Abstract:

A new potassium compound of 4-iodo-3,5-dimethyl-pyrazole was synthesized with acetylacetone and hydrazine hydrate as the starting materials via oximation, condensation cyclization, reduction, diazotization and iodination. The compound was characterized by elemental analysis, IR, and 1H NMR. The reaction mechanism of oximation was studied with the program of Gaussian 03, at the MP2/6-311++ G(d,p) level. The stable geometric configurations of acetylacetone-3-oxime(1) and its intermediate of 4-hydroxy-3-nitrosopent-3-en-2-one(1b) were confirmed at the same calculation level. Furthermore, the crystal structure was determined by single-crystal X-ray diffraction analysis. The crystal is monoclinic, P21/c space group， with crystal parameters a=0.77645(10) nm,b=2.0361(2) nm,c=1.05761(13) nm, β=107.806(2)°, V=1591.9(3) m3,Z=4,Dc=2.012 g/cm3，F(000)=904, R1=0.0398.

Key words: acetylacetone, complex, reaction mechanism, quantum chemistry, 4-iodo-3,5-dimethyl-pyrazole