Solvent-free one-pot cyclization and acetylation of chalcones: Synthesis of some 1-acetyl pyrazoles and spectral correlations of 1-(3-(3,4-dimethylphenyl)-5-(substituted phenyl)-4,5-dihydro-1H-pyrazole-1-yl) ethanones

One-pot synthesis of some 1n-acetyl pyrazoles including 1-(3-(3,4-dimethylphenyl)-5-(substituted phenyl)-4,5-dihydro-1h-pyrazole-1-yl) ethanones has been achieved via solvent-free microwave irradiation using substituted chalcones,hydrazine hydrate and acetic anhydride in the presence of catalytic amount of fly-ash: pts catalyst. the yield of these 1n-acetyl pyrazole derivatives is more than 75%. the synthesized 1n-acetyl pyrazoline derivatives were characterized by their physical constants and spectral data. the infrared spectral νc[dbnd]n and c[dbnd]o (cm−1) frequencies,nmr chemical shifts (δ,ppm) of ha,hb,hc,ch3 protons,c[dbnd]n,c[dbnd]o and ch3 carbons of 1-(3-(3,4-dimethylphenyl)-5-(substituted phenyl)-4,5-dihydro-1h-pyrazole-1-yl) ethanones have been assigned and correlated with hammett substituent constants and swain-lupton's parameters using single and multi-regression analysis. from the results of statistical analyses,the effect of substituents on the above group frequencies and chemical shifts of the acetylated pyrazoles were discussed. © 2013 king saud university