1,3-Nucleophilic addition reactions of thiols and amines with pyranosylnitrile oxides have been employed in the synthesis of <i>C</i>-glycosides. The nitrile oxides were generated by base-induced dehydrochlorination of the corresponding hydroximoyl chlorides 106 and 107. D-Glucose derived hydroximoyl chloride 107 was prepared in four steps from D-glucose and employed in collaborative work toward the synthesis of glucosinolate analogue. Reaction of alkyl and aryl thiols with D-xylose nitrile oxide 151 afforded a series of desulfoisoglucosinolates in 55-76% yields. Reactions of allyl and aryl amines with the D-xylose and D-glucose derived nitrile oxides 151 and 115 under basic conditions afforded the corresponding Z-amidoximes. For example, (<i>Z</i>)-<i>N</i>-benzyl-(2,3,4,6-tetra-<i>O</i>-acetyl-β-D-glucopyranosyl)formamide oxime (137) was prepared from 107 and benzylamine in 88% yield. The addition of amino acid derived nucleophiles was also investigated Reaction of the D-xylose and D-glucose nitrile oxides 115 with L-cysteine derivatives 147 under basic conditions afforded thiohydroximates 148 and 150 in high yield. Reaction of the D-xylose nitrile oxide 151 with glycine, L-leucine and L-phenylalanine esters initially afforded amidoximes 152, 155 and 161. Cyclisation of 152, 155 and 161 to form 1,2,4-oxadiazin-6-ones occurred on exposure to silica or prolonged standing. Employing L-proline benzyl ester as the nucleophile led to the formation of predominantly oxadiazinone 163. Attempts to synthesis pyranosyl-1,2,4-oxathiazin-6-ones were not successful 6-Amino-6-deoxy-1,2,3,4-di<i>-O-</i>isopropylidene-α-D-galactopyranose hydrochloride was prepared from D-galactose in 4 steps, and reaction with D-xylose and D-glucose derived nitrile oxides 151 and 115 afforded (1→6) amidoxime linked pseudo-disaccharides 178 (81%) and 181 (75%) D-Xylose and D-glucose amines 182 and 183 were prepared from the parent aldoses in 5 steps. Reaction of these amines with D-xylose and D-glucose nitrile oxides 151 and 115 yielded a series of (1→1) amidoxime linked pseudo-disaccharides (41-49% yields).
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:662052 |
| Date | January 2005 |
| Creators | Smellie, Iain Archie Sneddon |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/14433 |
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