Intramolecular cyclization of O-(3,5-dinitrophenyl) and O-(3-amino-5-nitrophenyl) ketoximes, products of transformations of 1,3,5-trinitrobenzene. the synthesis of nitrobenzo[b]furans and 4-hydroxynitroindoles

Abstract

O-(3,5-Dinitrophenyl) ketoximes obtained in the reactions of ketoximes with 1,3,5-trinitrobenzene undergo acid-catalyzed cyclization into 2-substituted or 2,3-disubstituted 4,6-dinitrobenzo[b]furans. In analogous cyclization, products of selective reduction of a nitro group in O-(3,5-dinitrophenyl) ketoximes unexpectedly yield, along with 6-amino-4-nitrobenzofurans, 4-hydroxy-6- nitroindoles. The 4-NO2 group is displaced from 4,6-dinitrobenzo[b] furans in reactions with thiols in the presence of K2CO3. Conditions for nitration and sulfochlorination of 4,6-dinitrobenzo[b]furans in position 3 were found. Condensation of a 2-methyl derivative with dimethylformamide acetal was accomplished. © 2007 Springer Science+Business Media, Inc.