Acetic Anhydride → L-aspartyl-L-phenylalanine methyl ester hydrochloride dihydrate

Participants

Reaction Conditions

Reaction Steps

0.2 parts of magnesium acetate were dissolved in 11.4 parts by volume of acetic acid. To this solution was added 9.9 parts by volume of acetic anhydride, 120 parts by volume of toluene, and 21.72 parts of N-acetoacetylaspartic acid. The resulting mixture was heated at 50° C. under nitrogen for 1.5 hours, then cooled to 20°-25° C. A solution containing 17.92 parts L-phenylalanine methyl ester in 30 parts by volume of toluene was added dropwise over a 20 minute period and the mixture stirred overnight. 6.95 parts of hydroxylamine hydrochloride in 100 parts by volume of water was added and stirring was continued for 2.5 hours. The aqueous layer was separated, extracted four times with 50 parts by volume of methylene chloride and cooled to 5° C. 15 parts by volume of concentrated hydrochloric acid were added and the mixture stirred at 5° C. for 1.5 hours. The precipitate was collected on a filter and pulled dry overnight to give 25.93 parts of L-aspartyl-L-phenylalanine methyl ester hydrochloride dihydrate.

Provenance & Evidence