KETONES — an extensive class of the organic compounds playing an important role in the chemistry, biology and medicine supporting the carbonyl group connected to two carbon atoms in the molecule (on type. General formula K.: R — WITH — R', where R and R' — hydrocarbon radicals of various nature.
Biol, and medical value K. multilaterally, and an essential role is played funkts, replaced To., the containing hydroxyl, an amino group and other deputies. Formation of significant amounts aliphatic To. — acetone occurs at a diabetes mellitus and some other patol, states (see. Ketone bodies ). The essential role in processes of metabolism at the person and other mammals is played also by dihydroxy acetone and aminoacetone. Dihydroxy acetone has a number of useful therapeutic properties (activates cardiovascular functions at a collapse and shock, renders protective and to lay down. effect at wet brain and so forth); it is used during the conducting diagnostic tests at assessment of weight of thyrotoxicoses. Steroid To. adrenal hormones are — cortisone (see), corticosterone (see), etc., and also sex hormones — testosterone (see), estrone (see). A row galogenometil-and the diazomethylketones in particular imitating on a structure of amino acid or peptides is applied as inhibitors of proteinases, mutagenic and antineoplastic agents. To. show versatile pharmakol. action, considerable number found them application as pharmaceuticals; a classical example such To. is camphor (see). Among modern to lay down. means keto-amines, hl are emitted. obr. derivatives aliphatic aromatic To. (propiophenone, phenyl propyl ketone, acetophenone), widely used in medical practice. The anesthetizing drugs (Fenadonum), styptic means (adrenalon), local anesthetics (falikain, geksakain, ketokain, etc.), drugs (Ketaminum), cardiovascular means (oxyfedrine, etafenon, propafenon), psychotropic agents (Haloanisonum, pirovaleron, etc.), antihypertensives (fenitron), anticonvulsant substances and Muscle relaxants (Mydocalmum), etc. of Lech concern to them. means are found also among aromatic and heterocyclic To., free of amino groups, napr, ketoprofen (antirheumatic drug), benzbromaron (uricosuric means), metopiron (adrenokortikostatik) and row other. Some synthetic and natural To. have antineoplastic activity. A row alpha and beta keto-amines shows antimicrobic and fungicidal activity.
To. are eurysynusic in the nature. Various To. some meet in plants, aliphatic To. play a role of the frightening-off substances and pheromones (the substances produced by excretory glands of animals and causing changes in behavior of individuals of the same species in insects); macrocyclic To. are a part of musk. Some alkaloids (hygrine, kuskgigrin, lobeline, pseudopelletierine) and antibiotics have a ketonic structure (tetracycline, griseofulvin, etc.). In very small concentration aliphatic To. («methylketones») are included as components of a smell and taste into foodstuff (cheese, oil, fruit, coffee, etc.); To. are found in tobacco and tobacco smoke. In food ketosugar is of great importance — fructose (see). In the nature methylketones are formed as a result of microbic or fungal biosynthesis from fat to - t (hl. obr. by beta oxidation) are also rather end products of a metabolism (in the soil, in foodstuff); perhaps also direct mikrobiol, oxidation of hydrocarbons to K. V tissues of mammals from methylketones contains only acetone.
To. are widely applied in the equipment as solvents and are used in industrial organic synthesis as a feed stock and semi-products; reaction of oximes To. with acid reagents, leading to formation of amides carboxylic to - the t (Beckman's regrouping), found important industrial application by production of capron.
To. are subdivided on aliphatic, alicyclic, aromatic, heterocyclic; various deputies can bear the hydrocarbon remains. Depending on number of carbonyl groups in a molecule K. distinguish mono - di - and polyketones. At identical radicals To. call symmetric, at various — asymmetrical or mixed. To., at which the carbonyl group is in a ring, call cyclic. By rules of the international nomenclature of UVPAC organic compounds, names K. are under construction addition to the name of parent hydrocarbon of the termination - it (sometimes — prefixes okso-) and the figure specifying location of carbonyl group in a chain or a cycle or addition of the word «ketone» to names of the hydrocarbon radicals connected with CO group. E.g., CH 3 COCH 3 — propanon, or dimethyl ketone (acetone), CH 3 CH 2 COCH 2 CH 2 • CH 3 - 3-geksanon, ethyl-N-propilketon, () — ketopentamethylene. To., the including benzene rings, often call «phenons», e.g. C 6 H 5 COC 2 H 5 — propiophenone.
