Cellulose sulfoxide-acetic anhydride

Most of the carbonyl groups involve C-3, and reduction of the oxidized dextrans gives modified polysaccharides containing n-allose, n-mannose, and D-galactose residues. Oxidation of 6-O-tritylamylose with methyl sulfoxide-acetic anhydride gives keto groups mainly at C-2. Similar oxidation of cellulose has been described. ... 

Influence of the amount tetra- -butylammonium fluoride (TBAF) trihydrate ou the efficieucy of the acetylation of sisal cellulose with acetic anhydride in dimethyl sulfoxide (DMSO)/TBAF (adapted from [28])... 

Perchloric acid Acetic acid, acetic anhydride, alcohols, antimony compounds, azo pigments, bismuth and its alloys, methanol, carbonaceous materials, carbon tetrachloride, cellulose, dehydrating agents, diethyl ether, glycols and glycolethers, HCl, HI, hypophosphites, ketones, nitric acid, pyridine, steel, sulfoxides, sulfuric acid... 

Cellulose dissolved in suitable solvents, however, can be acetylated in a totally homogeneous manner, and several such methods have been suggested. Treatment in dimethyl sulfoxide (DMSO) with paraformaldehyde gives a soluble methylol derivative that reacts with glacial acetic acid, acetic anhydride, or acetyl chloride to form the acetate (63). The maximum degree of substitution obtained by this method is 2.0 some oxidation also occurs. Similarly, cellulose can be acetylated in solution with dimethylacetamide—paraformaldehyde and dimethylformamide-paraformaldehyde with a potassium acetate catalyst (64) to provide an almost quantitative yield of hydroxymethylceUulose acetate. 

Selective oxidation of amylose at C3 has been achieved with dimethyl sulfoxide/phosphorus pentaoxide [119]. In contrast, the oxidation of unprotected cellulose with dimethyl sulfox-ide/acetic anhydride [120] or dicyclohexylcarbodiimide/dimethyl sulfoxide [121] produced a product containing modified 8-D-glucopyranosyl units - some with a carbonyl function at C2, some with a carbonyl function at C3, and some with carbonyl functions at both C2 and C3[122],... 

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