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Title: Synthesis and studies of stannylated carbohydrate derivatives
Author: Rufino, Helena Clara de Assuncao Rufino
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 1998
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A series of carbohydrate derivatives were prepared and their structural determination was made by NMR spectroscopy. The molecular structures of 1,2-O-isopropylidene-5-O-p-tosyl-α-D-xylofuranose (1) and 1,2-O-isopropylidene-3,5-di-O-p-tosyl-α-D-xylo-furanose (2) was determined by X-ray single-crystal diffraction. All the carbohydrate derivatives were used as precursors for the synthesis of stannylated carbohydrate derivatives. The synthesis of these stannylated carbohydrate derivatives were carried out using two methods: (i) the reaction of triphenylstannyl-lithium with derivatised and protected (or partially protected) carbohydrates and (ii) hydrostannation of alkenyl or allylic substituted carbohydrates using triphenyltin hydride. The solution structures of the triorganotin-carbohydrate derivatives were investigated by 1H, 13C and 119Sn NMR spectroscopy. In solution all the triorganotin-carbohydrate derivatives were shown to contain four-coordinate tin atoms. Reactions of 1,4:3,6-dianhydro-2,5-di-O-p-tosyl-D-glucitol (3) with triphenylstannyl-lithium resulted in the synthesis of (2S,1'R)-(-)-2-[1-hydroxyl-2-(triphenylstannyl)ethyl]-2,5-dihydrofuran (4). Structural elucidation was performed by 1D and 2D NMR experiments as DEPT, HMQC, HMBC, 1H/1H COSY, 1H/1H Long-Range COSY and NOESY NMR experiments. (2R,1'R)-(+)-2-[1-hydroxyl-2-(triphenylstannyl)ethyl]-2,5-dihydrofuran (5) was obtained from reaction of 1,4:3,6-dianhydro-2,5-di-O-p-tosyl-D-mannitol (6) with triphenylstannyl-lithium. Complete assignment of the 119Sn NMR spectra to the different tin atoms of methyl 2,3-di-O-[(dimethylphenylstannyl)methyl]-4,6-O-benzylidene-α-D-glucopyranoside (7) and methyl 2,3-di-O-[(triphenylstannyl)methyl]-4,6-O-benzylidene-α-D-glucopyranoside (8) was obtained from a sequence of single frequency tin decoupling experiments. Complete assignment of the 119Sn NMR spectra for 3-[(triphenylstannyl)propyl] 5-deoxy-2,3-O-isopropylidene-5-C-triphenylstannyl-β-D-ribofuranoside (9) was aided with two dimensional correlation by application of the gradient-heteronuclear multiple quantum coherence method (gs-HMQC) for 1H-119Sn correlation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available