QUINONES

From Big Medical Encyclopedia

QUINONES — the cyclic diketo-na having nek-ry properties of connections of an aromatic series. In live organisms quinones participate in electron transfer in the course of oxidizing phosphorylation (see biological oxidation) and photosynthesis (see). Redoxreactions (see) with participation of quinones are the cornerstone of fermentation of tea and tobacco. At mold mushrooms quinones are intermediate products in biosynthesis of tetracyclines (see) and aflatoxins (see), and also pigments (see). Treat such pigments, e.g., fumigatin, spinulosin, foentsitin, etc. In a number of plants the quinones having properties of antibiotics (see), such is biflorin from Capraria biflora, or dyes — lauson from henna, alizarine from roots of a madder, and also being toxicants, napr, tikhinon from wood of a tic contain. In prak-ticheskokh! activity of the person quinones are used for the photo, at production of dyes (anthraquinone, alizarine colors, etc.) or as the dehydrogenating agents at organic synthesis, including at synthesis of a number of pharmaceuticals. On the productions connected with their receiving or use, quinones can represent professional harm.

The generic name «quinone» appeared after synthesis by A. A. Voznesensky in 1838 of the first member of connections of this row — 7g-quinone by oxidation cinchonic to - you dioxide (dioxide) of manganese in sulfuric to - those. Quinones easily turn out oxidation of phenols (see), hi-nol, arylamines and diamines. As oxidizers at the same time use Fermi's salt (nitro-zodisulfonat potassium), chromic to - that, silver carbonate on celite, difenilselenovy anhydride, etc. In live organisms oxidation of phenols to quinones is catalyzed by enzyme of polifenoloksidazy (KF 1.14.18.1).

Depending on structure of an aromatic part of a molecule distinguish quinones, naphthoquinones, anthraquinones, phenanthrenquinones, naf-


CHINOCIDUM of 521

tatsenkhinona, a pentatsenkhinona, benz-anthracenequinones, dibenzpirenkhino-na, etc. On an arrangement of oxygen atoms quinones divide on orto-and iara-quinones (meta-quinones do not exist). In most cases

au quinones are painted in orange or red color, «-quinones — in yellow. The elementary and. - quinone — 1,4 quinone at crystallization of water or petroleum ether form yellow prismatic crystals with £ °pl 116 °, slightly soluble in a cold water. Crystals are easily sublimated, have a caustic smell. Elementary au quinone — 1,2-bin-zokhinon forms inodorous unstable bright red crystal flakes with g°pl 60 — 70 °. Naphthoquinones represent flying solid matters, but much less reactive; 9,10 anthraquinone — very steady pale yellow substance with £ °pl 286 °, we will slightly dissolve in usual organic solvents.

Spectroscopic properties of quinones remind properties and, | 3-unsaturated ketones. Quinones, as well as and, r-unsaturated ketones, enter substitution reactions and accessions. Characteristic property of quinones is their ability to be recovered to completely aromatic compounds — hydrochinones (see). The main distinctiveness of quinones is that they accept one electron with education semikhinonovy radical anion in the beginning — functionally the most important and universal group of free radicals (see Radicals free) in the living cells which are constantly formed in the course of a metabolism and energy (see). Further seven-hinonovy radical anion attaches one more electron and turns into dianion. In live organisms this process of reversible recovery of a certain group 2,3-dimetoksi 5-of methylquinones with a side chain from various number of the isoprene remains called by ubikhinona or coenzymes of Q (see Coenzymes) and plastokhinona-m, is the cornerstone of electron transfer in respiratory and fotosinte-tichesky chains, reaction of oxidizing phosphorylation (see).

Quantitatively quinones determine by a difference of light absorption by solution before recovery by dithionite or borgidridy sodium in alkaline condition (usually at the same time solution is painted in bright red or violet color); on reaction of hydrazonoeducation with an arylhydra-zinami; on staining reaction with active methylene connections — nitromethane, propane dinitrile, acetoacetic ether, and also with ammonia in spirit solutions.

Quinones as professional harm. Many quinones are used in industrial organic synthesis as initial products during the receiving pharmaceuticals, dyes, hydrochinone, etc. Tetrachloroquinone is a part of nek-ry insecticides, 2,3-dy ENT specialist-1,4-naphthoquinone is applied

as fungicide, to a protravlivaniye of seeds, etc., 9,10 anthraquinone is used as a repellent. During the work with quinones it is necessary to consider that at long contact almost all of them can be the cause of development of anemia (see), methemoglobinemias (see), to cause damages of a liver, to break exchange of a number of vitamins (especially ascorbic to - you), oppressing activity of many fermental systems, to block SH enzymes. There are data that quinones are capable to kumulirovatsya in an organism, especially in fatty tissue. They are brought from a human body partially in not changed look, partially in the form of conjugates from a glucuronic p by a chamois to-tami. Couples and aerosols of quinones render irritant action on a mucous membrane of upper respiratory tracts and a conjunctiva.

It is noted that toxicity of quinones decreases from quinones to naphthoquinones; introduction to a molecule of quinones of halogens (see) also reduces their toxic properties.

Hron. poisonings with couples and aerosols of quinones are clinically shown sharp razdrazheniyekhm conjunctivas, dacryagogue, burning in a nasopharynx, by pain behind a breast, feeling of constraint in a breast, short wind, cough. Cases of contact dermatitis are noted (see).

Acute poisonings with quinones are possible at their intake, however the picture of acute poisonings is studied only in experimental conditions. At introduction to a stomach of experimental animal lethal doses and - naphthoquinone in 1 — 2 days there came death.

Emergency treatment at inhalation intoxication quinones consists in washing of eyes, a nose and nasopharynx of 2% solution of hydrosodium carbonate and an instillation in eyes of 0,5% of solution of Dicainum, alkaline inhalations, drink of warm milk with soda are recommended. The patient needs to provide rest and heat. In case of development of a bronchospasm (see) add ephedrine to inhalation mixes, at painful cough appoint codeine, dionine. At the phenomena of a methemoglobinemia the victim is given ascorbic to - that (0,5 g), Cystaminum (0,3 g) or rat anti-acrodynia factor (0,05 g), nicotinic to - that (0,05 g) and lipoic to - that (0,05 g). In hard cases hospitalization is necessary. Further treatment — symptomatic, the dietotherapy is shown.

Measures of prevention of intoxication quinones consist in elimination of dust formation and dusting off and vapors of quinones from air of a working zone, obligatory use of industrial respirators (see) like «Petal-200», «Petal-5» with a half mask, etc., protective hermetic points (see), protective gloves and overalls (see Clothes special). Working in continuous contact with quinones and naphthoquinones at employment shall undergo preliminary medical examination (see. Medical examination) and periodic medical examinations at least 1 time in 12 months. As contraindications to revenues to the work connected with contact with quinones serve diseases of blood, a liver, frustration of a metabolism of a neuroendocrinal origin, a disease of skin and inflammatory diseases of eyes.

Maximum allowable concentrations in air of a working zone for/g quinone 0,05 mg/m3, for tetrachloroquinone

of 1 mg/m3, for and - naphthoquinone of 0,1 mg/m3. Bibliography: Harmful substances in the industry, under the editorship of N. V. Lazarev and E. N. Levina, t. 2, page 361, L., 1976;

Karrer P. A course of organic chemistry, the lane with it., page 72, etc., L., 1960.

N. G. Budkovskaya (gigabyte.), V. A. Pekkel

(chemical).

Яндекс.Метрика