Benzyl Alcohol → 2-(N-carbobenzyloxyaminosulfonyl)aminopentanoic acid methyl ester

Participants

Reaction Steps

To a stirred solution of 7.36 ml (84.9 mmol) of chloro-sulfonyl isocyanate in 150 ml of methylene chloride was added benzyl alcohol (8.82 ml, 84.7 mmol) at 0° C. over a period of 35 minutes. After stirring the above solution for 2 hours at this temperature, a solution of 15.62 g (93.25 mmol) of DL-valine methyl ester hydrochloride in methylene chloride containing triethylamine (36.36 ml) was added at 0°-5° C., and the resulting mixture was stirred overnight allowing the mixture to warm to room temperature. The reaction mixture was poured into 600 ml of a 10% aq. HCl solution, saturated with sodium chloride, and the organic layer was separated. The aqueous layer was extracted with methylene chloride (2×200 ml) and the combined organic layer was washed with brine, dried and concentrated in vacuo to yield 30 g of N-(carbobenzyloxyaminosulfonyl)-DL-valine methyl ester (Formula XIV: R=CH3 ; R1 =H; R2 =isopropyl; R3 =H) as a solid.

Provenance & Evidence