Microwave-assisted three-component synthesis of some novel 1-alkyl-1H-indole-2,3-dione 3-(o-alkyloxime) derivatives as potential chemotherapeutic agents

摘要

A convenient and efficient method for a one-pot conversion of N-alkylisatins to N-alkylisatin O-alkyloximes 7a-7n as potential chemotherapeutic agents is described (Scheme) (isatin=1H-indole-2,3-dione). In this method, the microwave-assisted three-component reaction of N-alkylisatins 8, hydroxylamine hydrochloride, and diverse alkyl halides in the presence of K_2CO_3 and Bu_4NBr furnishes the corresponding N-alkylisatin O-alkyloximes under solvent-free condition in short times (2-10 min) and good to excellent yields (62-83%). The O-alkylation of in situ generated isatin oximes with alkyl halides was achieved regioselectively, and (Z)-O-alkyloximes were produced dominantly. PM3 Semi-empirical quantum-mechanic calculations were performed to rationalize the evidences, and the calculations indicated a lower heat of formation for the (Z)-O-alkyloximes.