Allose 2,6-dideoxy

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... 

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. 

Alternative routes to compounds of this class involve the treatment of 5,6-anhydrides with methyllithium, and the application of the Chugaev reaction. Thus, 3-0-benzyl-5,6-dideoxy-l,2-0-isopropylidene-a-n-a 2/Zo-hex-5-enose (113, R = CHjPh) has been obtained from both 5,6-anhydro-3-0-benzyl-l,2-0-isopropylidene-a-D-glucofuranose and the related -L-idose derivative, and has been identified with the product prepared from 3-0-benzyl- 1,2-0-isopropylidene-5,6-di-0-p-tolysulfonyl-a-D-glucofuranose. Methyl 5,6-dideoxy-2,3-0-isopropylidene-/3-D-n6o-hex-5-enofuranoside (114) was obtained from the corresponding n-allose 5-methylxanthate derivative. 

Racemic 3-amino-sugars have been synthesized through hetero-Diels-Alder reactions of enaminones, Thus the major adduct from enamlnone (M6) and ethyl vinyl ether was converted to the M-deoxy-rlstosamlnide (M ) (Scheme 19). Racemic 5,6-dideoxy-5-amlno-allose derivatives such as (M8) have been constructed from the hetero-Dlels-Alder adducts of diene (M9) with acylnitroso... 

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-... 

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... 

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