4-Methylmorpholine → N-benzyloxy-2(R)-[(3,4-methylendioxybenzyl)-(2,6-dimethyl-4-methoxybenzenesulfonyl)amino]-3-[(2-pyrrol-1-yl)phenylcarbonylamino]-propionamide

Participants

Reaction Steps

To a mixture of 2(R)-[(3,4-methylendioxybenzyl)-(2,6-dimethyl-4-methoxybenzenesulfonyl)amino]-3-[(2-pyrrol-1-yl)phenylcarbonylamino]-propionic acid (approximately 1.3 mmol), O-benzylhydroxylamine (0.6 ml, 3.9 mmol) and 1-hydroxybenzotriazole hydrate (199 mg, 1.3 mmol), and N-methylmorpholine (0.44 ml, 3.9 mmol) in anhydrous dimethylformamide (20 ml) was added 1-ethyl-3(3-dimethylamino)-propyl carbodiimide hydrochloride salt (375 mg, 1.95 mmol). 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 1.5% aqueous hydrochloric acid. The ethyl acetate phase was collected and washed consecutively with equal volumes of 5% sodium bicarbonate and then 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 TLC (2% methanol-methylene chloride) providing N-benzyloxy-2(R)-[(3,4-methylendioxybenzyl)-(2,6-dimethyl-4-methoxybenzenesulfonyl)amino]-3-[(2-pyrrol-1-yl)phenylcarbonylamino]-propionamide as a light yellow foamy solid (490 mg).

Provenance & Evidence