Methanol → Methyl L-phenylalaninate hydrochloride

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Reaction Steps

Thionyl chloride (14 mL, 0.19 mol) was slowly added to a vigorously stirred -5° C. suspension of L-phenylalanine (26.28 g, 0.159 mol) in methanol (250 mL). After the addition of thionyl chloride was complete, the resulting homogeneous solution was allowed to warm to room temperature and was left stirring overnight. The reaction solvent was removed invacuo to produce a white solid. This solid was redissolved in methanol (100 mL) and the resulting solution was reconcentrated in vacuo to produce the product L-phenylalanine methyl ester hydrochloride (mp 158°-159° C., 34.10 g, 0.158 mol, 99.4%). A sample of this material was converted to the N-trifluoroacetylisopropyl ester using standard procedures. The resulting ester was found to contain 0.088% of the D-isomer by gc analysis on a Chirasil-Val™ chiral gc column (obtained from Applied Science). The 1H NMR of this synthetic material was identical with that of a commercial sample.

Provenance & Evidence