Hydrochloric Acid → (2S,3R,6S)-4-[4-(4-Hydroxy-4-methyl-pent-2-ynyloxy)-benzenesulfonyl]-2,6-dimethyl-morpholine-3-carboxylic acid hydroxyamide

Participants

Reaction Conditions

Reaction Steps

Hydroxylamine hydrochloride (2.76 g, 39.7 mmol) was dissolved in methanol (14 mL) by heating to 85° C. This solution was added to a solution of potassium hydroxide (3.31 g, 59.0 mmol) in methanol (8.3 mL) and the resulting white slurry stirred for 15 minutes. The white precipitate was removed by filtration and the filtrate was added to a flask containing (2S,3R,6S)-4-[4-(4-hydroxy-4-methyl-pent-2-ynyloxy)-benzenesulfonyl]-2,6-dimethyl-morpholine-3-carboxylic acid methyl ester (258 mg, 0.607 mmol) and the reaction was stirred at room temperature for 1.5 hours. 1 N hydrochloric acid (20 mL) was then added drop wise and the methanol was removed in vacuo. The aqueous residue was extracted with ethyl acetate (3×50 mL) and the combined organic fractions were washed with brine ( 30 mL), dried over anhydrous magnesium sulfate and concentrated in vacuo. The resulting white solid was chromatographed on a Biotage column® (40s) eluting with ethyl acetate and hexanes (7:1, the column was pretreated with 0.5% triethyl amine in above solvent system) to yield the title compound (54.8 mg, 21%, 2 steps). MS: Calculated for C19H26N2O7S (M+H): 427.16 and (M−H): 425.14. Found: 427.0 and 425.2.

Provenance & Evidence