METHOD FOR PREPARING RACEMIC AND PURE ENANTIOMERS OF DERIVATIVES OF 1,5-DIARYL-3-TRIFLUOROMETHYL-2-PYRAZOLINES Russian patent published in 2006 - IPC C07D231/06 

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention proposes a method for synthesis of compounds of the general formula (1) that involves racemic mixtures of (±)-(1) and pure enantiomers of compound (-)-(1) and (+)-(1) wherein R₁ and R₃ are similar or different and represent hydrogen, chlorine, fluorine atom, methyl, trifluoromethyl or methoxy-group; R₂ represents hydrogen, chlorine, fluorine atom, methyl, trifluoromethyl, methoxy-, trifluoromethoxy-group, methylsulfonyl or aminosulfonyl group; R₄ represents hydrogen, chlorine, fluorine atom, methyl, trifluoromethyl, methoxy-, trifluoromethoxy-group, methylsulfonyl or aminosulfonyl group under condition that one of substitutes in R₂ or R₄ means methylsulfonyl or aminosulfonyl group. Method involves preparing a racemic mixture of compounds of the general formula (±)-(1) by interaction of (E)-1,1,1-trifluoro-4-aryl-3-butene-2-one with phenylhydrazine followed by treatment with chlorosulfoacid or by interaction with chlorosulfoacid and the following reaction with sodium hydroxide and, eventually, with thionyl chloride. The compound synthesized by any of these methods is subjected for interaction with ammonium carbonate or ammonia or with sodium sulfite and methyl iodide or methyl sulfonate. Also, for preparing pure enantiomers of compound of the general formula (1) in separating the racemic mixture of the general formula (±)-(1) the reaction is carried out with optically active ephedrine that results to formation of sodium salt of each enantiomer, the reaction with thionyl chloride and ammonium carbonate or ammonia or with sodium sulfite and methyl iodide or methyl sulfonate instead thionyl chloride to synthesize pure enantiomers of compound of the general formula (-)-(1) or (+)-(1) separately. Invention provides the development of commercially useful method for synthesis of compounds of the formula (1) based on using the cheaper and available parent reagents.

EFFECT: improved method of synthesis.

6 cl, 2 ex