[S:1](Cl)(Cl)=[O:2].[OH:5][CH:6]([CH3:17])[CH2:7][CH2:8][NH:9][C:10](=[O:16])[O:11][C:12]([CH3:15])([CH3:14])[CH3:13].N1C=CC=CC=1.C(OCC)(=O)C>C(#N)C.CN(C)C1C=CN=CC=1>[CH3:17][CH:6]1[O:5][S:1](=[O:2])[N:9]([C:10]([O:11][C:12]([CH3:13])([CH3:15])[CH3:14])=[O:16])[CH2:8][CH2:7]1
To a stirred solution of thionyl chloride (2.0 mL, 27.9 mmol) in acetonitrile (15 mL) cooled to −45° C. is added a solution of tert-butyl (3-hydroxybutyl)carbamate (2.1 g, 11.2 mmol) in acetonitrile (20 mL) by syringe over 10 min, keeping the internal temperature below −40° C. 4-Dimethylaminopyridine (136 mg, 1.1 mmol) is added followed by the dropwise addition of pyridine (4.5 mL, 55.8 mmol, keeping the temperature below −40° C. The addition takes 90 min. Ethyl acetate (50 mL) is added to the suspension and the mixture is filtered at −35° C. to remove the solid and the solid which is washed with EtOAc before it is discarded. The filtrates are combined, and saturated Na2HPO4 solution (20 mL) is added. The mixture is stirred vigorously for 30 min and the organic layer is separated, washed with 1M NaHSO4 to remove residual pyridine, dried (MgSO4) and concentrated to afford the title compound (2.52 g, 96%) as an oil.
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