反应详情

温度

50 °C

A mixture of 2-methyl-4-o-tolyl-thiazole-5-carboxylic acid ethyl ester (0.84 g, 3.20 mmol, 1.0 equiv) and potassium hydroxide (0.36 g, 6.40 mmol, 2.0 equiv) in 50% aqueous methanol (10 mL) was heated to 50° C. for 5 hours. The mixture was concentrated, and the residue diluted with water and acidified to about pH 1 by the addition of 6N HCl solution. The resultant solution was extracted with ethyl acetate (3×). The combined extracts were dried over magnesium sulphate, filtered, and concentrated under vacuum to afford 0.61 g (81%) of 2-methyl-4-o-tolyl-thiazole-5-carboxylic acid as a solid. LCMS (ESI) m+H=234.0; 1H NMR (400 MHz, CDCl3) δ: 7.32-7.17 (m, 4H), 2.75 (s, 3H), 2.17 (s, 3H).

1. concentrationThe mixture was concentrated
2. additionthe residue diluted with water
3. additionacidified to about pH 1 by the addition of 6N HCl solution
4. extractionThe resultant solution was extracted with ethyl acetate (3×)
5. dry with materialThe combined extracts were dried over magnesium sulphate
6. filtrationfiltered
7. concentrationconcentrated under vacuum