Studies on lactams—VII

Abstract

Abstract A synthesis of β-amino-β-lactams has been achieved by the cyclo-addition of diphenylketene and N,N,N′-trisubstituted amidines. Since these β-lactams undergo facile decomposition in presence of a trace of moisture, their purification proved very difficult. However, it was possible to isolate four crystallinegb-amino-β-lactams. The hydrolysis of 3,3-diphenyl-4-amino-2-azetidinones proceeds along a different path from that of 3,3-dialkyl-4-amino-2 azetidinones. A mechanism involving the formation of a carbanion on carbon 3 stabilized by two phenyl groups is suggested.