A-Cellobiose

The preparation of a-cellobiose octaacetate by the acetolysis of cellulose was discovered by Franchimont, and the process has been studied carefully by a number of other investi-... 

Hepta-Oacetyl-6 -Otosyl-a-cellobiose or 2,3,4-tri-0-acetyl-6-Otosyl-p-D-glucopyranosyl-(1 ->4)-1,2,3,6-tetra-Oacetyl-a-... 

Figure 2.3 The molecular structure of /3-D-glucopyranose (a), cellobiose (b) and the glucopyranose backbone of cellulose (c), and (d) a schematic of the linear arrangement of the glucopyranose units.

In 1963, a series of systematic studies was begun on the reaction of fully acylated disaccharides (acetates and benzoates) with methanolic or aqueous solutions of ammonia at room temperature. Octa-O-acetyl-a-cellobiose in 16% methanolic ammonia afforded44 1,1-bis-(acetamido)-l-deoxycellobiitol (45) and N-acetyl-a-cellobiosylamine (46), which is the anomer of the cellobiosylamine previously described by Zechmeister and Toth41 and Micheel and coworkers.43... 

The crystalline structure of cellulose has been characterized by X-ray diffraction analysis and by methods based on the absorption of polarized infrared radiation. The unit cell of native cellulose (cellulose I) consists of four glucose residues (Figs. 3-6 and 3-7). In the chain direction (c), the repeating unit is a cellobiose residue (1.03 nm), and every glucose residue is accordingly displaced 180° with respect to its neighbors, giving cellulose a... 

Fig. 45. Schematic representation of the it -a electron conjugate system in a cellobiose unit291...

Fie. 9.1a, b. Inter-residue intramolecular hydrogen bonding in a cellobiose (CELLOB02), b me-thyl-/ -maltopyranoside monohydrate (MALTOS11) (one is direct, one is through a water molecule)... 

Kitaoka, M, Ogawa, S, Taniguchi, H, A cellobiose phosphorylase from cellvibrio-gilvus recognizes only the beta-D-form of 5a-carba-glucopyranose, Carbohydr. Res., 247, 355-359, 1993. 

Lindgren, A., Stoica, L, Ruzgas, T., Ciucu, A., and Gorton, L. (1999) Development of a cellobiose dehydrogenase modified electrode for amperometric detection of diphenols. 

For several years a mechanism involving simultaneous transfer of two glucose residues (I. M Saxena, R. M. Brown, M. Fevre, R. A. Geremia and B. Henrissat, J. Bacterial. 1995, 177, 1419) to form a cellobiose unit was favoured, but can now be discounted because of the absence of more than one nucleotide sugar binding domain in cellulose synthases. 

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