Chloromethyl methyl sulfide → N-Tert-butoxycarbonyl-2(R,S)-methyl-4(S)-hydroxy-5(S)-amino-7(S)-isopropyl-8-[3-(methylthio-methoxy)-4-tert-butyl-phenyl]-octanoic acid (N-butyl)amide

Participants

Reaction Steps

A solution of 100 mg of N-tert-butoxycarbonyl-2(R,S)-methyl-4(S)-hydroxy-5(S)-amino-7(S)-isopropyl-8-(3-hydroxy-4-tert-butyl-phenyl)-octanoic acid (N-butyl)amide (Example 5a) in 5 ml of dimethylformamide is added dropwise to a suspension, stirred at room temperature, of 7.6 mg of a 65% NaH dispersion in 3 ml of dimethylformamide. The reaction mixture is stirred for a further 30 minutes at more temperature and then a solution of 0.017 ml of chlorodimethyl sulfide in 2 ml of dimethylformamide is added thereto. The reaction mixture is stirred for a further 24 hours and then concentrated by evaporation. The residue is partitioned between ether and water. The organic phases are concentrated by evaporation and the title compound is obtained from the residue by FC (12 g of silica gel, dichloromethane/diethyl ether=2:1): Rf (dichloromethane/diethyl ether=2:1)=0.33.

Provenance & Evidence