The X-ray structure of N-(Acetylamino)phthalimide, an atypical triacylhydrazine

N-(Acetylamino)phthalimide [monoclinic, a = 7.0228(15), b = 4.7285(8), c = 28.882(6) Å, β = 90.131(7)° , space group P21/c] shows an unusual crystal structure with marked pyramidalization at the phthalimide N and strong intermolecular NH to CO hydrogen bonding leading to the groups at the two ends of the hydrazine adopting an almost perpendicular arrangement. A survey of previous triacyl and tetraacyl hydrazine structures shows that both these features are unusual, with most examples being essentially planar at N and with torsion angles about the N–N bond of 63–82°.