反应详情

Add sodium triacetoxyborohydride (1.70 g, 8.02 mmol) to a stirred solution of 4-amino-piperidine-1-carboxylic acid tert-butyl ester (1.0124 g, 5.06 mmol), 2,4-dichloro-thiazole-5-carbaldehyde (1.0113 g, 5.56 mmol), glacial acetic acid (0.31 mL, 5.42 mmol), and 1,2-dichloroethane (40 mL). Stir for 18 hours under nitrogen at room temperature. Pour the reaction into 2N NaOH (100 mL) and extract with ethyl acetate (3×100 mL). Dry the ethyl acetate over sodium sulfate and then filter off the sodium sulfate. Concentrate on a rotary evaporator and purify the crude product by flash chromatography on silica gel eluting with 35% ethyl acetate/hexanes then with 100% ethyl acetate to yield 1.1547 g (62%) of 4-{[(2,4-dichloro-thiazol-5-yl)methyl]-amino}-piperidine-1-carboxylic acid tert-butyl ester: mass spectrum (ion spray): m/z=366.1 (M+1); 1H NMR (CDCl3): δ=4.04 (br s, 2H), 3.96 (s, 2H), 2.87-2.81 (m, 2H), 2.72-2.65 (m, 1H), 1.90-1.86 (m, 2H), 1.48-1.39 (m, 10H), 1.33-1.23 (m, 2H).

1. additionPour
2. extractionextract with ethyl acetate (3×100 mL)
3. dry with materialDry the ethyl acetate over sodium sulfate
4. filtrationfilter off the sodium sulfate
5. concentrationConcentrate on a rotary evaporator
6. custompurify the crude product by flash chromatography on silica gel eluting with 35% ethyl acetate/hexanes