Synthesis, structural and theoretical studies of new ring-chain adducts of 5(4H)-oxazol-5-ones and aldehyde methylhydrazones

A series of novel derivatives 3a–g were efficiently synthesized by ring opening of 5(4H)-oxazol-5-ones with aromatic aldehyde methylhydrazones. Ab initio and DFT calculations were carried out on compound 3a and its model FMPH and compared with the data obtained by X-ray crystal-structure analysis. In order to correlate structural features to biological properties, the conformational characteristic and rotational barrier of open-chain derivatives 3a were studied. q 2004 Published by Elsevier B.V.