Citric Acid → 5-Oxazolidinepropanoic acid, 3-[(1,1-dimethylethoxy)carbonyl]-4-[(2S)-2-[[4-methoxy-3-(3-methoxypropoxy)phenyl]methyl]-3-methylbutyl]-2,2-dimethyl-alpha-(1-methylethyl)-, (alphaS,4S,5S)-

Participants

Reaction Steps

53 g of 3-tert-butoxycarbonyl-5(S)-(2(S)-formyl-3-methyl-butyl)-4(S)-{2(S)-isopropyl-3-[4-methoxy-3-(3-methoxypropyloxy)-phenyl]-propyl}-2,2-dimethyl-1,3-oxazolidine are dissolved in 470 ml of toluene, and, at 0° C., 470 ml of water, 79.1 g of potassium permanganate and 9.7 g of tetrabutylammonium bromide are added in succession thereto. The reaction mixture is stirred for a further 48 hours at 0°-5° C., and then, at 10° C., 1.2 liters of 10% sodium sulfite solution are added. After a further 30 minutes, 1.95 liters of 10% citric acid solution and 1.2 liters of water are added. The product is extracted by repeated extraction with ethyl acetate. The extracts are concentrated by evaporation and purified by FC (2.3 kg of silica gel, ethyl acetate/hexane=3:7). The title compound is obtained: Rf (ethyl acetate/hexane=1:2)=0.21.

Provenance & Evidence