LAUSR

The condensation reaction of benzyl carbazate with the ketones, viz., dimethylketone, dipropylketone, cyclobutanone, cyclopentanone, cyclohexanone, cycloheptanone, 2-acetylpyridine, 3-acetylpyridine and 4-acetylpyridine, yielded the Schiff bases [benzyl 2-(propan-2-ylidene)hydrazinecarboxylate (1), benzyl 2-(heptan-4-ylidene)hydrazinecarboxylate (2), benzyl 2-(cyclobutanylidene)hydrazinecarboxylate (3), benzyl 2-(cyclopentnylidene)hydrazinecarboxylate (4), benzyl 2-(cyclohexanylidene)hydrazinecarboxylate (5), benzyl 2-(cycloheptanylidene)hydrazinecarboxylate (6), benzyl 2-(1-(pyridine-2-yl) ethylidene)hydrazinecarboxylate (7), benzyl 2-(1-(pyridine-3-yl) ethylidene)hydrazinecarboxylate (8) and benzyl 2-(1-(pyridine-4-yl) ethylidene)hydrazinecarboxylate (9)], respectively. These were all characterized by elemental analysis, FT-IR and NMR (1H and 13C) spectroscopic methods, and in addition, the structures of compounds 4, 8 and 9 have been confirmed by single-crystal X-ray diffraction studies, and their crystal structures are shown to be stabilized by hydrogen bonding. The thermal properties of all the Schiff bases have been studied in air and all of them underwent melting followed by endo- and exothermic decomposition processes to yield an ethanimine (CH3–CH=NH) intermediate which in turn decomposes exothermically to give gaseous products. In a nitrogen atmosphere, these compounds also show similar thermal behavior but with the absence of an intermediate. A docking study of compounds 2, 4 and 9 with human BChE provides useful structural information on their inhibition properties.