Triphenylphosphine → HCID 86638107, compound

Participants

Reaction Steps

Triphenylphosphine (12.0 g, 45.9 mmol) and diisopropyl azodicarboxylate (9.88 g, 45.9 mmol) were added at room temperature to a solution of 3-[tert-butoxycarbonyl-((R)-2-hydroxy-1-methyl-ethyl)-amino]-propionic acid ethyl ester in tetrahydrofuran (600 ml), then after 2 min diphenylphorphoryl azide (12.6 g, 45.9 mmol) was added. After 16 h the reaction mixture was concentrated and the residue purified by chromatography (SiO2; heptane-ethyl acetate gradient) to afford slightly impure 3-[tert-butoxycarbonyl-((R)-2-azido-1-methyl-ethyl)-amino]-propionic acid ethyl ester (8.82 g). This was dissolved in methanol (880 ml), then after addition of palladium (10% on activated charcoal, 1.6 g) and potassium carbonate (42.6 g, 308 mmol) the reaction mixture was hydrogenated at room temperature and atmospheric pressure for 16 h. Insoluble material was removed by filtration and the filtrate concentrated. Chromatography (SiO2; heptane/ethyl acetate 1:1, then dichloromethane/methanol/25% aq. ammonia solution 97.5:2.5:0.25) produced the title compound (2.20 g, 21%). White solid, MS (ISP)=229.4 (M+H)+.

Provenance & Evidence