Abstract:
<p align="justify"> We confirmed, on the basis of chemical and physicochemical (melting points, IR- and 1H-NMR-spectra) data, that the products isolated by monoacylation of cyclic maleic- and phthalic-hydrazides have only the O-acyl derivatives nature although owing to tautomerism. These hydrazides may give rise to N- or/and O-acyl derivatives in such reactions. Simultaneously, we showed that the claims for the obtainment of N-acyl derivatives of cyclic maleic- and phthalic-hydrazides were not valid. Also by reacting the cyclic maleic-, respectively phthalic-hydrazide, with 4-chlorobenzoylchloride two new O-monoacylderivatives [3-( 4-chlorobenzoyloxy)-l-H-pyridazin-6-one and 1-(4-chlorobenzoyloxy)-3-H-phthalazin-l-one] were obtained </p>