D-Allose

D-Allose D-Altrose D-Glucose -Mannose D-Gulose D-ldose -Galactose D-Talose... 

Syntheses of 6-Deoxy-2 and 3-0-Methyl-D-allose and Some 6-DeoxyhexopyranosidePhenyl-boronates... 

An isomeric sugar, D-javose, is a constituent of two cardenolide glycosides (strophanthojavoside and antiarojavoside) found (42) in the seeds of Antiaris toxicaria Lesch. Degradative studies indicated (42) that javose had the structure 6-deoxy-2-0-methyl-D-allose (17) and this assignment was confirmed by two stereospecific syntheses. 

Figure 2. Synthesis of 6-deoxy-2-0-methyl-D-allose (javose).

Syntheses of 6-Deoxy-2- and 3-O-methyl-D-allose and Some 6-Deoxyhexopyranoside Phenyl-boronates," J. S. Brimacombe, A. Husain, F. Hunedy, and M. Stacey, Adv. Chem. Sen, No 74 ( Deoxy-sugars") (1968) 56 - 69. 

Deoxy-p-D-xy/o-hexopyranose 2-Deoxy-D-ribo-hexose not 2-deoxy-D-allose not 4-deoxy-p-D-galactopyranose... 

Cyclohexyl-4 deoxy-4-(hydroxymethyl)-D-allose [oxygen (in CH2OH) has priority over carbon (in cyclohexyl) at C-4] or (4fl)-4-cyclohexyl-4-deoxy-4-(hydroxymethyl)-D-ribo-hexose... 

Mycarose Mycinose Neuraminic acid (Neu) 2,6-D ideoxy-3- C-methy I-l- ribo- hexose 6-Deoxy-2,3-di-Omethyl-D-allose 5-Amino-3,5-dideoxy-D-g/ycero-D-ga/acfo-non-2-ulosonic acid... 

Six of the 18 aldohexoses, namely, D-glucose, d- and L-mannose, D-galac-tose, D-allose, and L-altrose have been found in bacterial polysaccharides. 

D-Allose and L-altrose are components of the extracellular polysaccharides elaborated by Pseudomonas viscogena and Butyrovibrio fibrisol-vens, respectively. 

P2j Z = 2 D = 1.17 R = 0.080 for 3,888 intensities. This is aconfigu-rational analysis of the macrolide antibiotic 23672RP from Streptomyces chryeus. All three sugar residues are pyranoid the conformation of the a-ketose is CX, with Q = 56 pm, 0 = 9° that of the / -D-mycinose (6-deoxy-2,3-di-0-methyl-D-allose) is 4Clt with Q = 59 pm, 0 = 6° and that of the / -L-mycarose (2,6-dideoxy-3-C-methyl-L-riho-hexose) is 1C4, with Q = 53 pm, 0= 177°. The O-5-C-l-O-l-C glycosidic torsion-angles are —71, —87, —83°. The atomic coordinates reported in the paper refer to the opposite enantiomer. 

C35H4206S4 4,5,6-Tri-0-benzoyl-2,3,-di-S-ethyl-2,3-dithio-D-allose diethyl TBETHA 38 482... 

Intramolecular cycloadditions of chiral nitrones provide a useful tool for the preparation of bioactive heterocyclic compounds.63 Shing et al. demonstrated that 1,3-dipolar cycloaddition of nitrones derived from 3-0-allyl-hexoses is dependent only on the relative configuration at C-2,3, as shown in Scheme 8.16. Thus 3-0-allyl-D-glucose and -D-altrose (both with threo-configuration at C-2,3) produce oxepanes selectively, whereas 3-O-allyl-D-allose and -D-man-nose (both with erythro-configuration at C-2,3) give tetrahydropyranes selectively.80... 

The identities of the individual sugars were established by acid hydrolysis of a portion of the sample followed by paper chromatography and comparison with authentic samples. It was interesting to note that one of the sugars was the rarely encountered (S-D-allose that has only been found in a few saponins. Regrettably, only scant details were reported on the acquisition conditions used for the 1,1-ADEQUATE spectrum. 

Allitol was characterized by its melting point, 149-150°, elementary analysis, and by the formation of a dibenzylidene derivative, which, after recrystallization from alcohol, melted at 249-250° on the Maquenne block. Later, Steiger and Reichstein7 repeated this synthesis of allitol and demonstrated the identity of the product with that obtained by the reduction of D-allose. 

HC104-Si02 selectively cleaves terminal isopropylidene groups of the diisopropyl-idene derivatives of D-glucose, D-allose, and methyl D-gluconate in high yield. 

The potentialities of this method are such that, with the proper choice of hexofuranose derivative, access can be gained to 2,5-anhydroaldoses in which the side chains have the cis orientation, as would be required for further elaboration into C-nucleosides. Matsui and coworkers62 reported the synthesis of modified C-nucleosides by acidic treatment of 3-0-benzyl-l,2-0-isopropylidene-5,6-di-0-(methylsulfonyl)-/3-L-talofuranose (60), to give 2,5-anhydro-3-0-benzyl-6-0-(methylsulfonyl)-aidehydo-D-allose dimethyl acetal (61). 

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