RESUMO
[reaction: see text]. The synthesis of D-lyxo-hexos-5-ulose (5-ketomannose, 1,5-dicarbonyl sugar), a synthetic precursor to the glycoprocessing inhibitor deoxymannojirimycin, was carried out by an in situ epoxidation and hydrolysis of a trimethylsilyl-protected 6-deoxyhex-5-enopyranoside followed by facile removal of the protecting groups. A novel nine-step synthesis of deoxymannojirimycin has also been achieved from methyl alpha-D-mannopyranoside; this involved methanolysis of epoxides derived from an acetylated 1-azido-6-deoxyhex-5-enopyranoside followed by deprotection and catalytic hydrogenation.
Assuntos
1-Desoxinojirimicina/síntese química , Inibidores Enzimáticos/síntese química , Glicosídeo Hidrolases/antagonistas & inibidores , Manose/síntese química , Antibacterianos/síntese química , Antivirais/síntese química , Química Farmacêutica , Compostos de Epóxi/química , Manose/análogos & derivados , Metilmanosídeos/químicaRESUMO
[reaction: see text] Epoxides derived from 2,3, 4-tri-O-protected-6-deoxyhex-5-enopyranosides are hydrolyzed in situ to ultimately give novel protected-D-hexos-5-ulose derivatives (sugar 1,5-dicarbonyls, 5-ketohexoses) in moderate to high yields. The products adopt a bicyclic structure (1,6-anhydropyranos-5-ulose) in solution with the pyranose ring in (4)C(1) conformation. The methodology has been used to prepare D-xylo-hexos-5-ulose (5-ketoglucose), a synthetic precursor to 1-deoxynojirimycin and a possible intermediate in the biosynthesis of inositols.
Assuntos
Desoxiglucose/análogos & derivados , Desoxiglucose/química , Compostos de Epóxi/química , Hexoses/química , Compostos de Epóxi/síntese química , HidróliseRESUMO
[reaction: see text]. The Ugi reaction has been used to prepare divalent galactose derivatives. NMR analysis shows that a divalent neoglycoconjugate, where the glycopeptides are bridged by a terephthaloyl group, is an 83:17 mixture of two conformers; the amide groups of the major isomer have E-anti conformations. The spatial relationship and the relative orientation of the sugars are restricted, which may have consequences for the recognition of this and related structures in biological systems.
Assuntos
Glicoconjugados/síntese química , Configuração de Carboidratos , Glicoconjugados/química , Espectroscopia de Ressonância MagnéticaRESUMO
The synthesis of 4,6-O-benzylidene-beta-D-erythro-2-3-dideoxyhex-2-enopyranosides and their osmium and ruthenium catalysed dihydroxylation reactions have been investigated. These reactions have been shown, for a range of monosaccharides and a disaccharide, to proceed stereospecifically to give beta-D-allopyranosides in moderate to excellent yield.
Assuntos
Dissacarídeos/síntese química , Glicosídeos/síntese química , Compostos Policíclicos/síntese química , Catálise , Hidroxilação , Osmio/química , Rutênio/química , EstereoisomerismoRESUMO
The design and synthesis of a series of analogues of sialyl Lewis(x)(1) which incorporate conformationally rigid tetralin and naphthalene ring systems(2-4) has led to novel compounds which have similar potency to 1 as inhibitors of cell adhesion.