STEREOCHEMICAL INVESTIGATION IN THE 1,3-DIPOLAR CYCLOADDITIONS OF 3-NITRO-2-PHENYL-2H-1-BENZOPYRANS TO DIAZOALKANES - SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF NOVEL BENZOPYRANOPYRAZOLE DERIVATIVES

A series of 3-nitro-2-phenyl-2H-1-benzopyrans (3a-h) were prepared and treated with diazomethane and diazoethane to give various benzopyrano pyrazole derivatives namely ro-4-phenyl1benzopyrano3,4-cpyrazoline s(4a-h), 4-phenyl1benzopyrano 3,4-cpyrazoles (5a-h) and itro-4-phe ny1benzopyrano3,4-cpyrazolines(6a-h) respectively. The regio and s tereochemical outcome of these cycloadditions are discussed. The benzo pyranopyrazole derivatives 4a-h and 6a-h were tested for their antimic robial activities against S. aureus, S. lutea, B. subtilis, E. coil, S . typhosa, S. cerevesciae and C. albicans. Compounds 4a-h were found t o be moderately active against the gram positive bacteria and the fung i that were tested.