Thioglycolic Acid → (S)-3-[(S)-2-(4-Hydroxy-phenyl)-2,3-dihydro-benzo[1,4]dioxin-6-yl]-2-((S)-1-phenyl-propylamino)-propionic acid methyl ester

Participants

Reaction Steps

(S)-3-[(S)-2-(4-Acetoxy-phenyl)-2,3-dihydro-benzo[1,4]dioxin-6-yl]-2-[(4-nitro-benzenesulfonyl)-((S)-1-phenyl-propyl)-amino]-propionic acid methyl ester (230 mg) was dissolved in 3 mL dry DMF, then, mercaptoacetic acid and DBU were added at rt. The reaction stirred over night, and was partitioned between saturated aqueous NaHCO3 and diethyl ether. The organic layer was washed successively with aqueous NaHCO3, water, and brine, then was dried with Na2SO4 and evaporated. The residue was purified by silica gel flash chromatography (9:1 to 8:2 hexanes/EtOAc) to give 120 mg desired product. LCMS (m/z): 449.

Provenance & Evidence