Synthesis and antifungal activity of novel pyrano[2′,3′:4,5]thiazolo[2,3-b]quinazolines, pyrido[2′,3′:4,5]thiazolo[2,3-b]quinazolines and pyrazolo[2′,3′:4,5]thiazolo[2,3-b]quinazolines

The starting materials thiazolo[2,3-b]quinazolines (5a,b) were obtained in one pot synthesis by treating octahydroquinazoline (2) with chloroacetic acid and aromatic aldehydes. Thiazoloquinazoline (5) was reacted with CH2(CN)(2)/piperidine and CH2(CN)(2)/NaOH (CH3OH), to furnish pyrano[2', 3':4,5]thiazolo[2,3-b]quinazolines (6a,b) and pyrido[2',3':4,5]thiazolo[2, 3-b]quinazoline (7), respectively. Refluxing of 5a with NH2CSNH2/KOH and hydrazines in ethanol furnished the corresponding, [1,3]thiazino-[4'5':4,5]thiazolo[2,3-b]quinazoline (10) and pyrazolo[3',4':4,5]thiazolo[2, 3-b]quinazolines (11a,b), respectively. Antifungal activity was shown for some of the synthesized compounds. (C) 2000 Published by Elsevier Science S.A. All rights reserved.