N,O-diacylhydroxylamines-structures in crystals and solutions.
The structures of four N,O-diacylhydroxylamines (RCOHNOCOR', R, R'= Me, Ph) were determined in the solid state by X-ray diffraction and studied by NMR and IR spectroscopies in solution. The interpretation of the results was supported by ab-initio calculations of various tautomers and conformers, rotational barriers and chemical shifts. The results indicate the absence of OH tautomers (R-C(OH)=N-O-C(O)-R', N-acyloxyimidic acid); the NH tautomers (R-C(O)-NH-O-C(O)-R', O-acylhydroxamic acid) are present in DMSO solutions as equilibrium mixtures of a few conformers, their exchange being the likely source of 15N and 13C NMR line broadening.
Institute of Chemical Process Fundamentals, Academy of Science of the Czech Republic, Rozvojova 135, 165 02, Prague 6, Czech Republic. schraml@icpf.cas.cz
Jan
J
Schraml
Jan
J
Sýkora
Pavel
P
Fiedler
Jana
J
Roithová
Jaromír
J
Mindl
Vratislav
V
Blechta
Ivana
I
Císarová
Otto
O
Exner