Sodium Hydroxide → Dl-Phenylalanine

Beteiligte Stoffe

Reaktionsschritte

95.1 g (0.5 mole) of 5-benzyl-hydantoine are dissolved in a solution of 87 g of sodium hydroxide and 400 ml of water, whereupon 300 ml of cellosolve are added. The reaction mixture is heated to boiling for 48 hours, the water and the cellosolve are distilled off in vacuo (30 Hgmm, 80° C.), the solid residue is dissolved in a small amount of water and acidified with concentrated hydrochloric acid (pH 2). The solution is treated with activated charcoal and the pH is adjusted to 6 with a concentrated ammonium hydroxide solution. The mixture is allowed to stand for some hours at 5° C. The precipitated product is filtered off, washed with cold water and cold ethanol. Thus 63.4 g of the desired airdry compound are obtained, yield 77%, mp.: 245°-255° C. Purity: 97.9% according to HPLC.

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