反应详情

A mixture of methyl 2-(isobutylamino)thiophene-3-carboxylate (2.1 g, 9.9 mmol), sodium hydroxide (0.39 g, 9.8 mmol), water (20 mL) and methanol (10 mL) was heated at reflux for 2 h and cooled to room temperature. Methanol was removed under reduced pressure; the residue was diluted with dichloromethane (10 mL) and cooled to 0° C. Triphosgene (5.85 g, 19.7 mmol) was added portionwise; the reaction mixture was stirred for 18 h and diluted with dichloromethane. The organic layer was separated, dried over anhydrous sodium sulfate and concentrated to provide the crude product as a light brown solid (2.0 g). This material was used in the next step (Step D) without any purification. 1H NMR (400 MHz, CDCl3): δ 7.25 (d, 1H), 6.95 (d, 1H), 3.79 (d, 2H), 2.40-2.36 (m, 1H), 1.02 (d, 6H).

1. temperaturewas heated
2. temperatureat reflux for 2 h
3. customMethanol was removed under reduced pressure
4. additionthe residue was diluted with dichloromethane (10 mL)
5. temperaturecooled to 0° C
6. customThe organic layer was separated
7. dry with materialdried over anhydrous sodium sulfate
8. concentrationconcentrated