Ab initio study of syn and anti structures of N-nitroso compounds containing a carbonyl group

Abstract

A variety of ab initio molecular orbital methods, RHF, MP2 and B3LYP, have been applied to N-methyl- N-nitrosourea ( 1), N-methyl- N-nitrosoacetamide ( 2) and N-methyl- N-nitrosomethylcarbamate ( 3) and the anti and syn structures and the transition state (TS) structures connecting them have been examined. In each of these compounds, the anti structure was predicted to be more stable than the syn structure and the relative energy of the TS structure was considerably higher than those of the anti and syn structures. The energy difference between anti and syn of 1 is slightly smaller than those of 2 and 3 owing to the existence of hydrogen bonding between O in the nitroso group and H in the NH 2 group.