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 2,3-diaryl-6-nitrophenyl-cis-3,3a-dihydropyrazolo [3',4':4,5] thiazolo [3,2-b]-s-triazoles 3 has been achieved by the condensation of 3-p-nitrophenyl-s-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-p-nitrophenyl-6-arylidene thiazolo [3,2-b]-s-triazolo-5(6H)-one 2 followed by treatment with 2,4-dinitrophenylhydrazine. The structures 3 were supported by IR and H-1 NMR spectral data. The appearance of two doublets (J=8.2 Hz) at delta 8.35 and 8.86 corroborated the cyclic structure and cis configuration. The antibacterial and antifungal activities of the system have also been evaluated.