反应详情

A solution of (1S,4R)-tert-butyl 3-oxo-2-azabicyclo[2.2.1]hept-5-ene-2-carboxylate (part a of this example, 95.50 g, 0.456 mole) in tetrahydrofuran (500 ml)-water (50 ml) was added over 10 minutes to a vigorously stirred solution of sodium borohydride (Aldrich, 21.96 g, 0.580 mole as 99%) in water (100 ml). The temperature was maintained below 35° C. After 2 hours, the solution was cooled to maintain the temperature below 25° C. while concentrated hydrochloric acid (50 ml) was added over 10 minutes. Additional water (100 ml) was added to dissolve solid and the solution was extracted with toluene (4×300 ml). The combined organic layers were washed with 9:1 saturated sodium sulfate/saturated sodium carbonate (200 ml) and dried (sodium sulfate). Evaporation of solvents under reduced pressure left a colorless syrup which crystallized on stirring with hexanes (200 ml) to provide title compound as a fine white powder (87.16 g, 90%), m.p. 72–73° C.; 1H-NMR (DMSO-d6) δ 6.78 (d, J=7.6 Hz, 1H), 5.80 and 5.60 (two m, 2H), 4.58 (t, J=5.25 Hz, 2H), 4.45 (m, 1H), 3.35 (m overlapping water), 2.60 (m, 1H), 2.30 (m, 1H), 1.38 (s, 9H), 1.20 (m, 1H); [α]58920+2.80° (c 5.0, methanol).

1. temperatureThe temperature was maintained below 35° C
2. temperaturethe solution was cooled
3. additionwas added over 10 minutes
4. dissolutionto dissolve solid
5. extractionthe solution was extracted with toluene (4×300 ml)
6. washThe combined organic layers were washed with 9:1 saturated sodium sulfate/saturated sodium carbonate (200 ml)
7. dry with materialdried (sodium sulfate)
8. customEvaporation of solvents under reduced pressure
9. waitleft a colorless syrup which
10. customcrystallized