反应详情

Spiro[4H-3,1-benzoxazine-4,4′-piperidin]-2(1H)-one (A4) (410 mg, 1.88 mmol) was dissolved in anhydrous 1,2-dichloroethane (10 mL) and treated with tert-butyl 4-oxopiperidine-1-carboxylate (via) (562 mg, 2.82 mmol), glacial acetic acid (226 mg, 3.76 mmol) and sodium triacetoxyborohydride (797 mg, 3.76 mmol). The reaction was stirred under nitrogen at room temperature for 72 hours. The reaction was concentrated under reduced pressure and the residue partitioned between 1.0 N HCl (50 mL) and diethyl ether (25 mL). The aqueous layer was separated and washed with diethyl ether (2×25 mL), basified with 1.0 N NaOH (aq) and extracted with dichloromethane (3×50 mL). The pooled extracts were washed with saturated brine, dried over Na2SO4 and filtered. The filtrate was concentrated in vacuo to afford tert-butyl 4-(2-oxo-1,2-dihydrospiro[benzo[d][1,3]oxazine-4,4′-piperidine]-1′-yl)piperidine-1-carboxylate (vib) as a crystalline white solid. LC/MS m/z 402.2 [M+H]+, retention time 1.84 min (RP-C18, 10-99% CH3CN/0.05% TFA).

1. concentrationThe reaction was concentrated under reduced pressure
2. customthe residue partitioned between 1.0 N HCl (50 mL) and diethyl ether (25 mL)
3. customThe aqueous layer was separated
4. washwashed with diethyl ether (2×25 mL)
5. extractionextracted with dichloromethane (3×50 mL)
6. washThe pooled extracts were washed with saturated brine
7. dry with materialdried over Na2SO4
8. filtrationfiltered
9. concentrationThe filtrate was concentrated in vacuo