Clove (Eugenia Caryophyllata) Extraction and Synthesis of New Pyrazole Derivatives from Eugenol

An efficient method for the preparation of novel 1,3,4-trisubs tituted 4,5-dihydro-1H-pyrazole s via 1,3-dipolar cycloaddition has been described. Using this method, various pyrazole were synthesized from eugenol, a major phenolic constituent of clove bud essential oil, as dipolarophilic system and N-aryl-C-ethoxycarbonitrilimine: the (Z)-ethyl 2-bromo-2 - (2-(4-chlorophenyl)-hydrazono) acetate.