Methods of receiving To. are various. They are received oxidation or dehydrogenation of secondary alcohol (RCHOHR' —> RCOR'), reaction of derivatives carboxylic to - t with meta l of l organic compounds (RCOCl + R'Li -> RCOR' + LiCl), synthesis with participation of acetoacetic ether, acylation of aromatic compounds chlorine anhydrides carboxylic to - t in the presence of aluminum chloride (synthesis aromatic To.) and other ways. For receiving symmetric To. use pyrolysis of metal salts carboxylic to - t:
(RCOO) 2 Ca -> R 2 CO + CaCO 3
(in the equations of reactions of R and R' — hydrocarbon radicals). In the industry To. receive also oxidation of some hydrocarbons (e.g., cyclohexane to cyclohexanone) or decomposition of hydroperoxides of alkylaromatic hydrocarbons (in production of phenol):
Protozoa aliphatic To. — the liquids with a peculiar smell which are rather low-boiling; in water beyond all bounds of a rastvorima only acetone and methylethylketone, with increase in molecular weight temperature of boiling increases, and water solubility decreases. Average homologs aliphatic To. — the high-boiling liquids; the highest To. — solid, quite low-melting substances.
To. — reactive connections. Chemical properties K. hl are caused. obr. carbonyl group, edges owing to polarization it is inclined to accession of various reagents and to substitution of atom O other remains (also through addition reactions), napr, interaction with hydrocianic to - that, sodium bisulphite, a hydrazine, hydroxylamine, etc. Formation of oximes, hydrazones, semicarbazones is widely used for allocation and identification To.; some of such derivatives To. are used in synthesis of medicinal substances.
Thanks to influence of carbonyl group of communication With — H in the methyl and methylene groups adjoining to it are activated and can enter various condensations or substitutions which also find application during the receiving medicinal substances. The activating influence of CO group is shown also in ability To. to enolization that is especially characteristic of beta-diketones:
Recovery To. leads, depending on type of a reducer, to secondary alcohol, to pinacols (ditertiary glycols) or to hydrocarbons. Splitting of C — C-bonds To. occurs only at action of strong oxidizers or special reagents (azotistovodorodny to - you).
A uniform method of the analysis To. does not exist. For qualitative test To. usually use reactions to carbonyl group or its spectral properties. Quantitatively To. determine by the weight method in the form of derivatives (2,4 dinitrophenythydrazones, etc.) or volume methods also by reagents on carbonyl group (hydroxylamine, phenylhydrazine, etc.). Apply also colorimetric, spectrophotometric, polyarografichesky and other methods of the analysis. For definition To. in biol, materials methods with use gas-liquid are developed chromatography (see) in combination with mass spectrometry (see).
Great value To. have for a histochemistry, in a cut many reactions for identification are used To. and especially ketosteroids. The most popular of gistokhy, reactions on To. reactions with phenylhydrazine and dinitrophenylhydrazine, semicarbazide and thiosemicarbazide are.
Bibliography: Kudrin A. H. and Vorobyov V. G. Keto-amines, M., 1970, bibliogr.; Molecular mechanisms of genetic processes, under the editorship of N. P. Dubinin and D. M. Goldfarba, page 89, M., 1972, bibliogr.; Fizer L. and Fizer of M. Organic chemistry, the lane with English, t. 1, page 462, M., 1969; Forney F. W. a. M and of k about v e t z A. J. Biology of methyl ketones, J. Lipid Res., v. 12, p. 383, 1971; Laborit H. e. a. Etude pharmacologique de la of dihydroxya-c£tone, Agressologie, t. 7, p. 581, 1966, bibliogr.; Methoden der organischen Chemie (Houben — Weyl), hrsg. v. E. Muller, Bd 7/T. 2a, Ketone T. 1, Stuttgart, 1973.
A. I. Tochilkin.