Ammonia → HCID 21141077, compound

Participants

Reaction Steps

S-Benzyl-N-benzyloxycarbonyl-L-cysteinyl-L-prolyl-L-leucyl-glycinamide (300 mg.) was dissolved in 35 ml. of anhydrous liquid ammonia and hydrogenated in the presence of freshly prepared palladium black (ca 0.1g.) and triethylamine (0.28 ml.) at the boiling point of the solvent. The reaction was followed by thin layer chromatography (solvent system CCl4 /CH3OH/CH3COOH8:1:1) which showed incomplete reaction (50-60%) after 6 hours. Evaporation of ammonia under nitrogen was followed by addition of methanol (10 ml.) and stirring for 10 min. The catalyst was then removed by filtration and washed with methanol (10 ml.). The combined filtrate and washings were passed through a column (1.2 × 10 cm) of Dowex 50 × 8 (H+ form) which was washed with methanol. The desired material was then eluted with 2N ammonium hydroxide-methanol (1:1) and the eluate evaporated in vacuo. Crystallization from water gave 95.2 mg. (42.3%); m.p. 130°-134°.

Provenance & Evidence