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 thieno2,3‐b]quinoxaline. 2‐Cyano‐3‐hydroxythieno2,3‐b]quinoxaline and 2‐acetyl‐3‐hydroxythieno2,3‐b]quinoxa line were employed as precursors in the synthesis of some novel furo2′,3′:4,5]thieno2,3‐b]quinoxaline, pyrano2′,3′:4,5]thieno2,3‐b]quinoxaline and other heterocyclic systems fused with thieno2,3‐b]quinoxalines. The antibacterial and antifungal activities of some the synthesised compounds were studied.