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Unformatted text preview: verted to more hydrophilic TWEEN® analogues. Although the approach is currently only applied only for sugar esters, it may be transferred on chemically more stable glycosides as well. However, the introduction of ethylene glycol units is leading to a complex product mixture, which limits the application for life science applications, due to excessive biological testing requirements. Instead of a random introduction of ethylene oxide units, we, therefore, aim for a controlled introduction of a limited number of these groups. This can be achieved by forcing the ethylene oxide into a ring. The result is a macrocycle that includes the base glycolipids. The ability of ethylene oxide based macrocycles to complex metal cations might lead to an additional increasing in hydrophilicity. In order to access glycolipids based macrocycles, the 4 - and 6-hydroxyl groups of alkyl glucoside were temporary protected by a cyclic acetal. The remaining hydroxyl groups were hydroxyethylated. The procedure applies the carboxymethylation of th e free hydroxyl groups, followed by reduction of the carboxylic acid derivative. Finally the diol can be coupled with the ditosylate of an oligo-ethylene glycol to provide the desired macrocycles in reasonable yields. The hydroxyethylation of the initial 4,6-protected glycoside increases the synthetic steps compared to a direct reaction with an ethylene oxide ditosylate, but increases the yield of the macrocycle significantly. ORG-O13 SYNTHESIS OF BIOLOGICALLY ACTIVE COUMARIN DERIVATIVES
1 Afsheen Arshad, Hasnah Osman, Chan Kit Lam, Suriyati Muhammad and David S. Larsen
2 1* 2 3 4 School of Chemical Sciences, Universiti Sains Malaysia, 11800 Pulau Pinang, Malaysia School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 Pulau Pinang, Malaysia 3 School of Biological Sciences, Universiti Sains Malaysia, 11800 Pulau Pinang, Malaysia 4 Department of Chemistry, University of Otago, Dunedin, New Zealand E-mail: firstname.lastname@example.org 1 Coumarins constitute an important class of naturally occ...
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This note was uploaded on 02/17/2011 for the course CHEMISTRY 101 taught by Professor Csr during the Spring '11 term at University of Louisville.
- Spring '11