Process Research of 1-(3,4-dichloropheny)-3-methyl-pyrazolone-5-one Synthesis

摘要

The new process of 1-(3,4-dichloropheny)-3-methyl-pyrazolone-5-one (34DCPMP) synthesis had been discovered, which using 3,4-dichloro phenylhydrazine hydrochloride(DCPH) and ethyl acetoacetate as the raw material, The product was obtained by the route during cyclization in aqueous medium. The structure of products was confirmed by ~1HNMR, ~(13)CNMR and IR. The effects of factors on the yield of products were investigated. It was found that the yield of 34DCPMP can reach 98.7% under the optimal reaction condition of n(34DCPH):n(ethyl acetoacetate) with 1:1.1, n(34DCPH):n(Na_2SO_3) with 1.3:1 at 80°C, and pH 7.5 for 3h. The chromatographic purity can be higher than 98.2%.