Chromomycin a components of the antibiotic chromomycin

摘要

The invention relates to (I) chromomycin A group antibiotics, i.e. chromomycin A1, A2, A3, A4 and A5, containing a major proportion but less than 70% by weight of chromomycin A3; (II) chromomycin (A2+A3) containing at least 70% but less than 100% by weight of chromomycin A3; and (III) chromomycin A3, which has a melting point of 185 DEG C., a molecular weight by the Rast method of 467 sB 50 or by the Barger method of 900-1,000, a specific rotation measured at a wavelength of FORM:0898793/IV (b)/1 (c=1.0% ethanol), an antibiotic spectrum according to Table 4 (not shown), a UV-spectrum PICT:0898793/IV (b)/1 PICT:0898793/IV (b)/2 according to Fig. 1 and an IR-spectrum as shown in Fig. 2a. Chromomycin A group is obtained from chromomycin mixture (chromomycin A, B and C groups) by (a) treating chromomycin mixture with a polyhydric alcohol containing water methanol or ethanol in countercurrent with a solvent-immiscible therewith; (b) dissolving chromomycin mixture in an organic solvent of high polarity, adding an organic solvent of low polarity to precipitate first unundesired fractions and then chromomycin A group; (c) dissolving chromomycin mixture in an organic solvent of high polarity, passing the solution through an adsorbent, treating the adsorbed matter with an organic solvent of low polarity and retrieving chromomycin A group as the component which is least adsorbed; (d) partition chromatography using as eluant ether/acetic acid ester, acetic acid ester/acetone and acetone/alcohol solvent systems in succession, the chromomycin being recovered from the ether/acetic acid ester system. Chromomycin (A2 + A3) is obtained by treating chromomycin A group in an organic solvent of high polarity with a non-polar solvent in a step-wise manner, separating each precipitate formed, repeating the treatment on each precipitate and collecting (A2 + A3) from the middle of the final precipitates. Chromomycin A3 is obtained from chromomycin A group by (a) partition chromatography using as eluant ether/acetic acid ester solvent system (90 : 10 ratio); (b) dissolving the chromomycin A group in a polyhydric alcohol containing water, methanol or ethanol with acetic acid ester/ether mobile phase in counter-current distribution apparatus, the chromomycin A3 being recovered from the middle portions of the apparatus. Specification 898,794 is referred to.