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Enzymic Synthesis of Peptide Bonds 5539 Catalytic Hydrogenolysis.-A solution of 4.77 g. of the distearoyl or 4.43 g. of the dipalmitoyl bis-(glycol)-phosphoric acid phenyl ester (6 mmoles) in a mixture of 95 ml. of chloroform and 20 ml. of 99% ethanol to which had been added 0.91 g. (4 mmoles) of platinic oxide (Adams catalyst) was shaken vigorously in an all-glass hydrogenation vessel in an atmosphere of hydrogen at an initial pressure of 40-50 cm. of water until the absorption of hydrogen ceased. In approximately one hour the theoretical amount of hydrogen (24 mmoles) had been consumed. After replacing the hydrogen with nitrogen and removing the catalyst, the solvents were distilled off under reduced pressure at a bath temperature of 30-35°. The bis-(glycol)-phosphatidic acid was washed with three 50-ml. portions of dilute acetic acid (10%) and was dried in vacuo (0.01 mm.) over solid sodium hydroxide. Both phosphatidic acids were free of potassium.Distearoyl-bis-(glycol)-phosphoric Acid.-For purification the crude distearoyl-(glycol)-phosphoric acid weighing 4.09 g. (95% of theory) was triturated with 35 ml. of 99% ethanol, the mixture was separated by centrifugation and the solid was recrystallized from 140 ml. of boiling 99% ethanol. The bis-(glycol)-phosphatidic acid was recovered in a yield of 75% (3.07 g.) and melted from 92.5-93.5°. At room temperature the distearoyl bis-(glycol)-phosphoric acid is insoluble in ether or acetone, very slightly soluble in methanol, ethanol, ethyl acetate, tetrachloromethane, petroleum ether or benzene, but readily soluble in chloroform. The substance is also readily soluble in warm methanol, ethanol, acetone, ethyl acetate, tetrachloromethane, petroleum ether (b.p. 100-120°) and benzene.

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