31 ロイコマイシンの化学XI : LeucomycinのAglyconeの単離,mycaminose上の化学的修飾及び16員環macrolide抗生物質の構造と活性

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We have been studied the relationship between the structures and the biological activities on 16-membered lactone ring macrolide antibiotics. The aglycone moiety from 16-membered macrolides has not been reported, but in the present series of work, we have chemically obtained the aglycone from leucomycin A_3 (LM A_3) (I). Treatment of (I) with m-chloroperbenzoic acid in CHCl_3 gave the N-oxide (II), which was refluxed with Ac_2O in CHCl_3 to obtaine aglycone, leuconolide-A_3 5,18-hemiacetal (III). In the above reaction, a neutral macrolide, 2'-acetyl 3'-desdimethylamino 3'-oxo LM A_3 (X) which 3'-dimethylamino group on mycaminose moiety was converted to ketone carbonyl was isolated from the same reaction product. Furthermore, (I) was reacted with Al-isopropoxide to give 9-dehydro 18-dihydro leucomycin A_3 (V). (V) was oxidized with m-chloroperbenzoic acid to N-oxide (VII), and(VII)was then treated with Ac_2O in CHCl_3 to obtain 9-dehydro 18-dihydro leuconolide-A_3 (VIII). In order to clarify the correlation between the structure and biological activity of mycaminose moiety, various derivatives were synthesized. The antimicrobial activities of the both glycone, (III) and (VIII) completly disappeared, and it was found that the decreasing of electro-density on dimethylamino group on mycaminose moiety resulted in the decrease of the activity.
天然有機化合物討論会の論文
1973-10-01