Synthesis of Four Carboxymethyl Ethers of Glucose

Abstract

The 2-, 3-, and 6-0-carbosymethyl-D-glucoses and the 2,3-di-0-carboxymethyl-D-glucose have been synthesized. A solvent system was found which gave complete paper chromatographic separation of these derivatives as well as of those obtained upon hydrolysis of a carboxymethylcellulose.The physical and chemical properties of partially substituted cellulose derivatives cannot be explained only in terms of molecular weight, polymolecularity, and degree of substitution, the distribution of the substituents along the chain molecules of cellulose also having to be considered. Various approaches in such distribution studies have been used, the most direct of which involves quantitative paper chromatography. Brownell (3) appears to have come the closest t o a successful application of such a method in his work on hydroxyethylcellulose. However, in this study, as well as in similar work on methylcellulose (1, 8, l l ) , most of the isomeric mono-and di-substituted derivatives of glucose could not be separated.Previous investigations on carboxymethylcellulose (6, 12, 15, 16) have indicated the desirability of a more direct approach and this study was undertaken to develop the quantitative paper chromatographic technique for this purpose. Three stages had to be considered in this connection, namely hydrolysis of the carboxyrnethylcellulose, separation and identification of the various carboxymethylated glucoses in the hydrolyzate, and the quantitative determination of these glucose derivatives.The hydrolysis of carboxymethylcellulose and the stability of the carboxymethyl group to the coilditions of acid hydrolysis have been previously investigated (15). For separation and identification of the seven possible carboxymethyl derivatives of glucose which conceivably could be formed by hydrolysis of a partially substituted carboxymethylcellulose, it was necessary to have these seven compounds available. The present study deals with the synthesis and separation of the 2-, 3-, and 6-0-carboxymethyl-D-glucoses and the 2,3-di-0-carboxymethyl-D-glucose. RESULTS AND DISCUSSIONThe general procedure used for introducing the carboxymethyl groups in the desired positions was t o allow methyl bromoacetate t o react with the sodio compound, prepared by the reaction of metallic sodium with a glucose derivative having the appropriate hydroxyl groups unsubstituted. For the preparation of the sodio derivative, advantage was taken of the greater chemical reactivity of sodium dispersions (2). Such dispersions consist of a stable sus-'Manz~script

Distribution of substituent groups in O-(2-aminoethyl)cellulose

“…This derivative was prepared by lithium alun~inium hydride reduction of 4.0 g of chromatographically pure 3-O-carbon1ethoxymethyl-1,2;5,6-di-O-isopropylidenea-D-glucofuranose by the procedure of Shyluk and Timell (9). The isopropylidene groups were removed by hydrolysis.…”

Enzymatic degradation of carboxymethylcellulose and other cellulose derivatives

“…Isolation of Carboxymethyl Glucoses Carboxymethyl cellulose of DS 0.7 (1 g) was mixed with 5 ml of 72% sulfuric acid, stirred at 40"C, for 45 min, diluted to 350 ml and autoclavedfor 1 hour [23]. The mixture was neutralized with barium carbonate, filtered through Celite, and treated with Amberlite IR-120 (H') resin.…”