Sulfuric Acid → L-Phenylalanine, methyl ester

Reaktionsgleichung

S(=O)(=O)(O)O.[NH2:6][C@H:7]([C:15]([OH:17])=[O:16])[CH2:8][C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1.N[C@@H:19](C(O)=O)CC1C=CC=CC=1>CO>[CH3:19][O:16][C:15](=[O:17])[C@H:7]([CH2:8][C:9]1[CH:14]=[CH:13][CH:12]=[CH:11][CH:10]=1)[NH2:6]

Komponenten

Versuchsvorschrift

5.8 ml of 95% sulfuric acid was added to 33 ml of methanol and heat-refluxed. Subsequently, methanol was removed under reduced pressure and water was added to provide 15 ml of CH3SO4H solution. 2.7 g L-Phe and 0.3 g (D-Phe/L-Phe=11.1%) D-Phe were added thereto and dissolved by heat, following which was then cooled with ice. The separated crystals were isolated by suction filtration and washed with a small amount of cold water. Yield, 3.73 g. The results of HPLC analysis using an optically active column revealed that the crystals contained 1.66 g L-Phe and 0.049 g (D-Phe/L-Phe=2.9%) D-Phe. In addition, 41 mg of L-phenylalanine methyl ester was also produced as a result of esterification of L-Phe with the methanol remaining in the CH3SO4H solution.