反应详情

A solution of 5,6-dihydro-5,5-dimethylthieno[3,2-b]pyran-7-one (1.0 g, 5,5 mmol), pyrrolidine (2.3ml, 27.4(mmol) sodium cyanoborohydride (0.345 g, 5.5 mmol) and 1N aqueous hydrochloric acid (5.5ml, 5.5 mmol) in methanol (15ml) was stirred at rt for 1 day. Additional sodium cyanoborohydride (0.345 g, 5.5 mmol) was added and the solution was stirred an additional 1 day; additional sodium cyanoborohydride (1.0 g, 15.9 mmol) was added again and the mixture stirred 5 additional days. The mixture was poured into water (100 ml) and extracted with dichloromethane. The dichloromethane solution was washed with water and dried over sodium sulfate. The solvent was evaporated in vacuo and the residue was purified by medium pressure chromatography using 2% methanol in dichloromethane as the eluant to give the product 0.70 g (54%) as a yellow solid; mp 49°-50° C.; IR(KBr): 2971, 1560 and 1394 cm-1 ; MS:m/z 238 (MH+); 1H NMR (CDCl3): δ 1.27(s,3H), 1.45(s3H), 1.80(m,4H), 1.91(m,2H), 2.76(m,4H), 4.09(m,1H), 6.57(d,J=5.4 Hz,1H), and 7.04(d,J=5.4 Hz,1H).

1. stirringthe mixture stirred 5 additional days
2. extractionextracted with dichloromethane
3. washThe dichloromethane solution was washed with water
4. dry with materialdried over sodium sulfate
5. customThe solvent was evaporated in vacuo
6. customthe residue was purified by medium pressure chromatography