Condensed bridgehead nitrogen heterocyclic systems:: Synthesis, bioactivity and stereochemistry of pyrazolo [3′,4′:4,5] thiazolo [3,2-b]-s-triazoles

A facile synthesis of 3-aryl-6-o-chlorophenyl-trans-3,3a-dihydropyrazolo [3',4' 4,5] thiazolo [3,2-b]-s-triazoles 3 has been achieved by the condensation of 3-o-chlorophenyls-triazole-5-thione 1 with chloroacetic acid and aldehydes in the presence of acetic anhydride, anhyd sodium acetate and gl acetic acid to yield 2-o-chlorophenyl-6-arylidene thiazolo [3,2-b]-s-triazoIo-5-(6H)-ones 2 followed by treatment with hydrazine hydrate. The structures 3 were supported by IR and H-1 NMR spectral data. The appearance of two doublets (J = 4.5 Hz) at delta 7.90 and 7.96 corroborates the cyclic structure and trans configuration. The antibacterial and antifungal activities of the system have also been evaluated.