Какво е индола?
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Re: Какво е индола?
1. A white crystalline compound, C8H7N, obtained from coal tar or various plants and produced by the bacterial decomposition of tryptophan in the intestine. It is used in perfumery and as a reagent. 2. Any of various derivatives of this compound.
Nadqvam se 4e nqma6 problem s english language. Ako se 4udi6 kakvo e triptofan, tova e aminokiselina.
Nadqvam se 4e nqma6 problem s english language. Ako se 4udi6 kakvo e triptofan, tova e aminokiselina.
в отговор на Дидko Любoпитko
#6
Re: Какво е индола?
моля обърнете внимание че не се казва индол а инден
в отговор на Дидko Любoпитko
#7
Re: Какво е индола?
Дано си добре с английския: Indole [120-72-9] , 1-benzo(b)pyrrole, C8H7N, was discovered by A. v. BAEYER and C. A. KNOP in 1866 as the basic structure of the natural dye, indigo, from which it was obtained. In 1910, R. WEISSGERBER found indole in coal tar. Physical Properties. Indole, Mr117.15, mp 52.5 °C, bp 254.7 °C (101.3 kPa), d 1.22 g/cm3 (18 °C), forms colorless, shiny flakes with a slight jasmine aroma. It is readily soluble in ethanol, diethyl ether, and benzene, soluble in hot water, slightly soluble in cold water, and volatile in steam. The heat of combustion is 3.650 kJ/kg (25 °C), the enthalpy of vaporization 597.5 kJ/kg (10.3 – 27.4 °C), and the dipole moment 2.11 D (benzene).
Chemical Properties. As a secondary amine, indole has a hydrogen atom which can be substituted by alkali metals. Oxidation leads to indigo, mild hydrogenation to 2,3-dihydroindole (indoline). Diindole, triindole, and resinification products are obtained upon treatment with acids. High-temperature coal tar contains on average just under 0.2 % indole. In coal tar distillation, the indole is concentrated in a biphenyl – indole fraction which boils between 245 and 255 °C. Following extraction of phenols and bases, the indole is isolated from this fraction and separated from the other major component biphenyl, whose boiling point is only 0.3 °C higher. This is achieved by melting with potassium hydroxide to give the potassium salt of indole, by azeotropic distillation with diethylene glycol, or by extraction with selective solvents (e.g., glycols, aqueous dimethyl sulfoxide, or monoethanolamine). The crude indole can then be purified by crystallization from aliphatic hydrocarbon solvents.
In addition to its recovery from coal tar, indole is also synthesized in technical quantities.
Toxicology
Apart from contact during production and manufacture of indole, human exposure results from smoking and intestinal degradation of nutritional L-tryptophan. Indole is readily absorbed from the gastrointestinal tract and rapidly converted by the liver, e.g., to indican and oxindole, which are excreted mainly into the urine. The acute oral LD50 is 1000 – 1100 mg/kg in rats and about 500 mg/kg in mice. Autopsy after acute exposure revealed hemorrhages and hyperemia of inner organs and tissues. Upon application to the skin and eyes of rabbits, slight temporary irritation was observed. Unlike 3-methylindole (skatole), indole does not induce pulmonary injury in cattle after repeated oral application. At high chronic dosage (20 – 200 mg kg–1 d–1 orally and subcutaneously in mice, rats, rabbits, and dogs for more than three months), indole resulted in a shift in the blood cell differential picture (anemia, leukocytosis, or leukopenia) ; with persistently high intoxication, the development of leukemia cannot be ruled out. In cattle, hemolysis and hemoglobinuric nephrosis were observed after several oral doses of indole (100 or 200 mg/kg). Although there is no other experimental evidence for its cancerogenic potential, indole may influence the formation of tumors caused by other agents. Thus, very high oral doses (800 mg kg–1 d–1) have been reported to accelerate the development of tar-induced skin tumors in mice and 2-acetylaminofluorene-induced bladder carcinomas in hamsters and rats. On the other hand, it simultaneously seemed to suppress 2-acetylaminofluorene-induced hepato-carcinogenesis. A genotoxic effect of indole was confirmed in the Ames test in combination with other mutagenic agents. However, indole itself was neither mutagenic in the Ames test, nor in a cell transformation test, although in a DNA repair assay with Bacillus subtilis, indole caused reparable DNA damagе.
Ullmann 2002
Chemical Properties. As a secondary amine, indole has a hydrogen atom which can be substituted by alkali metals. Oxidation leads to indigo, mild hydrogenation to 2,3-dihydroindole (indoline). Diindole, triindole, and resinification products are obtained upon treatment with acids. High-temperature coal tar contains on average just under 0.2 % indole. In coal tar distillation, the indole is concentrated in a biphenyl – indole fraction which boils between 245 and 255 °C. Following extraction of phenols and bases, the indole is isolated from this fraction and separated from the other major component biphenyl, whose boiling point is only 0.3 °C higher. This is achieved by melting with potassium hydroxide to give the potassium salt of indole, by azeotropic distillation with diethylene glycol, or by extraction with selective solvents (e.g., glycols, aqueous dimethyl sulfoxide, or monoethanolamine). The crude indole can then be purified by crystallization from aliphatic hydrocarbon solvents.
In addition to its recovery from coal tar, indole is also synthesized in technical quantities.
Toxicology
Apart from contact during production and manufacture of indole, human exposure results from smoking and intestinal degradation of nutritional L-tryptophan. Indole is readily absorbed from the gastrointestinal tract and rapidly converted by the liver, e.g., to indican and oxindole, which are excreted mainly into the urine. The acute oral LD50 is 1000 – 1100 mg/kg in rats and about 500 mg/kg in mice. Autopsy after acute exposure revealed hemorrhages and hyperemia of inner organs and tissues. Upon application to the skin and eyes of rabbits, slight temporary irritation was observed. Unlike 3-methylindole (skatole), indole does not induce pulmonary injury in cattle after repeated oral application. At high chronic dosage (20 – 200 mg kg–1 d–1 orally and subcutaneously in mice, rats, rabbits, and dogs for more than three months), indole resulted in a shift in the blood cell differential picture (anemia, leukocytosis, or leukopenia) ; with persistently high intoxication, the development of leukemia cannot be ruled out. In cattle, hemolysis and hemoglobinuric nephrosis were observed after several oral doses of indole (100 or 200 mg/kg). Although there is no other experimental evidence for its cancerogenic potential, indole may influence the formation of tumors caused by other agents. Thus, very high oral doses (800 mg kg–1 d–1) have been reported to accelerate the development of tar-induced skin tumors in mice and 2-acetylaminofluorene-induced bladder carcinomas in hamsters and rats. On the other hand, it simultaneously seemed to suppress 2-acetylaminofluorene-induced hepato-carcinogenesis. A genotoxic effect of indole was confirmed in the Ames test in combination with other mutagenic agents. However, indole itself was neither mutagenic in the Ames test, nor in a cell transformation test, although in a DNA repair assay with Bacillus subtilis, indole caused reparable DNA damagе.
Ullmann 2002
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в отговор на astral_projection
#9
Re: Какво е индола?
прокекция ! че всеки може да намери в интернет НЕ е вярно ( не лесно, не сам!) че е копи/пейст, така е, ма съм написал източника, т.е. цитирам. спамър
