Hydrochloric Acid → tert-butyl 2(R)-(2,6-dimethyl-4-methoxybenzene sulfonylamino)-3-phthalimido-propionate

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Reaction Steps

To a stirred solution of tert-butyl-2(R)-amino-3-phthalimido-propionate (5.7 g, 19.63 mmol) in dry acetonitrile (60 ml) was added trimethylsilylcyanide (8.6 ml, 68.7 mmol). After 5 minutes 2,6-dimethyl-4-methoxybenzenesulfonyl chloride (4.84 g, 20.6 mmol) was added in one portion. The material was stirred at ambient temperature for 1 hour and then ethyl acetate (80 ml) was added and the mixture was transferred to a seperatory funnel. The organic phase was partioned with aqueous hydrochloric acid (1.5%, 100 ml), collected and washed with an equal volume of brine. The aqueous phases were back extracted with ethyl acetate (2×80 ml) and the organic phases combined, dried (magnesium sulfate), filtered and condensed. The residue was chromatographed (flash silica gel, 30% ethyl acetate-hexanes) to provide tert-butyl 2(R)-(2,6-dimethyl-4-methoxybenzene sulfonylamino)-3-phthalimido-propionate as white semi-solid (6.9 g).

Provenance & Evidence