Sulfuric Acid → 3-Methyl-2-(phenylformamido)butanoic acid

Participants

Reaction Steps

5.1 kg. (36.28 moles) of benzoyl chloride is added portionwise to a mixture of 3.5 kg. (29.88 moles) of DL-valine, 39.0 1. of 2N. sodium hydroxide solution (78 moles) and 7 1. of tetrahydrofuran stirred at ~10° C. at a rate such that the temperature is maintained at 10° -15° C., and the reaction mixture is warmed to ~20° C. and stirred at ~20° C. for 3 hours, the reaction mixture being stirred under nitrogen throughout. 1.4 1. of concentrated sulfuric acid is carefully added at a rate such that the temperature does not exceed 25° C., and the mixture is cooled to ~5°-10° C. and stirred at this temperature for about 30 minutes to obtain a solid. (If necessary, the mixture is seeded.) The resulting solid is collected by filtration, washed three times with 20 1. portions of hot water, washed three times with 20 1. portions of hexane and dried at 40° C. and reduced pressure for ~12 hours to obtain the product (6.4 kg.), m.p. 123°-126° C.

Provenance & Evidence