Aldol derivatives of 5-phenyl-1,4-benzodiazepin-2-on-N4-oxide; intriguing inertness of N-oxides in aldol reactions

Abstract

In an attempt to prepare 3-substituted 7-chloro-1,3-dihydro-1-methyl-5-phenyl-2H-1,4-benzodiazepin-2-on-N 4 -oxides 7-10, C(3) carbanion of 5-phenyl-1,4-benzodiazepin-2-on-N 4 -oxide (2) proved completely inert in aldol reaction: Detour to the target compounds 7-10 via aldols 3-6 was required. Unexpected inertness of C(3) carbanion of 2 was attributed to the high charge delocalization.