Sodium → 5-(alpha-Carboxy-m-trifluoromethylbenzylmercapto)-pyridine-2-carboxylic acid

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Reaction Steps

To the solution prepared from 80 ml of methanol and 0.89 g of sodium, 6.53 g of 5-mercaptopyridine-2-carboxylic acid methyl ester are added, followed by the solution of 12.6 g of methyl α-bromo-m-trifluoromethylphenylacetate in 50 ml of methanol while stirring under nitrogen. The mixture is warmed for 1/2 hour on the steam bath and allowed to stand at room temperature overnight. It is evaporated, the residue taken up in water-diethyl ether, the organic phase washed with water, dried and evaporated. The residue is dissolved in the minimum amount of methanol-isopropanol (1:1), the solution mixed with 85 ml of N aqueous sodium hydroxide, warmed for 1/2 hour on the steam bath, and stored at room temperature overnight. The mixture is evaporated, the residue taken up in 2 N hydrochloric acid and the mixture extracted with diethyl ether-ethyl acetate (1:1). The extract is washed with water, dried and evaporated and the residue recrystalized from diethyl ether-ethyl acetate, to yield the 5-(α-carboxy-m-trifluoromethylbenzylmercapto)-pyridine-2-carboxylic acid melting at 190°-195°.

Provenance & Evidence