反应详情

A mixture of 25.5 g (80 mmol) of 1,4-dibromo-2,2-diethoxy-3-butanone, 11.8 g (100 mmol) of N-amidinothiourea, and 150 ml of tetrahydrofuran was heated at reflux for 3 hours. The mixture was filtered to remove some insoluble solid, and the filtrate was concentrated. The residue was triturated with 200 ml of saturated sodium bicarbonate, then extracted four times with a total of 500 ml of ethyl acetate. The combined ethyl acetate extracts were dried over sodium sulfate, filtered and evaporated leaving a solid. Recrystallization from 250 ml of acetonitrile, after decolorization with charcoal, afforded 9.7 g (36%) of 2-guanidino-4-(2-bromo-1,1-diethoxyethyl)thiazole as a white solid, mp 157°-158°; calcd. for C10H17N4O2SBr: C, 35.62; H, 5.08; N, 16.61; Br, 23.69; S, 9.51; found: C, 35.60; H, 4.97; N, 16.99; Br, 23.75; S, 9.59.

1. temperaturewas heated
2. temperatureat reflux for 3 hours
3. filtrationThe mixture was filtered
4. customto remove some insoluble solid
5. concentrationthe filtrate was concentrated
6. customThe residue was triturated with 200 ml of saturated sodium bicarbonate
7. extractionextracted four times with a total of 500 ml of ethyl acetate
8. dry with materialThe combined ethyl acetate extracts were dried over sodium sulfate
9. filtrationfiltered
10. customevaporated
11. customleaving a solid
12. customRecrystallization from 250 ml of acetonitrile