Synthesis of 4-(Phenylamino)quinazoline-2(1H)-selones and Diselenides from Isoselenocyanates: Dimroth Rearrangement of an Intermediate

Abstract

The reaction of anthranilonitriles 8 with phenyl isoselenocyanates (1a) in dry pyridine under reflux gave 4-(phenylamino)quinazoline-2(1H)-selones 9 (Scheme 2). They are easily oxidized and converted to diselenides of type 11. The analogous reaction of 8a with phenyl isothiocyanate (1b) yielded the quinazoline-2(1H)-thione 10 (Scheme 2). A reaction mechanism via a Dimroth rearrangement of the primarily formed intermediate is presented in Scheme 3. The molecular structures of 10 and 11a have been established by X-ray crystallography. Unexpectedly, no selone or diselenide was obtained in the case of the reaction with 3-aminobenzo[b]furan-2-carbonitrile (14). The only product isolated was the selenide 16 (Scheme 4), the structure of which has been established by X-ray crystallography.