Xanthine

Source: Wikipedia, the free encyclopedia.
(Redirected from
Methylxanthines
)
Not to be confused with
Xanthan
.
Xanthine[1]
Names
Preferred IUPAC name
3,7-Dihydro-1H-purine-2,6-dione
Other names
1H-Purine-2,6-dione
Identifiers
3D model (
JSmol
)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard
 100.000.653 Edit this at Wikidata
IUPHAR/BPS
KEGG
UNII
  • InChI=1S/C5H4N4O2/c10-4-2-3(7-1-6-2)8-5(11)9-4/h1H,(H3,6,7,8,9,10,11) checkY
    Key: LRFVTYWOQMYALW-UHFFFAOYSA-N ☒N
  • InChI=1S/C5H4N4O2/c10-4-2-3(7-1-6-2)8-5(11)9-4/h1H,(H3,6,7,8,9,10,11)
  • InChI=1S/C5H4N4O2/c10-4-2-3(7-1-6-2)8-5(11)9-4/h1H,(H3,6,7,8,9,10,11)
    Key: LRFVTYWOQMYALW-UHFFFAOYSA-N
  • c1[nH]c2c(n1)nc(nc2O)O
Properties
C5H4N4O2
Molar mass 152.11 g/mol
Appearance White solid
Melting point decomposes
1 g/ 14.5 L @ 16 °C
1 g/1.4 L @ 100 °C
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
1
0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Xanthine (

base found in most human body tissues and fluids, as well as in other organisms.[2] Several stimulants are derived from xanthine, including caffeine, theophylline, and theobromine.[3][4]

Xanthine is a product on the pathway of

purine degradation.[2]

Xanthine is subsequently converted to uric acid by the action of the xanthine oxidase enzyme.[2]

Use and manufacturing

Xanthine is used as a drug precursor for human and animal medications, and is manufactured as a pesticide ingredient.[2]

Clinical significance

Derivatives of xanthine (known collectively as xanthines) are a group of

sympathomimetic amines, xanthines mainly act to oppose the actions of adenosine, and increase alertness in the central nervous system.[2]

Toxicity

Methylxanthines (

7-methylxanthine (heteroxanthine), among others, affect the airways, increase heart rate and force of contraction, and at high concentrations can cause cardiac arrhythmias.[2] In high doses, they can lead to convulsions that are resistant to anticonvulsants.[2] Methylxanthines induce gastric acid and pepsin secretions in the gastrointestinal tract.[2] Methylxanthines are metabolized by cytochrome P450 in the liver.[2]

If swallowed, inhaled, or exposed to the eyes in high amounts, xanthines can be harmful, and may cause an

allergic reaction if applied topically.[2]

Pharmacology

In in vitro pharmacological studies, xanthines act as both:

  1. competitive nonselective
    innate immunity[6]
    and
  2. nonselective adenosine receptor antagonists [7] which inhibit sleepiness-inducing adenosine.[2]

However, different analogues show varying potency at the numerous subtypes, and a wide range of synthetic xanthines (some nonmethylated) have been developed searching for compounds with greater selectivity for phosphodiesterase enzyme or adenosine receptor subtypes.[2][8][9][10][11][12]

Xanthine: R1 = R2 = R3 = H
Caffeine: R1 = R2 = R3 = CH3
Theobromine: R1 = H, R2 = R3 = CH3
Theophylline: R1 = R2 = CH3, R3 = H
Examples of xanthine derivatives
Name R1 R2 R3 R8
IUPAC nomenclature
 Found in
Xanthine H H H H 3,7-Dihydro-purine-2,6-dione Plants, animals
7-Methylxanthine H H CH3 H 7-methyl-3H-purine-2,6-dione Metabolite of caffeine and theobromine
Theobromine H CH3 CH3 H 3,7-Dihydro-3,7-dimethyl-1H-purine-2,6-dione
guayusa
Theophylline CH3 CH3 H H 1,3-Dimethyl-7H-purine-2,6-dione Tea, cacao (chocolate), yerba mate, kola
Paraxanthine CH3 H CH3 H 1,7-Dimethyl-7H-purine-2,6-dione Animals that have consumed caffeine
Caffeine CH3 CH3 CH3 H 1,3,7-Trimethyl-1H-purine-2,6(3H,7H)-dione
guayusa, Cacao (chocolate
)
8-Chlorotheophylline CH3 CH3 H Cl 8-Chloro-1,3-dimethyl-7H-purine-2,6-dione Synthetic pharmaceutical ingredient
8-Bromotheophylline CH3 CH3 H Br 8-Bromo-1,3-dimethyl-7H-purine-2,6-dione Pamabrom diuretic medication
Diprophylline CH3 CH3 C3H7O2 H 7-(2,3-Dihydroxypropyl)-1,3-dimethyl-3,7-dihydro-1H-purine-2,6-dione Synthetic pharmaceutical ingredient
IBMX CH3 C4H9 H H 1-Methyl-3-(2-methylpropyl)-7H-purine-2,6-dione
Uric acid H H H O 7,9-Dihydro-1H-purine-2,6,8(3H)-trione Byproduct of purine nucleotides metabolism and a normal component of urine

Pathology

People with rare genetic disorders, specifically xanthinuria and Lesch–Nyhan syndrome, lack sufficient xanthine oxidase and cannot convert xanthine to uric acid.[2]

Possible formation in absence of life

Studies reported in 2008, based on 12C/13C

meteorites found on Earth, was published suggesting xanthine and related organic molecules, including the DNA and RNA components adenine and guanine, were found in outer space.[15][16][17]

See also

References

  1. ^ Merck Index, 11th Edition, 9968.
  2. ^ a b c d e f g h i j k l m n o "Xanthine, CID 1188". PubChem, National Library of Medicine, US National Institutes of Health. 2019. Retrieved 28 September 2019.
  3. ISBN 0-8493-2647-8
    .
  4. ^
    ISBN 0-8385-0619-4
    .
  5. PMID 9927365
    .
  6. ^
    PMID 15634873
    .
  7. PMID 3588607
    .
  8. PMID 3806581
    .
  9. PMID 3588607
    .
  10. PMID 1658821
    .
  11. S2CID 23923058
    .
  12. PMID 18181659
    .
  13. S2CID 14309508
    .
  14. ^ AFP Staff (13 June 2008). "We may all be space aliens: study". AFP. Archived from the original on June 17, 2008. Retrieved 2011-08-14.
  15. PMID 21836052
    .
  16. ^ Steigerwald, John (8 August 2011). "NASA Researchers: DNA Building Blocks Can Be Made in Space". NASA. Retrieved 2011-08-10.
  17. ^ ScienceDaily Staff (9 August 2011). "DNA Building Blocks Can Be Made in Space, NASA Evidence Suggests". ScienceDaily. Retrieved 2011-08-09.
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