LACTONES

From Big Medical Encyclopedia

LACTONES — the organic compounds representing intramolecular cyclic esters of oxyacids. Lactonic rings are eurysynusic and meet in many natural compounds or are formed in process biol, transformations; e.g., in water solutions gluconic acid (see) forms γ-and δ-lactones. At enzymatic transformations of glyukozo-6-phosphate in a pentozny cycle 6 phosphogluconolactone are formed (see. Carbohydrate metabolism ). Ascorbic acid (see) is a lactone of an enol form hexonic to - you (see. Enola ). Lactone cycles contain Pilocarpinum (see), santonin (see), aglikona of a row cardiac glycosides (see) and many antibiotics. Many L. are toxic. Some L. have antimicrobic and anti-virus properties and are used at disinfection of rooms, objects, etc. In trace amounts of L. meet in milk and dairy products; a lactone is tibetomid — widely applied fragrant substance with a smell of musk.

Depending on the place of short circuit of a cycle distinguish β-, γ-or δ-lactones:

β-, γ-and δ-lactones

Names L. correspond to - there from which they are received. Receive L. in various ways, in particular they are easily formed during the eliminating of water from γ-or δ-oxyacids.......... γ-oxyacids easily spontaneously become isolated in γ-lactones at acidulation of their salts or recovery of anhydrides to - t. Hydroxy butanole acid lactone — L. hydroxy-butyric to - you, are for the first time received in 1873 by A. M. Zaytsev recovery of anhydride amber to - you.

Hydrohalides disconnect lactonic ring therefore are formed halogenated to - you; alkalis hydrolyze L., turning them into salts of the corresponding oxyacids; reacting with ammonia, L. form amides of these to - t. At boiling with water L. partially pass into the corresponding oxyacids. In all cases when education of five - or six-membered rings, aldonic is possible and uranium to - you exist in a form L., e.g. D-δ-глюконолактон and D-δ-глюкуронолак-тон. δ-lactones aldonic to - t are easily hydrolyzed in water solution, and gamma lactones in these conditions are steady.

L. usually represent liquids or fusible solid neutral matters which are overtaken without decomposition.

The special attention is deserved by beta propiolactone which has the most expressed antibacterial properties. It is a colorless liquid, it is dissolved in water (to 37,05% at 25 °) and organic solvents. In water it is hydrolyzed with formation of non-toxic products: hydracrylic and beta and hydroxy-propanoic to - t. In usual conditions beta propiolactone will quickly be polymerized therefore it is recommended to be stored at a temperature not over 4 ° (better at — 20 — 30 °) in ware from neutral glass or plastic.

Toxicity of p-propiolactone depends on a way of its hit in an organism. On experimental animals (white mice) it is shown what at introduction through a mouth of LD50 for beta propiolactone makes 372,5 ± 11 mg/kg of weight, one application of beta propiolactone on leather of experimental animals causes her irritation, and at repeated drawings there are necroses. Aerosols of beta propiolactone in concentration of 6 — 12 g/m 3 at inhalation are toxic for hematothermal.

Solutions of p-propiolactone possess a wide range of antimicrobic action, in concentration of 0,1 — 2,0% cause an inactivation of viruses, and in concentration of 0,5 — 10% — death of vegetative and sporous forms of microorganisms. Beta Propiolactone is in this respect more active than formaldehyde. For disinfection beta propiolactone is especially effective in an aero disperse state. At concentration to g/m3 and relative humidity of 80 — 90% it provides disinfecting of air and surfaces from vegetative forms of microorganisms in 2 hours, and from sporous forms at concentration of 12 g/m3 — for 6 hours

Due to the bystry decomposition of drug on non-toxic products beta propiolactone is used for cold sterilization of products from plastic of medical appointment (devices of extracorporal circulation, etc.), and also for sterilization various biol, objects: transplants, blood plasma, mediums, vaccines, diagnostic drugs, etc. However there are data that beta propiolactone has cancerogenic properties therefore it does not find broad application in this area.



Bibliography: Vashkov V. I. The means and methods of sterilization applied in medicine, M., 1973; To r and m of and X e mm about N d J. Organic chemistry, the lane with English, M., 1964; Lenindzher A. Biochemistry, the lane with English, M., 1976; Nesmeyanov A. N. and Nesmeyanov N. A. Beginnings of organic chemistry, book 1 — 2, M., 1974.


T. I. Istomina.

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