Water → 2-Methyl-4-(6-carbomethoxyhexyl)-thiazole-5-carboxylic acid

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Reaction Steps

5.15 g of 2-methyl-4-(6-carboxyhexyl)-thiazole-5-carboxylic acid (IX, R1 = CH3) and 5.4 g of p-toluenesulphonic acid monohydrate were dissolved in 200 ml of methanol. The reaction mixture was stirred for 2 hours at room temperature, then poured onto 500 ml of water. After saturating the aqueous solution with ammonium sulphate it was extracted with 3 × 200 ml of ethyl acetate, the ethyl acetate extract was washed with water, dried over sodium sulphate and evaporated in vacuo. Recrystallization of the obtained crude product from a mixture of diethyl ether and n-hexane afforded 4.3 g of 2-methyl-4-(6-carbomethoxyhexyl)-thiazole-5-carboxylic acid (X, R1 = CH3). M.p.: 106°-107° C. IR spectrum (KBr): ν OH (carboxylic acid) 3200-2200, ν C=O 1735, 1695, ν C-O 1235 cm-1.

Provenance & Evidence