[NH2:1]/[C:2](=[N:16]\[OH:17])/[CH:3]1[CH2:8][CH2:7][CH2:6][CH2:5][N:4]1[C:9]([O:11][C:12]([CH3:15])([CH3:14])[CH3:13])=[O:10].[CH3:18][CH2:19]N(C(C)C)C(C)C.C(Cl)(=O)C>C(#N)C>[CH3:18][C:19]1[O:17][N:16]=[C:2]([CH:3]2[CH2:8][CH2:7][CH2:6][CH2:5][N:4]2[C:9]([O:11][C:12]([CH3:14])([CH3:13])[CH3:15])=[O:10])[N:1]=1In a 16 mL vial, tert-butyl 2-[(Z)-amino(hydroxyimino)methyl]piperidine-1-carboxylate (150 mg, 0.62 mmol; which may be prepared as described in Step 1) was dissolved in acetonitrile (6.2 mL) and cooled at 0° C. under nitrogen. DIPEA (324 μL, 1.86 mmol) and acetyl chloride (88 μL, 1.24 mmol) were added dropwise and the reaction mixture was allowed to warm to room temperature then heated to 100° C. for 4 h, cooled and concentrated. The residue was taken up in EtOAc and water. The two layers were separated and the aqueous phase extracted with EtOAc. The combined organics were dried on Na2SO4 and concentrated. The residue was taken up in o-xylene (7 mL) and heated to 150° C. for 3 h then concentrated. The crude mixture was purified on column chromatography (eluent: Pentane/EtOAc 7/3) to give the product (55 mg, 33%) as a yellow oil.
Wird geladen…
