反应详情

To a solution of 4-(5-cyano-benzooxazol-2-ylamino)-piperidine-1-carboxylic acid tert-butyl ester (6.62 g, 19.33 mmol, 1.0 equiv) in dichloromethane (100 mL) was added trifluoro-acetic acid (7.4 mL, 11.03 g, 96.7 mmol, 5.0 equiv). After stirring under Ar at rt for 18 h excess trifluoro-acetic acid was removed under reduced pressure and the crude solid taken up in dichloromethane (100 mL) and water (100 mL). The pH was adjusted to 10 by addition of a conc. solution of K2CO3 and the solution extracted with dichloromethane/2-propanol (4:1, 3×50 mL). The combined organic phases were dried over MgSO4, the organic solvent evaporated under reduced pressure and the crude reaction product purified with column chromatography on silica eluting with a gradient of dichloromethane/methanol (100:0→95:5) containing 33% of NH4OH to yield 4.36 g (93%) of the title compound. MS (ESI): 243.1 [M+H]+.

1. customwas removed under reduced pressure
2. additionThe pH was adjusted to 10 by addition of a conc. solution of K2CO3
3. extractionthe solution extracted with dichloromethane/2-propanol (4:1, 3×50 mL)
4. dry with materialThe combined organic phases were dried over MgSO4
5. customthe organic solvent evaporated under reduced pressure
6. customthe crude reaction product
7. custompurified with column chromatography on silica eluting with a gradient of dichloromethane/methanol (100:0→95:5)
8. additioncontaining 33% of NH4OH