反应详情

To a solution of tert-butyl 6,7-dihydrothieno[3,2-c]pyridine-5(4H)-carboxylate (200 mg, 0.836 mmol) in TFA (6.89 ml, 89 mmol) was added concentrated nitric acid (0.053 ml, 0.836 mmol) dropwise at 0° C. The mixture was next concentrated then dissolved in 20 mL of ethyl acetate and di-tert-butyl dicarbonate (0.194 ml, 0.836 mmol) was added. The mixture was stirred at ambient for 60 minutes then the mixture was poured into a separatory funnel and washed with 20 mL of saturated aqueous sodium bicarbonate and 20 mL of saturated aqueous brine, dried over magnesium sulfate, filtered and concentrated. Purification by silica gel flash chromatography (Isco®, Redi-Sep® column, 2-50% ethyl acetate/hexane, linear gradient) afforded tert-butyl 2-nitro-6,7-dihydrothieno[3,2-c]pyridine-5(4H)-carboxylate (107 mg, 0.376 mmol). To this intermediate was added palladium on carbon (10% wt) (89 mg, 0.836 mmol) and the flask was capped with septa. The flask was evacuated and backfilled with nitrogen and 10 mL of methanol were added. The mixture was evacuated and backfilled with nitrogen 3 times then evacuated and backfilled with hydrogen. The mixture was stirred under hydrogen (1 atm, balloon) for 3 hours. The mixture was filtered through a celite pad and the filter cake washed with 20 mL of dichloromethane. The mixture was concentrated and the crude material was purified on silica gel flash chromatography (Isco®, Redi-Sep® column, 0-100% ethyl acetate/hexane, linear gradient) to obtain the title compound. MS (ESI) m/z 255.1 (M+H)+.

1. concentrationThe mixture was next concentrated
2. dissolutionthen dissolved in 20 mL of ethyl acetate
3. additionthe mixture was poured into a separatory funnel
4. washwashed with 20 mL of saturated aqueous sodium bicarbonate and 20 mL of saturated aqueous brine
5. dry with materialdried over magnesium sulfate
6. filtrationfiltered
7. concentrationconcentrated
8. customPurification by silica gel flash chromatography (Isco®, Redi-Sep® column, 2-50% ethyl acetate/hexane, linear gradient)