Allose 6-deoxy-2,3-di-0-methyl

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. 

This interesting transformation from a readily available 6-deoxyhexose forms the basis for the synthesis231 of 6-deoxy-2,3-di-0-methyl-D-allose (mycinose),168 one of the carbohydrate moieties of the antibiotic chalco-mycin. The synthesis merely involves the protection of the C-5 hydroxyl group in (41) by benzylation, followed by partial hydrolysis with acid, methylation of the product at the C-2 and C-3 hydroxyl groups, and debenzylation. 

Single-crystal X-ray analysis has established that the novel macrolide antibiotic isolated from S. chryseus has the structure (11), containing mycarose, 4,6-dideoxy-D-eryt/zro-hexos-3-ulose, and 6-deoxy-2,3-di-0-methyl-L-allose as separate sugar units. Similarly X-ray analysis has shown that rosaramicin obtained from Micromonospora rosaria contains desosamine 3-linked to a macrolide ring. Mycinamycins, a new family of basic 16-membered macrolide antibiotics from Micromonospora sp. A-11725, also contain desosamine along... 

A combination of chemical and spectroscopic methods has been elegantly used to establish the complete structures of aldgamycins E and F (338), two closely related macrolide antibiotics isolated from Streptomyces lavendulae. Each antibiotic contains mycinose (6-deoxy-2,3-di-0-methyl-D-allose) and aldgarose (see p. 100) as component sugars. 

L-mycarose, 2,6-dideoxy-3-C-methyl-L-ribohexose L-cladinose, 2,6-dideoxy-3-0-methyl-3-C-methyl-L-ribohexose L-arcanose, 2,6-dideoxy-3-O-methyl-3-C-methyl-L-xylohexose L-oleandrose, 2,6-dideoxy-3-0-methyl-L-arabohexose D-lankavose, 4,6-dideoxy 3 -0-methyl-D-xylohexose D-mycinose, 6-deoxy-2,3-di-0-methyl-D-allose D-mycaminose, 3,6-dideoxy-3-dimethylamino-D-glucose D-desosamine, 3,4,6"trideoxy-3-dimethylamino-D-xylohexose forosamine, 2,3,4,6-tetradeoxy-4-dimethylaminohexose... 

Deoxyallofuranosyl bromide p-D-ybrm Tris(4-nitrobenzoyl), D-33 6-Deoxyallose D-/orm, D-34 6-Deoxy-2,3-di-0-methylallose r>-/orm, D-57 6-Deoxy-2-0-methylallose, SCI, D-34 6-Deoxy-3-6>-methyl-D-allose, D-34 l,4-Di-0-acetyl-6-deoxy-2,3-di-0-metl l-D-allose, D-57... 

Recent applications of this reaction include the reduction of methyl 3-0-benzyl-2-O-methyl-6-O-p-tolylsulfonyl-a-D-allopyranoside, leading to the synthesis of 6-deoxy-2-0-methyl-D-allose, and the reduction of methyl 3-0-methyl-2,6-di-0-p-tolylsulfonyl-a-D-allopyrano-side as a step in the synthesis of 6-deoxy-3-0-methyl-D-allose. The last-named compound was also synthesized, in lower yield (because of competing side-reactions), starting from methyl 3-0-methyl-2,4,6-tri-0-p-tolylsulfonyl-a-D-allopyranoside. 

A number of 6-deoxyhexoses also are widespread in plants, but these compounds are especially common in cardiac glycosides (Courtois and Percheron, 1970). These sugars are formed from the corresponding hydroxylated monosaccharides (Luckner, 1990). Among the 6-deoxyhexoses are L-acofriose (6-deoxy-3-0-methyl-L-mannose) (18), l-acovenose (6-deoxy-3-6>-methyl-L-talose) (19), o-allometh-ylose (6-deoxy-D-allose) (20), L-altromethylose (6-deoxy-L-altrose) (21), D-antiarose (6-deoxy-o-gulose) (22), D-boivi-nose (2,6-dideoxy-D-xy/o-hexose) (17), D-cymarose (2,6-di-... 

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