Collect. Czech. Chem. Commun. 2004, 69, 1472-1478

Structure of Disilylated Acetoacetohydroxamic Acid

Jan Schramla,*, Jiří Hetflejša, Stanislav Šabataa, Vratislav Blechtaa, Jan Sýkoraa and Jana Roithováb

a Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, Rozvojová 135, 165 02 Prague 6, Czech Republic
b J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejškova 3, 182 23 Prague 8, Czech Republic


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.

Keywords: NMR spectroscopy; Hydroxamic acids; Ketenes; Hydroxylamines; Silyl migration; Silylation; Protecting groups.

References: 29 live references.