Synthesis and Antimicrobial Activity of Novel Furothienoquinoxalines, Pyranothienoquinoxalines and Pyrimidopyranothienoquinoxalines

The reaction of ethyl‐3‐mercaptoquinoxaline‐2‐carboxylate with phenacyl bromide, ethyl chloroacetate, chloroacetonitrile or chloroacetone furnished the corresponding 3‐hydroxy thieno[2,3‐ b ]quinoxaline. 2‐Cyano‐3‐hydroxythieno[2,3‐ b ]quinoxaline and 2‐acetyl‐3‐hydroxythieno[2,3‐ b ]quinoxa line were employed as precursors in the synthesis of some novel furo[2′,3′:4,5]thieno[2,3‐ b ]quinoxaline, pyrano[2′,3′:4,5]thieno[2,3‐ b ]quinoxaline and other heterocyclic systems fused with thieno[2,3‐ b ]quinoxalines. The antibacterial and antifungal activities of some the synthesised compounds were studied.