Disaccharides, pseudo

Purification by flash chromatography yielded the pseudo-disaccharide as a glass... 

The first two steps providing myo-inositol are the same as in the STR pathway and are already described there (see paragraph on STRs). The possibility that a hydrolase, KasE, could be a possible myo-inositohnonophosphate monophosphatase is provided by the expression of the respective gene in the -cluster. The myo-inositol is assumed to be directly incorporated into the first pseudo-disaccharidic intermediate. 

Because 6-deoxyhex-5-enopyranose derivatives can be readily converted into 2-deoxyinososes,91 5-bromides (for example, 164) give useful access to such carbocyclic compounds.92 In this way, octa-0-acetyl-/ -maltose was converted by treatment with zinc-acetic acid into the 5-ene by way of the corresponding 5-bromide 30 and thence into the pseudo-disaccharide compound (169) which is related to components of members of the aminoglycoside antibiotic series.36... 

The conformation of the synthetic putative ligatin receptor has been determined by its phosphorus carbon and phosphorus hydrogen coupling constants [234]. The pseudo-saccharide bond to phosphorus adopts a normal conformation and obeys the exo anomeric effect. The total shape of this pseudo disaccharide is a stretched out conformation. 

A. Le Chevalier, R. Pierre, S. Chambert, A. Doutheau, and Y. Queneau, Preparation of amide-linked pseudo-disaccharides by the carboxymethylglycoside lactone (CMGL) strategy, Tetrahedron Lett., 47 (2006) 2431-2434. 

From these results, it may be concluded that the pseudo-disaccharide 44 is the first intermediate in the assembling of the three components of dihydrostreptomycin. The fact that no transfer-product was observed with streptidine is in agreement with the conclusions from a number of studies in which the importance of phosphorylated intermediates in the biosynthesis of streptomycin was established.36,64,65... 

Pearce, A J, Sollogoub, M, Mallet, J M, Sinay, P, Direct synthesis of pseudo-disaccharides by rearrangement of unsaturated disaccharides, Eur. J. Org. Chem., 9, 2103-2117, 1999. 

Pelyvas, I. F., Madi-Puskas, M., Toth, Z. G., Varga, Z., Hornyak, M., Batta, G., Szlaricskai, F. Synthesis of new pseudo-disaccharide amino glycoside antibiotics from carbohydrates. J. Antibiot. 1995, 48, 683-695. 

S. Ogawa and H. Sugizaki, Synthesis of a pseudo-disaccharide derivative having d-manno configuration, an acarviosin analog, Chem. Lett., 17 (1986) 1977-1980. 

DOrner and Westermann [149] reported the preparation of the pseudodisaccharide 143 with a triazole tether (Scheme 37) as a prototype for the synthesis of carbohydrate-containing macrocycles, through a Huisgen-catalysed reaction and ring-closing methathesis as the key steps. Standard conditions were used, Cu(OAc)2 and sodium ascorbate as the Cu(I) source and a mixture of water and f-BuOH as solvent, for the conversion of protected glucopyra-nosyl azide 141 into pseudo-disaccharide 143 by using dialkyne 142 in a 77% yield. 

New antibiotics reported this year have included several groups of closely related pseudo disaccharides fortimicin C, a carbamoyl derivative of fortimicin A (1), fortimicin D, the 6 -demethylated analogue of fortimicin A, and fortimicin KE, the d -demethylated derivative of fortimicin B (2), have been isolated from the culture broth of Micromonospora olivoasterospora, which also yields fortimicin A and and sporaricin A (3, = NHjCHaCO-) and sporaricin B (3, = H)... 

Amidine and Guanidine Derivatives - The A/-alkyl-D- ucosamidinium salts 63 have been synthesized by condensation of nojirimycin with the appropriate amine followed by oxidation with iodine. Amidine-linked pseudo-disaccharide 66 has been synthesized by reaction of the thionolactam 64 with the 6-amino-sugar 65 (Scheme 16), and a (l- 4)-linked analogue has been obtained similarly. ... 

V,A -Diacetylchitobiose has been converted into the pseudo disaccharide, P-D-GlcNAcp-(l- 4)-2-acetamido-l,2,5-trideoxy-l,5-imino-D-glucitol by way of intermediate 62. This was oxidized and reduced to give the 5-OH epimer of 62, converted to a mesylate, reduced to the 1-amino compound (which effects cyclization) with displacement of mesic acid and finally de-benzyl-ated. ... 

The N-linked pseudo-disaccharide 132 has been prepared from imino-D-altro-hexitol 45 (Section 1.3.1) and this compound was found to be a potent inhibitor of P-galactosidase Ki 3.3 pm). ... 

Syntheses have been reported for the pseudo-disaccharides (44)... 

Deamination of N-deacetylated glycosamino-glycans followed by sodium borodeuteride reduction led to pseudo-disaccharides of 2,5-anhydro-D-mannitol or -D-talitol (from D-glucosamine and D-galact-osamine residues respectively) with attached glucuronic acid,... 

Anhydromaltose has been converted to the pseudo-disaccharides (25) containing 3-amino-3-deoxy-epz-inositol or 1-amino-l-deoxy-l-L-myo-inositol via the 6-deoxy-6-nitromaltose derivative (26). The branched-chain unsaturated 6-nitro-sugar (27), prepared conventionally from D-glucose, yielded isomeric dithianyl adducts which were similarly cyclized to give the nitro-cyclitols (28) and (29), of interest as potential intermediates for the synthesis of tetrodo-... 

Paulsen s group has transformed the protected streptosyl chloride (or bromide) (521 RS = Ph,H) into dihydrostreptosylstreptidine (522) and related pseudo-disaccharides. ° ° The 2,3-0-benzylidene derivatives (521 R R = Ph,H) yielded a-linked glycosides of L-streptose preferentially, whereas the 2,3-carbonates (521 R R = O) gave / -linked glycosides e.g. with cyclohexanol and l,2,3,4-tetra-0-acetyl-)5-D-glucopyranose). ° This work culminated in the synthesis of D-streptobiosamine (523) and its L-enantiomer (a disaccharide unit of streptomycin) by a route that involved condensation of methyl a-o(or L)-strepto-side 3 -(trimethylene dithioacetal) with the nitrosyl chloride adduct of 3,4,6-tri-O-acetyl-D-(or L)-glucal. ... 

A series of pseudo-disaccharides has been prepared by condensing appropriate deoxy-inositol and glycal derivatives to give a-linked 3 -deoxy-cyclitol glycosides, e.g. (29) which were further transformed to amino-deoxy-cyclitol glycosides, e.g. (30). ... 

Reviews have appeared on the synthesis of aminoglycoside antibiotics, and on the formation of new aminocyclitol antibiotics by mutants of amino-cyclitol-producing organisms fed with aminocyclohexanol or related subunits. The structures of eight minor components of the nebramycin complex elaborated by Streptomyces tenebrarius have been elucidated besides neamine and related pseudo-disaccharides, the new components are pseudo-trisaccharides related to kanamycin B, and the 3 -hydroxy analogue of the principal component of the complex, apramycin (see Vol. 10, p. 130). ... 

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