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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Studies of triorganotin-pentofuranoses

Burnett, Lynne A. January 1995 (has links)
A series of novel triphenylstannyl-C, (triphenylstannyl)methyl- O- and (tributylstannyl)methyl-O- substituted pentofuranose compounds have been synthesised. Two methods were employed: (i) the reaction of triphenyltinlithium with derivatised and protected (or partially protected) carbohydrates, and (ii) the reactions of carbohydrate alkoxides with (iodomethyl)triphenyltin and (iodomethyl)tributylin. The solution structures of the triorganotin-carbohydrate compounds were investigated by 1H, 13C and 119Sn NMR spectroscopy. In solution all of the triorganotin-carbohydrates were shown to contain four-co-ordinate tin atoms. The solid-state structures were investigated by a combination of solid-state NMR spectroscopy and single-crystal X-ray diffraction. There were no major conformational changes between the two phases for any of the compounds. The molecular structures of methyl 5-deoxy-2,3- O-isopropylidine-5-triphenylstannyl-beta-D-ribofuranoside and 5-deoxy-1,1- O-isopropylidine-5-triphenylstannyl-alpha-D-xylofuranose were determined. Two different molecular conformations were identified for the former compound, and hydrogen-bonding between adjacent molecules was shown to be present in the latter case. The reactions of the triorganotin-carbohydrate compounds with iodine and bromine were studied. The results indicated that the rate of cleavage of butyl-tin bonds was much slower than the cleavage of phenyl-tin bonds. The reactivity of the tin-phenyl bond was found to depend greatly on the structure of the carbohydrate ligand. Evidence of increased co-ordination in solution was found for the mono-halo derivatives of methyl 5-deoxy-2,3-O-isopropylidine-5-triphenylstannyl-beta-D-ribofuranoside and 5-deoxy-1,2-O-isopropylidine-5-triphenylstannyl-alpha-D-xylofuranose. The molecular structures of 5-deoxy-5-iododiphenylstannyl-1,2-O-isopropylidine-alpha-D-xylofuranose and 5-deoxy-5-diiododiphenylstannyl-1,2-O-isopropylidene-alpha-D-xylofuranose were determined. In the solid-state the geometry about the tin atoms was found to be distorted trigonal bipyramidal.

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