METHOD FOR PREPARING PIOGLITAZONE AS ANTIDIABETIC AGENT Russian patent published in 2006 - IPC C07D417/12 C07D213/30 A61K31/427 A61P3/10 

FIELD: organic chemistry, chemical technology, medicine, endocrinology.

SUBSTANCE: invention relates to a method for preparing an antidiabetic agent pioglitazone of the formula (I): . Method involves condensation of 4-substituted phenol or phenolate of the general formula (II): wherein R represents organic radical comprising amino-group and chosen from group comprising group of the general formula: -NHR^a (IIa) wherein R^a means hydrogen atom or protective group that is removed before the following treatment, and group of the general formula: wherein R^b represents carboxyl group as free acid or as salt or ester; M represents hydrogen atom or alkaline metal with pyridine base of the general formula (III): wherein Z means a removing group distinguishing from halogen atom and wherein the following steps are carried out: (a) diazotization reaction of amino-group as a moiety of organic radical R; (b) conversion of diazotized radical R to derivative of 2-halogenpropionate or 2-halogenpropionitrile of the formula: wherein R^b is determined above; X represents halogen atom; (c) cyclization of derivative of 2-halogenpropionate or 2-halogenpropionitrile with thiourea, and (d) hydrolysis of imine prepared. In case when R represents group of the formula (IIa) method involves firstly carrying out the condensation reaction followed by carrying out steps (a)-(d) to obtain agent of the formula (I); or in case when R represents group of the formula (IIb) then method involves firstly carrying out steps (a)-(d) followed by condensation with pyridine base of the general formula (III) to obtain agent of the formula (I). Also, invention describes compounds of the formula (V): wherein R^a represents a protective group chosen from group comprising acyl, n-alkoxycarbonyl, tert.-butoxycarbonyl, benzyloxycarbonyl, 9-fluorenylmethoxycarbonyl, allyloxycarbonyl, 2-cyanoethoxycarbonyl as an intermediate substance in synthesis of compound of the formula (I).

EFFECT: improved preparing method of agent.

12 cl, 5 ex