A. E. Gal, F. J. Fash
Mar 1, 1977
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Journal
Lipids
Abstract
Sir: Phosphorylcholine is found in human and animal tissues and body fluids. It is a substantial consti tuent of the nervous tissue and plays an important role in phospholipid biosynthesis (1-3). It is also used as an intermediate for the synthesis of organic compounds having a phosphorylcholine moiety (4). Phosphorylcholine has been prepared from choline ch lo r ide and phosphoric acid (5-6), from diphenylphosphorylcholine chloride (7), and from phenylcholine phosphate (8). These previously published methods are not well suited for the preparation of phosphorylcholine in gram quantities. The present letter describes the transformation of the commercially available calcium monochloride salt by a simple technique and in good yield. The method can be scaled up easily; it can also be u sed for the preparation of radioactively labeled compound. The exchange of the chloride for hydroxide was effected by silver carbonate, and the calcium ions were replaced through the use of a weakly acidic methacrylic acid polymer resin with carboxylic groups. Stronger acidic cation exchangers would react with the anionic moiety of the liberated compound. Phophorylcholine was obtained in low yield by treatment of the calcium monochloride salt with a mixture of weakly acid and basic ion exchange resins (9). The present method also describes a new thin layer chromatographic system using Silica Gel G plates. P r o c e d u r e : Phosphorylcholine chloride calcium sa l t 4 H20, 66 g (0.2 mol), (Sigma Chemical Co., St. Louis, MO) was dissolved in 1 liter of water. To this solution was added 41.4 g (0.15 mol) silver carbonate [Fisher Scientific Co., Pittsburgh, PA, or it was prepared according to (10)] and the mixture was stirred for 16 hr in the dark. A filtered aliquot showed 0.12 mol of calcium ions, 6 mmol of residual silver ions and the absence of chloride ions (determined by methods published, ref. 11). The mixture was passed through a 200 g Rexyn 102 H, (a methacrylic acid polymer with carboxylic group from Fisher Scientific Co.) 100-200 mesh column (4 x 25 cm) which was then washed with 400 ml o f water. Tests for calcium ions in the effluent were negative. The pooled solutions of phosphorylcholine were evaporated at 40 C (16 mm Hg) with a rotary evaporator and the residue was then further dried at the same temperature at 0.1 mm Hg for 4 hr. It weighed 35 g (87%), and was recrystallized from 200 ml of ethanol yielding 21 g; mp 231-232C (decomp). Additional amounts of this compound could be obtained by reducing the volume of the mother liquor. A second recrystallization from 15 times (v/w) methanol-acetone (2:3) gave a product melting at 237-238 C (decomp.) (Taken on a ThomasHoover melting point apparatus and corrected). [Lit. (8); 234-238 C (decomp.)] . Phosphoryl-