D-mycinose

A few neutral 16-membered macroHdes have been isolated. The stmcture of chalcomycin (54, R = CH3, R = OH), produced by S. bikiniensis was estabhshed as a 16-membered lactone having two neutral sugars, D-chalcose (7) and D-mycinose (9, R = R = OH3) (293—295). Its aglycone resembles that... 

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. 

Desosamine (154), in which the 3-O-methyl group of chalcose is replaced by a dimethylamino group, is found in the macrolide mycinamicin I (158).230,233 Genes for the synthesis of the two deoxy sugars of chalcomycin, D-chalcose, and D-mycinose were characterized in a gene cluster from S. bikiniensis.230... 

Matsumoto, T, Maeta, H, Suzuki, K, Tsuchihashi, G, New glycosidation reaction 1. Combinational use of Cp2ZrCl2-AgC104 for activation of glycosyl fluorides and application to highly 3-selective glycosidation of D-mycinose, Tetrahedron Lett., 29, 3567-3570, 1988. 

Tylosin contains a 16-membered lactone to which three deoxysugar moieties are attached. A disaccharide D-mycaminosyl-D-mycarose is linked at C5 and a D-mycinose at C23. Several genes have been cloned that encode deoxysugar biosynthetic enzymes most of them are involved in dTDP-D-mycaminose biosynthesis [48,49]. TylAl and TylA2 correspond to the dTDP-o-glucose synthase and dTDP-4,6-dehydratase, respectively. A putative isomerase not yet identified acts on dTDP-4-keto-6-deoxy-D-glucose, and then aminotransferase (TyiB) and C-methyltransferase (TylMl) to generate the final dTDP-D-mycaminose. 

Ortnycaminose 1 t-myoarose 1 0 O—D-mycinose tylosin angolamycin relomycin 0.4-12.5 >100... 

A new component of the algamycin complex has been identified, algamycin G (containing D-mycinose and the branched-chain sugar... 

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... 

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