Индол

Описание

Indole has an almost floral odor when highly purified. Otherwise, it exhibits the characteristic odor of feces. It is not very stable on exposure to light (turns red). Indole may be obtained from the 220 - 260°C boiling fraction of coal tar or by heating sodium phenylglycine-o-carboxylate with NaOH, saturating the aqueous solution of the melt with C 02, and finally reducing with sodium amalgam; can be prepared also by the reduction of indoxyl, indoxyl carboxylic acid, or indigo.

Химические свойства

Indole has an unpleasant odor at high concentration, odor becomes floral at higher dilutions

Физические свойства

Colorless to yellow scales with an unpleasant odor. Turns red on exposure to light and air. Odor threshold of 0.14 ppm was reported by Buttery et al. (1988).

Вхождение

Reported occurring in several natural products as a complex compound that decomposes during enfleurage or steam distillation yielding free indole; reported found in the essential oil from flower of Jasminum grandiflorum, in neroli oil and in the oil extracted from flowers of bitter orange; also reported in the flowers of several plants: lemon, coffee, Hevea brasiliensis and Randia formosa in the oil extracted from flowers of Jasminum odoratissinium L. and in the oil of Narcissus jonquilla. Also reported found in apricot, mandarin orange peel oil, grapes, kohlrabi, French fried potato, crispbread, cheeses, butter, milk, milk powder, boiled egg, fish oil, chicken, beef, pork, beer, rum, Finnish whiskey, red and white wine, coffee, tea, soybean, mushrooms, cauliflower, figs, rice, licorice, buckwheat, malt, wort, elder flower, clary sage, shrimp, okra, crab, clam, squid and green maté

Использование

In highly dil solutions the odor is pleasant, hence indole has been used in perfumery.

Подготовка

Obtained from the 220 to 260°C boiling fraction of coal tar or by heating sodium phenyl-glycine-o-carboxylate with NaOH, saturating the aqueous solution of the melt with CO2 and finally reducing with sodium amalgam; can be prepared also by the reduction of indoxyl, indoxyl carboxylic acid or indigo.

Определение

indole: A yellow solid, C₈H₇N, m.p.52°C. Its molecules consist of a benzenering fused to a nitrogen-containingfive-membered ring. It occurs insome plants and in coal tar, and isproduced in faeces by bacterial action.It is used in making perfumes.Indole has the nitrogen atom positionednext to the fused benzenering. An isomer with the nitrogentwo atoms away from the fused ringis called isoindole.

Общее описание

Indole is classified under the volatile flavor compounds (VFCs). It is known to play significant role in various biological functions such as anti-inflammatory, anticonvulsant, cardiovascular and antibacterial activities.

Опасность

A carcinogen.

Угроза здоровью

Low to moderate toxicity was observed inexperimental animals resulting from oral orsubcutaneous administration of indole. Theoral LD50 value in rats is 1000 mg/kg. It is ananimal carcinogen. It caused tumors in bloodand lungs in mice subjected to subcutaneousadministration.

Пожароопасность

Noncombustible solid.

Экологическая судьба

Biological. In 9% anaerobic municipal sludge, indole degraded to 1,3-dihydro-2H-indol-2-one (oxindole), which degraded to methane and carbon dioxide (Berry et al., 1987). Heukelekian and Rand (1955) reported a 5-d BOD value of 1.70 g/g which is 65.4% of the ThOD value of 2.48 g/g.
Chemical/Physical. The aqueous chlorination of indole by hypochlorite/hypochlorous acid, chlorine dioxide, and chloramines produced oxindole, isatin, and possibly 3-chloroindole (Lin and Carlson, 1984).

Метаболический путь

The indole is metabolized in a mineral salt medium inoculated with 9% anaerobically digested nitrate- reducing sewage sludge, resulting in the sequential occurrence of four structurally related compounds: oxindole, isatine, dioxindole, and anthranilic acid. Indole is metabolized by fungus via indoxyl (3-hydroxyindole), N-formylanthranilic acid, anthranilic acid, 2,3-dihydroxybenzoic acid, and catecol, which is further degraded by an ortho cleavage.

Метаболизм

Indole is oxidized to 3-hydroxyindole (indoxyl) which is conjugated with glucuronic and sulphuric acids before excretion. The sulphate conjugate seems to be the main product in rabbits and, even with relatively large doses of indole, the sulphate conjugation always exceeds that of glucuronic acid(Williams, 1959).

Методы очистки

It can be further purified by sublimation in a vacuum or by zone melting. The picrate forms orange crystals from EtOH and has m 175o. [Beilstein 20 II 196, 20 III/IV 3176, 20/7 V 5.]