Any of a class of heterocyclic compounds with a two-ring structure composed of carbon and nitrogen atoms. The simplest member, purine itself (C5H4N4), is not common, but its derivatives with the structure are. Examples are uric acid, caffeine, and two of the nucleotides in nucleic acids, guanine and adenine.
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The general term purines also refers to substituted purines and their tautomers.
The purine is the most widely distributed nitrogen-containing heterocycle in nature.
The name 'purine' (purum uricum) was coined by the German chemist Emil Fischer in 1884. He synthesized it for the first time in 1899. The starting material for the reaction sequence was uric acid (8), which had been isolated from kidney stones by Scheele in 1776. Uric acid (8) was reacted with PCl5 to give 2,6,8-trichloropurine (10), which was converted with HI and PH4I to give 2,6-diiodopurine (11). This latter product was reduced to purine (1) using zinc-dust.
Examples of high purine sources include: sweetbreads, anchovies, sardines, liver, beef, kidneys, brains, meat extracts, herring, mackerel, scallops, game meats, and gravy.
A moderate amount of purine is also contained in beef, pork, poultry, fish and seafood, asparagus, cauliflower, spinach, mushrooms, green peas, lentils, dried peas, beans, oatmeal, wheat bran and wheat germ.
Moderate intake of purine-containing food is not associated with an increased risk of gout.
Purine (1) is obtained in good yield when formamide is heated in an open vessel at 170 oC for 28 hours.
Procedure: Formamide (45 gram) was heated in an open vessel with a condenser for 28 hours in an oil bath at 170-190 oC. After removing excess formamide (32.1 gram) by vacuum distillation, the residue was refluxed with methanol. The methanol solvent was filtered, the solvent removed from the filtrate by vacuum distillation, and almost pure purine obtained; yield 4.93 gram (71 % yield from formamide consumed). Crystallization from acetone afforded purine as colorless crystals; melting point 218 oC.
Oro, Orgel and co-workers have shown that four molecules of HCN tetramerize to form diaminomaleodinitrile (12), which can be converted into almost all important natural occurring purines.
Hereditary disorders of purine and pyrimidine metabolism: Identification of their biochemical phenotypes in the clinical laboratory
Aug 01, 1997; DALIBOR VALIK, M.D AND JAMES D. JONES, PH.D. Objective: To describe a laboratory approach to the diagnosis of hereditary diseases...