. The actinomycetes. Actinomycetales. DESCRIPTIONS OF ANTIBIOTICS 179 kali. Slightly soluble in alcohol, acetic acid, ace- tone, dioxane, tetrahydrofuran, and NaHCOs solution. Insoluble in petroleum ether, ether, carbon disulfide, carbon tetrachloride, and water. Ultraviolet absorption spectrum maxima at 523 and 560 ni/n (dioxane), 573 and (Ul ni/x (concen- trated H2S()4), and 588 and 641 niM (NaOH). Red in acetic anhydride, becoming violet-blue with red fluorescence on addition of boric acid with warming. Red in dioxane. Deep blue in concen- trated H2SO4 , becoming red-violet on addition of b
. The actinomycetes. Actinomycetales. DESCRIPTIONS OF ANTIBIOTICS 179 kali. Slightly soluble in alcohol, acetic acid, ace- tone, dioxane, tetrahydrofuran, and NaHCOs solution. Insoluble in petroleum ether, ether, carbon disulfide, carbon tetrachloride, and water. Ultraviolet absorption spectrum maxima at 523 and 560 ni/n (dioxane), 573 and (Ul ni/x (concen- trated H2S()4), and 588 and 641 niM (NaOH). Red in acetic anhydride, becoming violet-blue with red fluorescence on addition of boric acid with warming. Red in dioxane. Deep blue in concen- trated H2SO4 , becoming red-violet on addition of boric acid. Bright blue in NaOH (1, 2). Forms a yellow crystalline triacetate (clustered needles), which gives no absorption of visible light and de- composes without melting at 260°C (2). In the mycelium, it exists mainly as protoactinorhodin (III). Ill is extracted from the dried mycelium with acetone, and precipitates as pink, micro- scopic prisms which turn red at 270°C and de- compose at about 335°C (3). Partial structural formula of actinorhodin (4): rated NaCl. Eluate evaporated to dryness in vacuo. Residue extracted with boiling methanol. Cooling of extract precipitates crude actinorul)in. Purified by chromatography on H2S04-treated alumina, with 85 per cent methanol as solvent and developer. Precipitates from active fractions as helianthate (2). Chemical and physical properties: Basic sub- stance: CeHuNsOo or C,H22Nr,04 . HCl salt: white powder. Dihelianthate: reddish orange needle clusters; 206-214°C. C = ; H = ; N = ; S = or Soluble in water and methanol. Insoluble in ether. Positive biuret, Fehling (on boiling), and KMn04 tests. Negative Sakaguchi and Molisch tests. Dialyzable. Stable to Ijoiling in aqueous solution at pH 6 to 7 for 15 minutes (2). Major component present in crude preparation indistinguishable by paper chroma- tography from pure streptothricin (wet butanol- /3-toluenesulfonic acid) (4). W R2. -H O Ri , R2, R3, R4
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