83 デストマイシンAの合成研究

概要

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Destomycins produced by a strain of Streptomyces rimofaciens are aminoglycoside antibiotics of the orthosomycin family having antelmintic activity. The absolute configuration of the orthoester interlinkage of destomycin A {3-amino-1-methylamino-5-O-[2,3-O-(6-amino-L-glycero-D-galacto-heptopyranosylidene)-β-D-talopyranosyl]-1D-1,2,3-trideoxy-myo-inositol} was determined to be (R) by the X-ray analysis of the corresponding tri-N-ethoxycarbonyl-octa-O-acetyl derivative. The 6-amino-heptonic acid called destomic acid and its 6-epimer, and 4-epidestonic acid found in destomycin B and its 6-epimer were synthesized from 1,2: 3,4-di-O-isopropylidene-α-D-dialdogalactopyranose and methyl 2,3,4-tri-O-benzyl-α-D-dialdoglucopyranoside, respectively, by the successive cyano-mesylation, azylidine-ring formation, the ring-opening, oxidation into the corresponding aldonic acid, and the deprotection. For the formation of the characteristic orthoester interlinkage, a new method by the reaction of 2,3,4,6-tetra-O-benzyl-D-glucono-1,5-lactone with trimethylsilylated diols in the presence of trimethylsilyl triflate was developed, in addition to the reaction of the lactone with epoxide or diols directly. The stereochemistry of the glucosyliden acetals thus obtained were discussed, and the half synthesis of destomycin A by the use of the new method was examined.
天然有機化合物討論会の論文
1981-09-10