Ring transformation and reactions of 2-amino-4,5-dihydrofuran-3,4-dicarbonitriles

Abstract

The 2-amino-4,5-dihydrofuran-3,4-dicarbonitriles (1a–f) were thermally aromatized to the 2-aminofuran-3-carbonitriles (2a–f) which, in turn, underwent photoxidative ring transformation into the 2,5-dihydro-5-hydroxy-2-oxopyrrole-3-carbonitriles (3b–e). Mild acidic hydrolysis of the 2-amino-4,5-dihydrofuran-3,4-dicarbonitriles (1a–g) led to the tetrahydro-2-oxofuran-3,4-dicarbo-nitriles (4a–g). The representative compound (4a) was converted into the 2,5-dihydro-2-oxofuran-3-carbonitrile (5) or further transformed into the 3,3a-dihydrofuro[3,4-c]pyrrole-1,4,6-trione (6).