反应详情

温度

60 °C

A mixture of 5-(2-bromoacetyl)pyrazole-3-carboxylic acid ethyl ester (6.2 g), thiourea (1.8 g), and ethanol (100 ml) was stirred at 60° C. for 30 minutes and concentrated. The residue was dissolved in 100 ml of 1N HCl solution, and washed with ethyl ether (2×100 ml). The aqueous solution was neutralized with NaHCO3. The resulting precipitates were collected through a filtration to afford 4.05 g of 5-(2-aminothiazol-4-yl)pyrazole-3-carboxylic acid ethyl ester as brown solids, mp 205°-207° C. NMR: 1.40 (t, 3H), 4.39 (q, 2H), 5.8 (bs, 2H), 6.85 (s, 1H), 7.03 (s, 1H).

1. concentrationconcentrated
2. dissolutionThe residue was dissolved in 100 ml of 1N HCl solution
3. washwashed with ethyl ether (2×100 ml)
4. customThe resulting precipitates
5. filtrationwere collected through a filtration