PURPOSE: To prepare the titled compound useful as a stabilizer of organic materials, herbicide, etc., economically in an industrial scale, by condensing a pyrazolone compound with a benzene compound and carbon tetrachloride in the presence of an aluminum halide, and hydrolyzing the reaction product.
CONSTITUTION: The pyrazolone compound of formulaI(R' is H or lower alkyl; R2 is lower alkyl) is condensed with the benzene compound of formula II (X is halogen; n is 1, 2 or 3) and carbon tetrachloride in the presence of an aluminum halide such as anhydrous aluminum chloride, anhydrous aluminum bromide, etc., and the condensation product is hydrolyzed to obtain the objective 4-benzoyl-5-hydroxypyrazole compound of formula III. The process enables the production of the objective compound from inexpensive and easily handleable benzene compound and carbon tetrachloride in an yield of as high as e.g. ≥90%.
NISHIKAWA TETSUJI
NAKAJIMA TOSHIO
MINAMIDA KOUJI
MAEDA MASARU
