Structure of Disilylated Acetoacetohydroxamic Acid

Abstract

As proved by 29Si and 15N NMR spectra, the reaction of N,O-bis(trimethylsilyl)hydroxylamine with diketene yields a mixture of E and Z isomers of O,O'-bis(trimethylsilyl)acetoacetohydroximic acid ((E)-3 and (Z)-3), and not the conformers of N,O-bis(trimethylsilyl)acetoacetohydroxamic acid (1), as believed up to now. In contrast, the acetylation of N,O-dimethylhydroxylamine leads to methyl N-methylacetohydroxamate (5), analogous to the structure 1.