Chromatographic separation, identification, and analysis of phosphatides

Publisher Summary This chapter discusses the important reactions of the hydroxyl group. Knowledge of the relative reactivities of hydroxyl groups in carbohydrates is fundamental to a thorough understanding of carbohydrate chemistry. The chapter explains esterification, which forms the largest part of the literature since 1953 on selective reactions of carbohydrates. The common methods of esterification utilize an acid chloride or an acid anhydride as the reagent, but other acid derivatives often show different selectivities. An investigation pertinent to the subject of favored reactivity concerned the reactions of certain acyl halides with ethanol, in acetone or chloroform solution. The mixed-order nature of some of these reactions suggested that every rate-determining transition-state contained the substrate, the nucleophile (ethanol), and an acceptor— X—for hydrogen bonding, suitable acceptors being an acetone molecule, a chloride ion, or another ethanol molecule. The possibility that intramolecular hydrogen-bonding does not persist in pyridine and that the advantage of a bonded hydroxyl group would be lost, invalidates the explanation of favored reactivity. But if the hydrogen-bonding to pyridine is hindered in the transition state, intramolecular hydrogen-bonding could conceivably assume importance.

Relative Reactivities of Hydroxyl Groups in Carbohydrates

The chitinase system of a strain of Streptomyces griseus.

Formation of carboxamides by direct condensation of carboxylic acids and amines in alcohols using a new alcohol- and water-soluble condensing agent: DMT-MM

New analytical possibilities arise when glycerosphophatides are converted into diglyceride acetates or analogous compounds: In this less polar form the phospholipids can be subjected to the usual methods of triglyceride fractionation, including chromatography on silica gel mixed with silver nitrate. This opens a route to subfractionation of various glycerophosphatide classes, and makes analysis of the individual molecular species potentially possible in many cases. The same approach can also be applied to the analysis of sphingomyelins.

Individual molecular species of different phospholipid classes. Part II. A method of analysis

Some Fatty Acid Derivatives of D-Glucosamine

A method is described by which unsaturated fatty acid esters can be separated and identified by reversed-phase paper chromatography. The procedure is based upon the formation of the mercuric acetate addition compounds of the esters and the detection of the compounds on the chromatograms, using the sensitive color reaction with diphenylcarbazone. The application of this technique to the analysis of the component unsaturated acids of natural fats has been examined, and tetradecenoic acid in olive oil and hexadecenoic acid in linseed oil both formerly unidentified have been detected as the minor component acids by means of the method. The preliminary investigation on the absorption spectra of diphenylcarbazone complexes derived from the addition compounds has been made to bring the method into quantitative use.

Paper chromatography of unsaturated fatty acid esters as their mercuric acetate addition compounds

An Acyl Migration in Acetohalogenoglucosamines1

Paper chromatography of egg lecithins.

By reversed-phase paper chromatography, the simultaneous separations of all saturated and unsaturated fatty acids were successfully carried out on the same paper with the aid of p-bromophenacyl ester 2, 4-dinitrophenylhydrazones and their mercuric acetate addition compounds. When petroleum hydrocarbon (b. p. 140-170°) was used as the stationary solvent and methanol-acetic acid-petroleum hydrocarbon as the moving solvent, even saturated acids from C4 to C22, even monoethenoid acids from C10 to C22, and C18 series from stearic to linolenic were well separated, respectively. Similar separations were also attained on paper impregnated with decalin and olive oil. From the results of several applications, this method has been found to be effective for the analysis of the component acids in natural fats.

Yoshiyuki Inouye

Papers

Some Fatty Acid Derivatives of D-Glucosamine

Paper chromatography of unsaturated fatty acid esters as their mercuric acetate addition compounds

An Acyl Migration in Acetohalogenoglucosamines1

Paper chromatography of egg lecithins.

Separation and Identification of the Fatty Acids