The crystal and molecular structures of methyl (N-benzoylaminooxy)acet
ate (MBAOA) have been determined by X-ray diffraction at room temperat
ure. In the crystal the amide C=O of one molecule is hydrogen-bonded t
o the amide NH of an adjacent molecule (O1 ... N1' = 2.850(2) Angstrom
, O1 ... H6'-N1' = 158(2)degrees). The ester C=O bond is cis oriented
to the C-O (aminooxy) bond (the O2-C8-C0-O4 torsion angle is 2.6(3)deg
rees). IR and Raman spectra of MBAOA and its deuterated analogs have b
een measured in the solid state and in solution. In polar solvents the
ester nu C=O was observed as a doublet feature in IR spectra, suggest
ing the existence of the two conformers having different torsion angle
s around the (O-)C-C(=O) bond. By combining the X-ray crystallographic
result with the IR and Raman data, it is suggested that the conformer
with the higher frequency of the ester nu C=O in solution has the est
er C=O bond cis oriented to the C-O (aminooxy) bond.