Microwave enhanced solid support synthesis of fluorine containing benzopyrano-triazolo-thiadiazepines as potent anti-fungal agents

A facile, dry media procedure has been developed for the synthesis of a series of a new class of fluorine containing 3-alkyl-7-chloro-11a,12-dihydro-11-phenyl-12-(substituted aryl)-11H-benzopyrano[4,3-e][1,2,4]-triazolo[3,4-b][1,3,4]-thiadiazepines (4a–k) under microwaves using basic alumina as solid support. The reaction time has been brought down from hours (60–65 h) to minutes (3–5 min) with improved yield as compared to conventional method, demonstrating the versatility of the process. The method reported herein is devoid of the hazards of solution-phase reactions. The synthesized compounds have been screened ‘in vitro’ for anti-fungal activity against Rhizoctonia solani, Fusarium oxysporum and Collectotrichum capsici. Most of the compounds have shown good activity against these pathogens.

An efficient and environmentally benign synthesis of benzopyrano[4,3-e][1,2,4]-triazolo[3,4-b][1,3,4]-thiadiazepines is described from 4-amino-5-alkyl-3-mercaptotriazole and substituted 3-arylidene flavonones under microwave irradiation using basic alumina as solid support.Figure optionsDownload as PowerPoint slide