N2-Methyl-5-(trifluoromethyl)pyridine-2,3-diamine → 5-{4-(3-Methyl-6-trifluoromethylimidazo[5,4-b]pyridin-2-ylmethoxy)benzyl}thiazolidine-2,4-dione

Participants

Reaction Steps

4.16 g of 5-(4-(2-oxoethoxy)benzyl)thiazolidine-2,4-dione (prepared as described in Preparation 47) were added to a solution of 3.00 g of 3-amino-2-methylamino-5-trifluoromethylpyridine in a mixture of 6 ml of ethanol and 6 ml of acetic acid, and the resulting mixture was stirred at room temperature for 4 hours. At the end of this time, the reaction mixture was freed from the solvent by distillation under reduced pressure. 50 ml of 1,2-dimethoxyethane and 5.2 g of iodine were added to the residue, and the resulting mixture was stirred at 60° C. for one day. At the end of this time, the reaction mixture was poured into water, after which it was extracted with ethyl acetate. The extract was washed with an aqueous solution of sodium chloride and dried over anhydrous sodium sulfate, after which the solvent-was removed by distillation under reduced pressure. The residue was purified by column chromatography through silica gel, using a 1:1 by volume mixture of hexane and ethyl acetate as the eluent. The product was crystallized by trituration with ethyl acetate, to give 520 mg of the title compound, melting at 212-214° C.

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