Über eine vereinfachte Methode zur Darstellung von phosphorfreien Cerebrosiden und über die als Spaltprodukte auftretenden Fettsäuren 18. Mitteilung über Cerebroside
Previous attempts to separate cerebrosides from associated P-containing compounds by repeated recrystallizations have resulted in the loss of the more easily soluble cerebrosides. In the new method, 3.6 g. of a cerebroside fraction prepared from human brain according to the method of Klenk [see B. A. 17(7): entry 18011] are dissolved in 130 ml. pyridine. This soln. is filtered through a column containing 18 g. Al2O3 (standardized according to Brockmann). The filtrate is concd, under diminished pressure, the soln. treated with acetone and 2.2 g. P-free cerebroside recovered. The compound is recrystal-lized 3 times from chloroform-methanol (3:1), and 1.4 g. pure crystalline cerebron (CH93NO9) obtained. Fifty g. of an impure kerasin fraction which has been stored in the laboratory some yrs. are dissolved in 14 vols. pyridine. After 3 days, the soln. is filtered and poured through a column containing 50 g. Al2O3, and then through a 2d column containing 50 g. Al2O3, The soln. is then concd., treated with acetone and the precipitate recrystallized from 90% alcohol. From 50 g. of the initial kerasin fraction, 35 g. P-free kerasin fraction are obtained. In the P-free kerasin fraction, the following acids are shown to be present; palmitic, stearic, nervonic, n-hexacosenic, and probably C, C and high mol. wt. acids. It is concluded that hitherto unknown cerebrosides, such as stearyl sphingosine galactoside and palmityl sphingosine galactoside, are present in the brain.