Ammonia → benzyl 3-aminosulfonyl-2(R)-methylpropionate

Participants

Reaction Conditions

Reaction Steps

A 100 mL round bottom flask equipped with magnetic stir bar was charged with 1.22 g of benzyl 3-chlorosulfonyl-2(R)-methylpropionate in 15 mL CH2Cl2 and cooled to −78° C. To this solution was added to 10 mL of liquid ammonia at −78° C. After 20 minutes the reaction was warmed to room temperature, concentrated in vacuo to afford a white solid. The solid was slurried in ethyl acetate, filtered to remove inorganic salts and concentrated in vacuo to afford 1.08 g of benzyl 3-aminosulfonyl-2(R)-methylpropionate as a clear yellow oil. The crude product was used without further purification. Part B: 3-aminosulfonyl-2(R)-methylpropionic acid A 100 mL Fisher/Porter vessel was charged with 1.1 g of crude benzyl 3-aminosulfonyl-2(R)-methylpropionate in 35 mL MeOH and a catalytic amount of 10% Pd—C. The mixture was hydrogenated at 50 psi for 24 hours, filtered through Celite and concentrated in vacuo to yield 700 mg of 3-aminosulfonyl-2(R)-methylpropionic acid as a clear oil. The crude acid was used without further purification.

Provenance & Evidence