Monobasic potassium phosphate → Methyl 2-[4-[6-(2-ethylhexanamido)indol-1-ylmethyl]-3-methoxybenzoyl]-2-phenylsulphonylacetate

Participants

Reaction Steps

A solution of lithium diisopropylamide (6.0 ml of a 0.5M solution in THF) was added to a solution of methyl 2-(phenylsulphonyl)acetate (650 mg) in THF (5.0 ml) at -78° C. A solution of 4-[6-(2-ethylhexanamido)indol-1-ylmethyl]-3-methoxybenzoic N,N-diphenylcarbamic anhydride (A) (617 mg) in THF (5.0 ml) was added to the resultant mixture. After 2 hours, the reaction solution was allowed to warm to room temperature overnight and an excess of a solution of potassium dihydrogen phosphate was then added. The solvent was evaporated and the residue partitioned between water and ethyl acetate. The organic phase was separated, dried (Na2SO4) and evaporated. The resultant yellow oil was purified by chromatography on silica gel (42 g) using an increasing gradient of ether:methylene chloride (up to 1:19 v/v ether:methylene chloride). The title compound was thus obtained as an oil which was crystallized by treatment with methyl t-butyl ether to give an off-white solid (172 mg, 17%); mp 148°-149° C.

Provenance & Evidence