Amylose 3,6-anhydro

Anhydro-p-D-mannopyranose 8,70,90,140,262,278) Aus Amylose kann pyrolytisch ein Pyrodextrin erhalten werden partielle saure Hydrolyse fiihrt zu einer Reihe von Disacchariden, neben denen auch Laevoglucosan gefunden wurde 22,249,254)... 

Ball, D. H., Cimecioglu, A. L., Kaplan, D. L., and Huang, S. H. (1994). Site-selective modification of polysaccharides under homogeneous conditions. New anhydro and cationic polymers derived from amylose and pullulan. 208th Annual Meeting, Am. Chem. Soc., Div. Cellulose, Paper and Textiles, August 21-26, Washington, DC. 

Amylose, as well as amylopectin, pyrolyzed at a pressure of 2.00 to 2.66 kPa at 420 yields four nonvolatile compounds, the yield of which, given in % (in parentheses), does not depend much on the source pyrolyzed. These compounds are l,6-anhydro-)9-D>glucopyranose (28.8 and 24.7), 1,6-anhy-dro-)3-D>glucofuranose (2.0 and 2.1), 1,4 3,6 dianhydro-oc-D-glucopyranose (1.2 and 1.6), and 5-(hydroxymethyl)-2-furaldehyde (0.4 and 0.4) from both pyrolyzed sources. ... 

Anhydrides of pyranoses and furanoses are usually formed by intramolecular displacements of 6-sulfonyloxy groups.370-394 These replacements often occur very readily (for example, during methyla-tion,24 and during attempted solvolysis of 3-0-acetyl-l,2-0-isopropyli-dene-5,6-di-0-p-tolylsulfonyl-a-D-glucofuranose280). 3,6-Anhydro rings have been introduced into amylose chains,68-395 and 2-amino-3,6-anhydro-2-deoxy-D-mannose derivatives have been prepared.396... 

Recently various chemical modifications and derivatizations of polysaccharides have been developed to meet new needs. However, introduction of 3,6-anhydro-linkages to the polysaccharides appear to be limited to 3,6-anhydro-amylose (14). Our interest has been drawn to the introduction of 3,6-anhydro-linkages into a-(1 4)-linked D-glucose units of elsinan, whereby some alteration of the physical properties would be expected. 

Reductive cleavage of glycosldic bonds of permethylated methyl a- and B-D-glucopyranoside, cyclohexa-amylose and cellulose has been effected with triethylsllyl deuteride and boron trifluorlde or, better, with trlmethylsllyl trlflate as catalyst. 1-Deuter-ated 1,5-anhydro-D-glucltols were obtained with an a 6 ratio of... 

Products from the pyrolysis of cellulose in the absence of a catalyst were found to be mainly derivatives of 1,6-anhydro-D-glucoseand other, unsaturated, products. One product, formed in 1.4% yield, was found to be 1,5-anhydro-4-deoxy-D- /yc ro-hex-l-en-3-ulose. This product was also formed during the pyrolysis of amylose, amylopectin, and laminarin. A further product from cellulose, probably formed as an oxidation product, was 3,5-dihydroxy-2-methyl-4/f-pyran-4-one. Sixty-three compounds were detected in the condensate of smoke produced by pyrolysis of cellulose. These compounds included furans, cyclic ketones, lactones, benzene derivatives, aliphatic ketones, and aldehydes. One of the major products was 2-hydroxy-3-methyl-cyclopenten-l-one. 

Amphoteric Surfactants tensioactifs amphot res Amylases amylases Amyloiysis amylolyse Amylomaize Starches amidon amylosique du mat s, amyloamidon du mtds Amylopectin amylopectine Amylose amylose Amylum amylum, f cule Anhydro Glucose Unit unit6 d anhydro-glucose (UAG)... 

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