[OH:1][C@H:2]([CH2:6][CH3:7])[C:3]([NH2:5])=[O:4].C(N(CC)CC)C.[CH3:15][S:16](Cl)(=[O:18])=[O:17]>O1CCCC1>[C:3]([C@H:2]([O:1][S:16]([CH3:15])(=[O:18])=[O:17])[CH2:6][CH3:7])(=[O:4])[NH2:5]To a mixture of (R)-2-hydroxybutyramide (4.2 g, 40.7 mmol) and triethylamine (6.2 ml, 44.8 mmol, 1.1 equiv.) in tetrahydrofuran (50 ml) is added drop wise at −40° C. methanesulfonic acid chloride (3.5 ml, 44.8 mmol, 1.1 equiv.). The mixture is allowed to warm to 20° C. and is filtered over magnesium sulfate (8 g). The cake is rinsed twice with tetrahydrofuran (2×20 ml) and combined filtrates are concentrated to dryness under reduced pressure to afford methanesulfonic acid (R)-1-carbamoyl-propyl ester (IIi) as a solid. (7.9 g, 106%, triethylamine hydrochloride salts are present).
Loading…
