反应详情

To a stirred solution of 3-Amino-5-phenyl-thiophene-2-carboxylic acid methyl ester (1.82 g, 7.8 mmol) in 1,2-dichloroethane (40 mL) was added sequentially 2-methoxypropene (3.0 mL, 31.2 mmol), AcOH (1.8 mL, 31.2 mmol) and NaBH(OAc)3 (3.31 g, 15.6 mmol) and stirred for 2 hrs. It was then diluted with EtOAc and H2O. The aqueous solution was adjusted to pH=7 by adding NaHCO3. The aqueous phase was extracted with EtOAc, the combined extract was washed with brine and dried on MgSO4 and filtered. Purification on bond elute with hexane to 5% EtOAc-hexane furnished 3-Isopropylamino-5-phenyl-thiophene-2-carboxylic acid methyl ester (2.07 g, 96% yield). 1H NMR (CDCl3, 400 MHz): δ 7.62 (d, 2H), 7.40 (m, 3H), 6.91 (s, 1H), 3.84 (s, 3H), 3.71 (m, 1H), 1.35 (d, 6H).

1. extractionThe aqueous phase was extracted with EtOAc
2. extractionthe combined extract
3. washwas washed with brine
4. customdried on MgSO4
5. filtrationfiltered
6. customPurification on bond
7. washelute with hexane to 5% EtOAc-hexane