4-Methylmorpholine → N-benzyloxy 2(R)-[(3,4-methylendioxybenzyl)-(2,6-dimethyl-4-methoxybenzenesulfonyl)amino]-3-methanesulfonylamino-propionamide

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Reaction Steps

To a mixture of 2(R)-[(3,4-methylendioxybenzyl)-(2,6-dimethyl-4-methoxybenzenesulfonyl)amino]-3-methanesulfonylamino-propionic acid (1 g, 1.9 mmol), O-benzylhydroxylamine (0.95 ml, 6 mmol) and 1-hydroxybenzotriazole hydrate (370 mg, 1.9 mmol), and N-methylmorpholine (0.7 ml, 5.7 mmol) in anhydrous dimethylformamide (20 ml) was added 1-ethyl-3(3-dimethylamino)-propyl carbodiimide hydrochloride salt. The mixture was stirred overnight and then condensed on the roto-evaporator. The remainder was taken up in ethyl acetate (60 ml) and partitioned with an equal volume of 5% aqueous hydrochloric acid. The ethyl acetate phase was collected and washed consecutively with equal volumes of 5% sodium bicarbonate and brine. The aqueous phases were back extracted with ethyl acetate (2×60 ml) and the organic layers combined, dried with magnesium sulfate, filtered and condensed. The residue was purified by preparative thin layer chromatography using 65% ethyl acetate-hexanes as eluant providing N-benzyloxy 2(R)-[(3,4-methylendioxybenzyl)-(2,6-dimethyl-4-methoxybenzenesulfonyl)amino]-3-methanesulfonylamino-propionamide as a yellow viscous oil (591 mg).

Provenance & Evidence