pentaalkyl-2H-1,4-diazepin-2-ones from 1,3-Diamines and Ketones

Article abstract of DOI:10.1021/jo00315a020

A new method for preparing mono- and bis(hexahydro-3,3,5,5,7-pentaalkyl-2H-1,4-diazepin-2-ones) is reported (Schemes I and II).The key step of this synthesis is the final one in which a 1,3-diamine is reacted with a ketone in the presence of sodium hydroxide, chloroform, and a phase-transfer catalyst (PTC).Bis(hexahydro-3,3,5,5,7-pentaalkyl-2H-1,4-diazepin-2-ones) are isolated as a mixture of diastereomers.Of these bis compounds, diastereomers of 1,1'-(1,2-ethanediyl)bis(hexahydro-3,3,5,5,7-pentamethyl-2H-1,4-diazepin-2-one) (5a) can be readily separated by a fractional recrystallization, or their diastereomeric distributions can be measured by 13C NMR.