DESCRIPTIONS OF ANTIBIOTICS 



349 



Quest iomycins 



Produced by: Streptoniyces sp. wliich also pro- 

 duces a eurocidin-like antibiotic. 



St/nnni/Dis: Questiomycin A is (i-aminophenoxa- 

 zone; ciuestiomycin B is o-aminophenol. These 

 two chemicals were known to have antitubercular 

 Ui'tivity before the discovery of questiomycins, 

 Imt were not known to be produced by actino- 

 mj'cetes. 6-Aminophenoxazone is closely related 

 to the chroniophore of actinomycin. 



Method of extraction: Broth-filtrate extracted 

 with ethyl acetate. The solvent layer extracted 

 with water at pH 2.5. The water layer contains 

 questiomycin B, and the ethyl acetate contains 

 questiomycin A. Questiomycin A: Ethyl acetate 

 layer extracted with N HCl. The pH of the aque- 

 ous layer is brought up to 2.5; extracted with 

 benzene and concentrated to yield crude ciuestio- 

 mycin A. The crude questiomycin A is dissolved 

 in ethyl acetate and passed through a column of 

 alumina. Elution is carried out with ethyl acetate 

 until a red pigment is completely eluted; the 

 eluate is concentrated. Upon standing, a precipi- 

 tate is formed which is collected, dissolved in 

 anhydrous benzene, and chromutographed 

 through a column of magnesium silicate. A red 

 material is eluted with a benzene-ethyl acetate 

 mixture (4:1). The eluate is concentrated, bring- 

 ing about crystallization. Further purification by 

 sublimation in vacuo at 150°C and recrystallization 

 from ethyl alcohol. Questio))iycin B: The water 

 layer is adjusted to pH 6.0 and extracted with 

 ethyl acetate; evaporated to yield crude ciuestio- 

 mycin B. The crude questiomycin B is dissolved 

 in anhydrous ethyl acetate, and chromatographed 

 over a column of alumina. The column is washed 

 with ethyl acetate, acetone, and methyl alcohol. 

 l*]lution with water. Water extracted with ethyl 

 acetate; evaporated to dryness. Further purifica- 

 tion l)y sublimation in vacuo at 120°C and recrys- 

 tallization from benzene. 



Chemical and physical properties: Questiomycin 

 A: Red crystals. Sublimes above 150°C; m.p. 

 241-244°C (decomposition). C = (37.31%; H = 

 3.98%; N = 12.96%. CiaHgOoN. . Molecular 

 weight, 212.2 (or Rast, 217). Soluble in dimethyl- 

 formamide, glacial acetic acid, and concentrated 

 hydrochloric acid. Slightly soluble in ether, ben- 

 zene, ethyl acetate, chloroform, acetone, ethyl 

 alcohol, and methyl alcohol. Insoluble in petro- 

 leum ether and water. Light-absorption maxima 

 at about 465 and 230 m^ in 0.1 .V HCl; 330 m^ 

 with end-absorption in 0.1 A^ NaOH; 425, 410, and 

 240 mix in cyclohexane. Unstable at alkaline reac- 

 tion. Infrared light absorption given in reference 



1. Questiomycin A was found to be identical with 

 6-aminophenoxazone. (Structural formula given in 

 Chapter 6.) Questiomycin B: Colorless crystals, 

 browning when exposed to atmosphere. Sublimes 

 at 120°C; m.p. 170-175°C. C = 65.80%; H = 6.23%; 

 N = 12.68%. CsHvNO. Molecular weight, 109.12 

 (found, 103). Soluble in water, methyl alcohol, 

 eth^d acetate, and ether. Sparingly soluble in 

 carbon tetrachloride and petroleum ether. Light- 

 absorption maxima at about 230 and 285 m.^l with 

 end-absorption in water. Infrared absorption 

 spectrum given in reference 1. Questiomycin B 

 was found to be identical with o-aminophenol. 

 (Structural formula given in Chapter 6.) This 

 compound is believed to be the l)uilding stone of 

 6-aminophenoxazone. 



Biological activity: Active mainly against myco- 

 bacteria. Some activity against B. subtilis, 

 Monilia formosa, Schizosaccharomyces astospora, 

 and P. chrysogenuni. 



Toxicity: LD.mi (mice) questiomycin A: >4()0 

 mg per kg, tiuestiomvcin B; 300 mg per kg intra- 

 peritoneally. 



Reference: 1. Anzai, K. ct al. J. Antiliiotics 

 (Japan) 13A: 125-132, 1960. 



Qiiiiiocycliiies 



Produced by: Streptoniyces aureofaciens (1). 



Method of extraction: Quinocyeline complex: 

 Broth-filtrate from 2i^-day-old fermentation ex- 

 tracted with ethyl acetate. Extract concentrated. 

 Addition of hexane precipitates the complex. 

 Quinocyeline A and isociuinocycline A: Broth-fil- 

 trate from 1-day-old fermentation extracted with 

 methyl isobutyl ketone. Extract treated with 

 glacial acetic acid and concentrated in vacuo. 

 Concentrate extracted with 0.2 per cent aqueous 

 acetic acid. Aqueous phase adjusted to pH 7 to 

 7.5 and extracted with methylene chloride. Ex- 

 tract treated with glacial acetic acid and CCL . 

 Evaporation of methylene chloride from mixture 

 in vacuo, and CCL remaining extracted with dis- 

 tilled water. Water-extract freeze dried. Reprecipi- 

 tated from methylene chloride to give quinocy- 

 eline A acetate. "Second crop" crystals from 

 filtrates of methylene chloride give mixture (I) of 

 quinocyeline A and its isomer, isoquinocycline A. 

 Purification of I: Methanolic solution stirred with 

 addition of acetone to precipitate isoquinocycline 

 A. Quinocyeline B and isoquinocycline B: Broth- 

 filtrate from a 3-day-old fermentation extracted 

 with methyl isobutyl ketone. Extract stirred with 

 0.2 per cent aqueous acetic acid. Aqueous phase 

 collected and adjusted to pH 7.5, while stirring 

 with methvlene chloride. Solvent treated with 



