67 ヌクレオシド抗生物質ダピラミシン及びミハラマイシンの構造

概要

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Dapiramicin A and miharamycins (A and B) are novel nucleoside antibiotics, both of which are effective in the treatment of sheath blight disease and rice blast disease, respectively in the green house test. The sugar moiety of dapiramicin A (1) has been determined to be 6-deoxy-4-O-(4-O-methyl-β-D-gluco-pyranosyl)-α-D-glucopyranosylamine by nmr analysis of its acetate (2) and degradation studies. The structure of the chromophore moiety obtained by acid hydrolysis of 1 was studied by extensive use of long-range selective proton decoupling (LSPD) and deuterium induced upfield shift and was finally determined by X-ray analysis to be 2-amino-9-cyano-4-methoxy-7H-pyrrolo[2,3-d]pyrimidine and therefore the structure of 1 has been established as shown in Fig. 7. Mild acid treatment of 1 resulted in mutarotation to give the β-anomer 6. Both of miharamycins A (10) and B (11) contained 2-aminopurine as a common chromophore, its structure being established by UV and ^<13>C-nmr analysis. Amino acid analyses and ^<13>C-nmr studies revealed the presence of N_5-hydroxyarginine and arginine in 10 and 11, respectively as an amino acid moiety. The remaining sugar moiety (C_9H_<13>NO_7) common to 10 and 11 has been determined to be E in Fig. 12 by ^1H- and ^<13>C-nmr spectral analyses and therefore the total structures of 10 and 11 are shown in Fig. 13.
天然有機化合物討論会の論文
1982-09-10