PROCESO PARA LA SINTESIS DE HIDRO-CLORURO DE PIOGLITAZONA

Sales de 4-[2-(5-etil-2-piridinil)-etoxi]-benzaldehído de fórmula (II), en la cual HX es HCl, CF3COOH, C4H4O4, (COOH)2 The invention relates to a process for the synthesis of pioglitazone hydrogen chloride - which is an antidiabetic drug - via novel intermediates by reacting 4-[2-(5-ethyl-2-pyridinyl)-ethoxy]-benzaldehyde salt of formula (II), wherein HX is: HCI, CF3COOH, C4H4O4, (COOH)2 with a base and then thiazolidine-2,4-dione, and the obtained 5-[[4-[2-(5-ethyl-2-pyridinyl)ethoxy]phenyl]methylene]-2,4-thiazolidinedione base is treated with hydrochloric acid and the obtained 5-[[4-[2-(5-ethyl-2-pyridinyl)ethoxy]phenyl] methylene]-2,4-tiazolidinedione hydrogen chloride of formula(III) is hydrogenated in the presence of a catalyst. Further objects of the invention are the salts of general formula (II) and the benzylidene derivative of formula (III).