STUDIES ON THE SYNTHESIS AND BIOACTIVITIE S OF SUBSTITUTED DIHYDROPYRAZOLE DERIVATIVES

A novel and convenient synthetic method for 1-phenyl-3-substituted phe nyl-4-triazolyldihy-dropyrazoles (1a-1b) and 3-substituted phenyl-4-tr iazolyldihydropyrazole (7) from alpha-triazolyl-beta-alkoxyacetophenon e 4 was described, The reaction condition was studied and optimized. 1 ,3,4,5-Multi-substituted dihydropyrazole 1c-1h were prepared through t he general cyclization of alpha,beta-unsaturated ketone with phenylhyd razine and their structures were confirmed by H-1 NMR, MS and elementa l analysis. Furthermore, 3,5-substituted dihydropyrazole 6(or 7) react ed with methyl(or ethyl) chloroformate and potassium thiocyanate to af ford 1,3,5-(or 4-)substituted dihydropyrazole 2a-2l. The results of pr eliminary bioassay presented that almost all compounds showed fungicid al, herbicidal and plant growth regulatory activities.