Chlorflavonin

摘要

1,139,041. The antibiotic chlorflavonin. BEECHAM GROUP Ltd. 17 May, 1967 [25 May, 1966], No. 23329/66. Heading C2A. The invention relates to an antibacterial and antifungal antibiotic chlorflavonin of structural formula i.e. 31 - chloro - 5: 21 - dihydroxy - 3: 7: 8 - trimethoxy flavone. The antibiotic is produced by cultivating a chlorflavonin-producing strain of Aspergillus candidus, e.g. A.T.C.C. 20022 or A.T.C.C. 20023, under aerobic conditions in an aqueous nutrient solution containing inorganic salts and a source of assimilable carbon and assimilable nitrogen. The antibiotic is isolated from the fermentation broth by adjusting to pH 4À0 to 5À0 with H 2 SO 4 , separating the mycelium and extracting the mycelium with a hydrocarbon solvent, e.g. SBP6 (Shell-Mex Ltd.) and concentrating the extract in vacuo in order to precipitate the antibiotic. A pure substance is obtained by re-crystallization from benzene or petroleum ether. The antibiotic is a pale yellow micro-crystalline solid having a melting- point of 212‹ C. and which sublimes at 150- 160‹ C. (4 mm. Hg). It is almost insoluble in water at neutral pH but soluble in water at alkaline pH. It is soluble in ethanol and chloroform but less so in paraffinic solvents. It forms a diacetate and a dimethyl ether. On elementary analysis, it contains C=57À20%, H=3.88%, Cl=8À93%, OMe=24À78% and OH=7À82%. Alkaline hydrolysis gives 3- chloro-salicylic acid and 4,5-dimethoxy resorcinol. On reduction with magnesium and hydrochloric acid, it gives a deep red colour.