Citric Acid → HCID 70064868, compound

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Reaction Steps

N-{1-[3-(N2 -Methanesulphonyl-N6 -t-butyloxycarbonyl-(S)-lysyl-amino)-2(R,S)-t-butyloxycarbonylpropyl]-1-cyclopentanecarbonyl}-O-t- butyl-(S)-tyrosine ethyl ester (2.21 g, 2.68 mmol) was dissolved in acetone (5.5 ml) and then a 1N aqueous solution of sodium hydroxide (5.36 ml, 5.38 mmol) was added. After stirring for 10 minutes at room temeprature the solution was acidified to pH4 with aqueous citric acid (10%). The acetone was then removed on a rotary evaporator and the residue extracted with ethyl acetate (50 ml). The organic phase was separated, washed with saturated brine, dried over magnesium sulphate and the solvent removed under reduced pressure to yield the title compound as a white foam (1.89 g, 88%). Found: C,58.49; H,8.01; N,6.64. C19H64N4O11S requires C,58.77; H,8.09; N,7.03%.

Provenance & Evidence