反应详情

A mixture of 2-thienylacetic acid methyl ester, 1.41 g. (0.01 mol) and acetic anhydride, 4.2 g. (0.04 mol) was heated at 70°-80° C. and 0.2 g. of 85% H3PO4 was added dropwise with mechanically stirring. The reaction was somewhat exothermic but cooling was not necessary. The mixture was maintained between 70°-80° C. for 3 hours, and then, poured onto ice-water followed by extraction with ether. Organic layer was washed with water several times, dried over anhyd. MgSO4 and evaporated. The residue was distilled at 2mmHg and a fraction between 160° C. and 172° C. was collected. This material was gradually crystallized and could be recrystallized from the mixture of light-petroleum and benzene. m.p. 43°-44° C. Yield; 1.39 g. (76.5%)

1. temperature(0.04 mol) was heated at 70°-80° C.
2. temperaturecooling
3. temperatureThe mixture was maintained between 70°-80° C. for 3 hours
4. additionpoured onto ice-water
5. extractionfollowed by extraction with ether
6. washOrganic layer was washed with water several times
7. customdried over anhyd
8. customMgSO4 and evaporated
9. distillationThe residue was distilled at 2mmHg
10. customa fraction between 160° C. and 172° C. was collected
11. customThis material was gradually crystallized
12. customcould be recrystallized from the mixture of light-petroleum and benzene