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Cyclization of amino acid hydrazide afforded a new class of heteroatom activated β-lactams. These compounds are potent parent nuclei which possess significant biological activity

The ir spectrum of imidazole derivatives, which have an alkoxycarbonyl group and a carboxamide group at the 4- and 5-positions of the imidazole ring respectively, exhibits the shift of the ester carbonyl band to a lower wave number. This phenomenon was investigated by spectroscopic measurements of a group of relevant compounds. The results indicate that the shift is caused by the intramolecular hydrogen bonds between the hydrogen atom of the amide and the carbonyl oxygen of the ester which is enhanced by the resonance stabilization of the imidazole ring.