Xanthine

Structural formula
General
Surname	Xanthine
other names	2,6-dihydroxypurine 2.6 (1 H , 3 H ) -Purindion 2.6 (1 H , 3 H ) -Purindiol XANTHINE ( INCI )
Molecular formula	C 5 H 4 N 4 O 2
Brief description	colorless solid
External identifiers / databases
CAS number 69-89-6 EC number 200-718-6 ECHA InfoCard 100,000,653 PubChem 1188 ChemSpider 1151 DrugBank DB02134 Wikidata Q50980
properties
Molar mass	152.11 g · mol -1
Physical state	firmly
Melting point	350 ° C
solubility	very little water soluble (69 mg l −1 at 16 ° C)
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 317-319 P: 280-305 + 351 + 338
Toxicological data	> 3333 mg kg −1 ( LD 50 ,  mouse ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Xanthine is a naturally occurring substance of the nucleotide metabolism . It is an intermediate product in the breakdown of purines and is converted into uric acid by xanthine oxidase . In addition, xanthine is the lead substance of the group of xanthines, which includes the purine alkaloids caffeine , theobromine and theophylline from tea leaves , coffee beans , cocoa , cola nuts , mate and guarana .

Occurrence

Xanthine is an intermediate product of purine degradation by hydroxylation at positions 2 and 6; the resulting Dilactim tautomerizes completely to Di lactam . It arises z. B. in wine in small quantities through the self-digestion of yeasts . It is also found in coffee beans, potatoes , tea leaves and mate, the Argentine national drink. There it is said to have a stimulating effect due to its special structure. In the human body, some organs such as the blood, muscles and liver contain xanthine, which is also excreted in the urine .

properties

Xanthine is a colorless, crystalline solid that dissolves well in ethyl acetate , acids and bases, very little (69 mg · l ⁻¹ ) in water at 16 ° C and only moderately in hot water and ethanol .

The nucleoside xanthosine and the nucleotide xanthosine monophosphate are derived from xanthine .

It is used together with 2,4-diaminopyrimidine to investigate unusual base pairings in DNA .

Pathophysiology

Xanthine stones are relatively rare. They can occur with xanthinuria . The cause of the not so rare xanthinuria is a genetic defect in xanthine oxidase. Since xanthine is medically relatively soluble in water , only about 40% of those affected develop urinary stones . Xanthinuria can also occur with treatment with allopurinol . Allopurinol inhibits xanthine oxidase and as a medicament for lowering serum uric acid levels (especially when gout - patients ) were used. If the fluid intake is too low, a xanthine concentration that is critical for stone formation can be reached in the urine .

Individual evidence

1. ↑ Entry on XANTHINE in the CosIng database of the EU Commission, accessed on March 29, 2020.
2. ↑ ^{a b c d} Entry on xanthine. In: Römpp Online . Georg Thieme Verlag, accessed on May 24, 2012.
3. ↑ ^{a b c} Entry on xanthine in the ChemIDplus database of the United States National Library of Medicine (NLM) .
4. ↑ ^{a b} Xanthine data sheet from Sigma-Aldrich , accessed on April 25, 2011 ( PDF ).
5. ↑ ^{a b} Ammon, HPT: Hunnius Pharmaceutical Dictionary , Walter de Gruyter, 2004, ISBN 3-11-017487-1 , p. 1623.
6. ↑ ST Madariaga, JG Contreras: "Tautomerism of xanthine and its pairing with 2,6-diaminopyrimidine: An ab initio study in the gas phase and aqueous solution", J. Chil. Chem. Soc. , 2003 , 48  (4), pp. 129-133 ( doi: 10.4067 / S0717-97072003000400021 ).

Web links

Commons : Xanthine  - collection of images, videos and audio files

Wiktionary: Xanthin  - explanations of meanings, word origins, synonyms, translations

• Entry for xanthines in the Human Metabolome Database (HMDB) , accessed November 3, 2013.