Hydrochloric Acid → Methyl 2-[4-[5-(2-cyclopentylacetamido)-1-ethylindol-3-ylmethyl]-3-methoxybenzoyl]-2-phenylsulfonylacetate

Participants

Reaction Steps

A solution of potassium bis(trimethylsilyl)amide (7.1 ml of a 0.8M solution in toluene) was added to a solution of methyl 2-(phenylsulfonyl)acetate (1.24 g) in tetrahydrofuran (THF) (9.0 ml) at -78° C. This mixture was then added to a solution of 4-[5-(2-cyclopentylacetamido)-1-ethylindol-3-ylmethyl]-3-methoxybenzoic N,N-diphenylcarbamic anhydride (E) (600 mg) in THF at -78° C. The reaction solution was allowed to warm to room temperature overnight and saturated potassium dihydrogen phosphate (20 ml) was then added. The mixture was made acidic to pH 4 with the addition of 1N HCl and partitioned with ethyl acetate. The organic layer was washed with water and saturated brine, dried (MgSO4) and evaporated. The residue was purified by chromatography on silica gel (41 g) using chloroform as the eluent. The title compound was obtained as an oil which was crystallized from methyl t-butyl ether/hexane to give a pale yellow solid (64.5 mg, 10%); mp 78°-80° C.

Provenance & Evidence