Synthesis of newer naphthylpyrazolines, pyrazoles and chalcone epoxides of expected biological activity

ABSTRACT

N-unsubstituted pyrazolines [IIa-d] were synthesized from the reaction of the chalcones [I] with hydrazine hydrate. The reaction of 2- naphthyl chalcones and hydrazine hydrate in boiling acetic acid gave 1-acetyl-5-aryl-3-[2'-naphthyl]-delta 2-pyrazolines [IIe-h]. Phenyl-, p-tolyl-and p-chlorophenyl-hydrazine reacted with 2-naphthyl chalcones [Ib, d] to give the corresponding 1, 5-diaryl-3-[2'naphthyl]-delta 2- pyrazolines [IIi-o], respectively. Treatment of the 2-naphthyl chalcones [Ia, c, d] with an ethereal diazomethane solution afforded 3-[2'naphthoyl]-4-aryl-delta2-pyrazolines [IIIa-c]. Dehydrogenation of the pyrazolines [IIi-o] to the corresponding 1, 5-diaryl-3-[2'- naphthyl]-pyrazoles [VIa-g] was carried out using tetrachloro- benzoquinone in dry ether. When the 2-naphthylchalcones [Ia-d] in dioxane were allowed to react with hydrogen peroxide in presence of sodium hydroxide, the epoxides [VIIa-d], respectively, were obtained. These compounds are known to have expected pesticidal activity