synthesis and properties of 1,3-dihydrothieno[3,4-b]quinoxalline derivatives

Abstract

1,3-dihydrothieno[3,4-b]quinoxaline derivatives(2) are relatively stable and there are various applications. Thieno[3,4-b]quinoxaline were obtained from 2 by oxidation and simple base-catalyzed Pummerer dehydration. Aromatic aldehydes can react with 2 to 3 by a Knoeveagel condensation. The two α-positions to the S-atom are acidic, hence the condensation can occurs both position when excess aldehydes added in a small amount of diethyl ether of basic condition. The unsaturated aromatic functional groups are attached with the position to the Z,Z-configuration.