反应详情

温度

60 °C

A mixture of 5-(2-bromoacetyl)pyrazole-3-carboxylic acid ethyl ester (5.30 g), thioacetamide (1.60 g), and ethanol (100 ml) was stirred at 60° C. for 30 minutes and concentrated. The residue was dissolved in 50 ml of 2N HCl solution, and washed with ethyl ether (2×50 ml). The aqueous solution was separated and neutralized with solid NaHCO3. The mixture was then extracted with ethyl acetate (233 100 ml). The ethyl acetate solution was dried over sodium sulfate and concentrated to afford 3.46 g of 5-(2-methylthiazol-4-yl)pyrazole-3-carboxylic acid ethyl ester as pale yellow solids, mp 141-142° C. NMR: 1.41 (t, 3H), 2.78 (s, 3H, thiazolyl methyl), 4.42 (q, 2H), 7.15 (s, 1H, thiazolyl H), 7.47 (s, 1H, 4-pyrazolyl H).

1. concentrationconcentrated
2. dissolutionThe residue was dissolved in 50 ml of 2N HCl solution
3. washwashed with ethyl ether (2×50 ml)
4. customThe aqueous solution was separated
5. extractionThe mixture was then extracted with ethyl acetate (233 100 ml)
6. dry with materialThe ethyl acetate solution was dried over sodium sulfate
7. concentrationconcentrated