反应详情

温度

-20 °C

To the solution of 4-[(3-hydroxypropyl)amino]benzonitrile (from step (i) Alternative 3 above, assumed 43.65 g, 247.7 mmol, 1.0 eq) in dichloromethane (360 mL total solution volume) was added, sequentially, triethylamine (52 mL, 37.60 g, 371.55 mmol, 1.5 eq) and trimethylamine hydrochloride (11.89 g, 123.85 mmol, 0.5 eq) in one portion. The yellow solution was cooled to −20° C. (using an acetone/dry ice bath or a cold plate), and treated with a solution of benzenesulfonyl chloride (32 mL, 43.74 g, 247.7 mmol, 1.0 eq) in dichloromethane (220 mL, 5 vols with respect to the cyanoalcohol) via a pressure equalising dropping funnel. The solution was added portionwise such that the internal temperature did not exceed −14° C. The addition took 25 minutes to complete. The mixture was then stirred for 35 minutes at between −15 and −10° C. Water (365 mL) was added and the temperature rose to 10° C. The mixture was cooled back to 0+ C. and stirred vigorously for 15 minutes. The organic layer (volume 570 mL) was collected and distilled at atmospheric pressure to remove DCM (450 mL, pot temperature 40–42° C., still-head temperature 38–39° C.). Ethanol (250 mL) was added, and the solution was allowed to cool to below 30° C. before turning on the vacuum. More solvent was removed (40 mL was collected, pressure 5.2 kPa (52 mbar), pot and still-head temperatures were 21–23° C.), and the product gradually came out of solution. The distillation was stopped at this point, and more ethanol (50 mL) was added. The mixture was warmed (hot water bath at 50° C.) to 40° C. to dissolve all the solid, and water (90 mL) was added slowly via a dropping funnel. The solution was stirred slowly at room temperature (20° C.) overnight (15 hours), by which time some product had crystallised out. The mixture was cooled to −5° C. (ice/methanol bath) and stirred at this temperature for 20 minutes before collecting the pale yellow solid by filtration. The solid was washed with an ethanol/water mixture (42 mL EtOH, 8 mL H2O), and suction dried for 30 minutes before drying to constant weight in the vacuum oven (40° C., 72 hours). The mass of crude product obtained was 47.42 g (149.9 mmole, 60%). Ethanol (160 mL, 8 vols) was added to the crude product (20.00 g, 63.22 mmol, 1.0 eq). The mixture was stirred under nitrogen and warmed to 40° C. using a hot water bath. On reaching this temperature, all of the solid had dissolved to give a clear, yellow solution. Water (60 mL, 3 vols) was added dropwise over a period of 10 minutes, whilst the internal temperature was maintained in the range 38–41° C. The water bath was removed, and the solution was allowed to cool to 25° C. over 40 minutes, by which time crystallisation had begun. The mixture was cooled to −5° C. over 10 minutes, then held at this temperature for a further 10 minutes. The pale yellow solid was collected by filtration, suction dried for 10 minutes, then dried to constant weight in a vacuum oven (40° C., 15 hours). The mass of sub-title compound obtained was 18.51 g (58.51 mmol, 93% (from the crude product)).

1. additionThe solution was added portionwise such that the internal temperature
2. customdid not exceed −14° C
3. additionThe addition
4. customrose to 10° C
5. temperatureThe mixture was cooled back to 0+ C
6. stirringand stirred vigorously for 15 minutes
7. customThe organic layer (volume 570 mL) was collected
8. distillationdistilled at atmospheric pressure
9. customto remove DCM (450 mL, pot temperature 40–42° C., still-head temperature 38–39° C.)
10. additionEthanol (250 mL) was added
11. temperatureto cool to below 30° C.
12. customMore solvent was removed (40 mL
13. customwas collected
14. customwere 21–23° C.
15. distillationThe distillation
16. additionwas added
17. temperatureThe mixture was warmed (hot water bath at 50° C.) to 40° C.
18. dissolutionto dissolve all the solid, and water (90 mL)
19. additionwas added slowly via a dropping funnel
20. stirringThe solution was stirred slowly at room temperature (20° C.) overnight (15 hours)
21. customby which time some product had crystallised out
22. temperatureThe mixture was cooled to −5° C. (ice/methanol bath)
23. stirringstirred at this temperature for 20 minutes
24. custombefore collecting the pale yellow solid
25. filtrationby filtration
26. washThe solid was washed with an ethanol/water mixture (42 mL EtOH, 8 mL H2O), and suction
27. customdried for 30 minutes
28. custombefore drying to constant weight in the vacuum oven (40° C., 72 hours)
29. customThe mass of crude product obtained
30. stirringThe mixture was stirred under nitrogen
31. temperaturewarmed to 40° C.
32. dissolutionall of the solid had dissolved
33. customto give a clear, yellow solution
34. temperaturewas maintained in the range 38–41° C
35. customThe water bath was removed
36. temperatureto cool to 25° C. over 40 minutes, by which time crystallisation
37. temperatureThe mixture was cooled to −5° C. over 10 minutes
38. waitheld at this temperature for a further 10 minutes
39. filtrationThe pale yellow solid was collected by filtration, suction
40. customdried for 10 minutes
41. customdried to constant weight in a vacuum oven (40° C., 15 hours)