From Big Medical Encyclopedia

IMIDAZOLE (synonym: glioksalin, 1,3 diazol color) — the organic compound representing a five-membered heterocycle is a part of some amino acids, alkaloids, vitamins and other physiologically active agents, as a part of active centers of some enzymes, e.g. chymotrypsin, takes part in implementation of the catalytic act. Some derivatives And. are used as pharmaceuticals.

Constitutional formula of an imidazole:

And. is a part not only alkaloids (see), amino acids histidine (see) and isohistidine, but also cordianine, biotin (see), cyclic ureides (see), uric acid (see), purine bases (see), carnosine (see) and anserine (see). There are data that in muscles of salmons And. contains in a free look.

And. it was for the first time received by Debus (N. Debus) in 1858 as a result of effect of ammonia on glyoxal; later it was established that instead of ammonia it is more convenient to take urotropin (hexamethylenetetramine). Homologs And. receive effect of alpha hydroxy-ketones and ammonia on aldehydes in the presence of cupric acetate, reactions of alpha diketones with aldehyde and ammonium acetate in ice acetic to - those or from alpha diketones or the alpha replaced ketones (deputies — haloid, oksi-, amine or izonitrozogruppa) at their interaction from forms amide.

And. let's dissolve in water, alcohol, it is difficult ether-soluble, t ° pl 90 °, t ° kip 256 °, pier. weight 68,08.

And. is amphoteric connection. In solutions can exist in three tautomeric forms:

And. forms salts with alkaline and earth metals, formation of complexes with metals, ATP, indoles and so forth is characteristic of it. And. and its homologs are easily halogenated, sulphurized and nitrated.

In an active center of many enzymes, including proteolytic, the rest of a histidine (he takes a position 57 in a molecule of alpha chymotrypsin) enters, the imidazolny group to-rogo takes part in process of an acid-base catalysis directly or as the nucleophilic agent.

Derivatives And. Naphthyzinum (see), phentolamine (see), Dibazolum (see), Pilocarpinum (see) etc. are used in medical practice as pharmaceuticals. The action spectrum of these connections is quite wide and in many respects is defined by the nature of deputies in I.

Eksperimentalno's ring is established, as. has exciting effect on c. the N of page, oppresses cortical neurons, facilitates neuromuscular transmission (increases probability of release of substance mediator), lowers rectal temperature, strengthens action of analgetics and anesthetics, increases force of cordial reductions, suppresses secretion of a gastric juice. And. in vitro neutralizes action of catecholamines on cardiac and smooth muscles, on fatty tissue, prevents the lipolysis caused by adrenocorticotropic hormone, inhibits effect of thyritropic and parathyroid hormones.

Action And. in certain cases connect with its activating influence on phosphodiesterase — the enzyme destroying cyclic 3', 5' - AMF. The question of communication between action is discussed And. and ion concentration of Ca 2+ in fabrics.

For quantitative and qualitative test And. at biochemical, researches use staining reaction of a diazocombination.

Bibliography: Bernhard S. Struktura and function of enzymes, the lane with English, M., 1971; Bruce T. and Benkovi of the p C. Mechanisms of bioorganic reactions, the lane with English, M., 1970; P about and r with to and y A. F., Hectare the district about in with to and y A. D. and Simonov A. M. Achievements of chemistry of an imidazole, Usp. chemistry, t. 35, century 2, page 261, 1966, bibliogr.; With e in ying S. E ER. Problem of biological activity of natural compounds of an imidazole, Usp. sovr, biol., t. 59, century 2, page 165, 196 5, bibliogr.; Grimmett M.R. Advances in imidazole chemistry, in book: Advanc, heterocyclic chem., ed. by A. R. Katrit-zky a. A. J. Boulton, v. 12, p. 103, N. Y. — L., 1970, bibliogr.

I. M. Gotgilf.