反应详情

Methanolic sodium methoxide (4.9M, 22.4 mL, 0.11 mol) was added via syringe to a solution of methyl 2-[(dimethylamino)carbonylthio]-4-ethoxybenzoate (crude, ca. 28.3 g, 0.10 mol) in methanol (100 mL) under nitrogen. The reaction mixture was heated at reflux for 30 minutes, then cooled with the aid of a water bath. Rotary evaporation yielded a solid. This was partitioned between dichloromethane (100 mL) and water (100 mL). The aqueous layer was washed with dichloromethane (3×40 mL), acidified to pH <1 with concentrated hydrochloric acid, and then extracted with dichloromethane (3×40 mL). These dichloromethane extracts were combined, dried (Na2SO4), and filtered. Rotary evaporation yielded methyl 4-ethoxy-2-mercaptobenzoate as an oil (18.4 g) that on standing formed a crystalline solid melting at 42°-44° C. PMR (CDCl3, 200 MHz): δ7.97 (d, 1H, H ortho to CO2CH3); 6.78 (d, 1H, H ortho to SH); 6.64 (dd, 1H, H para to SH); 5.06 (s, 1H, SH); 4.05 (q, 2H, OCH2CH3); 3.88 (s, 3H, CO2CH3); 1.42 (t, 3H, OCH2CH3). IR (Nujol): 1686 (vs, C=O) cm-1.

1. temperatureThe reaction mixture was heated
2. temperatureat reflux for 30 minutes
3. temperaturecooled with the aid of a water bath
4. customRotary evaporation
5. customyielded a solid
6. customThis was partitioned between dichloromethane (100 mL) and water (100 mL)
7. washThe aqueous layer was washed with dichloromethane (3×40 mL)
8. extractionextracted with dichloromethane (3×40 mL)
9. dry with materialdried (Na2SO4)
10. filtrationfiltered
11. customRotary evaporation