Mycinamicins, new macrolide antibiotics. XII. Isolation and structural elucidation of mycinamicins X and XI.

covered four newminor componentsdesignated mycinamicins X (1), X' (2), XI (3) and XI' (4). From physico-chemical properties, spectroscopic data and chemical degradation studies, these compounds were shown to be analogs ofmycinamicins I (5) and II (6), whose structures are different from compounds 5and 6at the C-ll position. In this paper, wedescribe the isolation and structural elucidation of these compounds. The culture nitrates (200ml) of mycinamicinproducing strains of M. griseorubida were extracted with CHC13at pH 7.5. The organic l yer contained mycinamicins.The aqueous layer wasadjusted to pH3.0 with 1n hydrochloric acid. After this solution was adsorbedon Diaion HP-20resin (100ml), the resin was washed with water, and then with 30% aqMeOH. The active componentswere eluted with 80%aq MeOH. Theeluate wasconcentrated in vacuo to give a crude powder.The crude resdue waspurified bypreparative HPLC(YMC-gel ODS1-40/64, 300mmx20mm i.d.) using 0.1m NaH2PO4-MeOH (6:4) and (5:5) as solvent system with detection on 220nm.Fractions (20 ml) were collected at a flow rate of 10ml/minute. Individual fractions were assayedby analytical HPLC. Eachfraction wascollected and combined,and the