Role of hydroxyl group on the mesomorphism of alkyl glycosides:synthesis and thermal behavior of alkyl 6-deoxy-beta-D-glucopyranosides

Singh, Madan Kumar and Jayaraman, Narayanaswamy and Rao, Shankar DS and Prasad, Krishna S (2010) Role of hydroxyl group on the mesomorphism of alkyl glycosides:synthesis and thermal behavior of alkyl 6-deoxy-beta-D-glucopyranosides. In: Chemistry and Physics of Lipids, 163 (6). pp. 580-585.

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Abstract

A homologous series of alkyl 6-deoxy-beta-D-glucopyranoside amphiphiles was prepared,in an effort to identify the role of hydroxyl group in the mesomorphic behavior of alkyl glycosides. Synthesis was performed by a chlorination of the sugar moiety in alkyl-beta-D-glucopyranosides with methylsulfonyl chloride in DMF, followed by a metal mediated dehalogenation to secure alkyl 6-deoxy-beta-D-glucopyranosides, wherein the alkyl chain length varied from C-9 to C-16. The mesomorphic behavior of these 6-deoxy alkyl glycosides was assessed using polarizing optical microscopy, differential scanning calorimetry and X-ray diffraction method. Whereas the lower homologues exhibited a monotropic SmA phase till sub-ambient temperatures, the higher homologues formed a plastic phase. A partial interdigitized bilaye structure of SmA phase is inferred from experimental d-spacing and computationally derived lengths of the molecules. The results were compared with those of normal alkyl glucopyranosides, retained with hydroxyl groups at C-2-C-6 carbons, and alkyl 2-deoxy-glucopyranosides, devoid of a hydroxyl group at C-2 and the comparison showed important differences in the mesomorphic behavior.(C)2010 Elsevier Ireland Ltd. All rights reserved.

Item Type:	Journal Article
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	6-Deoxy glycosides;Glycolipids;Liquid crystals;Smectic A phase;Plastic phase
Department/Centre:	Division of Chemical Sciences > Organic Chemistry
Date Deposited:	09 Aug 2010 05:59
Last Modified:	19 Sep 2010 06:13
URI:	http://eprints.iisc.ernet.in/id/eprint/31221

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