反应详情

Thiourea (20.9 g., 0.275 mole) was dissolved in 250 ml. of refluxing ethanol. 2-Bromo-3-pentanone (41.3 g., 0.25 mole), dissolved in 50 ml. of ethanol, was added dropwise over 25 minutes to the refluxing thiourea solution. Following an additional 2 hours of reflux, the reaction was boiled down to approximately 100 ml., cooled and the crude product recovered as the hydrobromide salt by filtration. Purified 2-amino-4-ethyl-5-methylthiazole (15.1 g.; m.p. 45°-50° C.; m/e calcd: 142; found: 142) was obtained by dissolution in water and reprecipitation with aqueous 3 N potassium hydroxide.

1. temperatureof reflux
2. temperature, cooled
3. filtrationthe crude product recovered as the hydrobromide salt by filtration