Purine

Structural formula
General
Surname	Purine
other names	7 H -imidazo [4,5- d ] pyrimidine; 3,5,7-triazaindole; Abbreviation R (Pu r in);
Molecular formula	C 5 H 4 N 4
Brief description	Colorless needles
External identifiers / databases
EC number	204-421-2
ECHA InfoCard	100.004.020
PubChem	1044
Wikidata	Q188261
properties
Molar mass	120.11 g mol −1
Physical state	firmly
density	1.22 g cm −3
Melting point	217 ° C
solubility	soluble in water and in hot ethanol ; insoluble in diethyl ether and chloroform ;
safety instructions
GHS labeling of hazardous substances	no GHS pictograms
	no GHS pictograms
H and P phrases	H: no H-phrases
	P: no P-phrases
Toxicological data	800 mg kg −1 ( LD 50 , rat , ip )
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Purine ( R ) is a heterobicyclic aromatic amine with four nitrogen atoms . Purine is the basic body of the purine group of substances .

Presentation and extraction

The unsubstituted purine does not occur in nature. Emil Fischer succeeded in making the first representation in 1884 by heating uric acid . It is produced by reacting aminoacetonitrile with formamide or, in a modified form, from phthalimidoacetonitrile and trisformaminomethane. A further production is possible in a synthesis based on Wilhelm Traube from 4,5-diaminopyrimidine and anhydrous formic acid .

properties

Physical Properties

Purine forms colorless crystals that melt at 217 ° C. It crystallizes in a rhombic crystal lattice. A combustion enthalpy of −2708 kJ mol ^{−1 was} determined for the solid compound . The corresponding enthalpy of formation is 169.4 kJ mol ⁻¹ .

Chemical properties

The molecule can be viewed as a fused ring system, composed of the two heterocycles pyrimidine (red) and imidazole (green). Therefore its systematic name is 7 H -imidazo [4,5- d ] pyrimidine.

Purine backbone (9 H isomer)

The 7 H -purine is in a tautomeric equilibrium with its isomer , the 9 H -purine .

Tautomerism of purine

Derived connections

Purine alkaloids

Some alkaloids , the purine alkaloids , are also derived from the basic structure of xanthine :

Purine alkaloids
Surname	R ¹	R ²	R ³
caffeine	-CH ₃	-CH ₃	-CH ₃
Theobromine	-H	-CH ₃	-CH ₃
Theophylline	-CH ₃	-CH ₃	-H

Individual evidence

↑ ^a ^b ^c ^d ^e ^f Entry on Purine. In: Römpp Online . Georg Thieme Verlag, accessed December 10, 2014.
↑ ^a ^b ^c D.R. Kirklin, ES Domalski: Enthalpy of combustion of purine , in: J. Chem. Thermodyn. , 1984 , 16 , pp. 633-642; doi : 10.1016 / 0021-9614 (84) 90043-0 .
↑ ^a ^b Data sheet Purine, 98% from Sigma-Aldrich , accessed on February 1, 2013 ( PDF ).
↑ Entry on purine in the ChemIDplus database of the United States National Library of Medicine (NLM) .
↑ ^a ^b ^c Brockhaus ABC Chemie , FA Brockhaus Verlag, Leipzig 1971, p. 1143.
↑ S. Hauptmann, J. Grafe, H. Remane: Textbook of Organic Chemistry , VEB Deutscher Verlag für Grundstoffindustrie Leipzig 1980, p. 560.
^ DG Watson, RM Sweet, RE Marsh: The crystal and molecular structure of purine , in: Acta Cryst. , 1965 , 19 , pp. 573-580; doi : 10.1107 / S0365110X65003900 .

[Römpp-1] ↑ ^a ^b ^c ^d ^e ^f Entry on Purine. In: Römpp Online . Georg Thieme Verlag, accessed December 10, 2014.

[Kirklin-2] D.R. Kirklin, ES Domalski: Enthalpy of combustion of purine , in: J. Chem. Thermodyn. , 1984 , 16 , pp. 633-642; doi : 10.1016 / 0021-9614 (84) 90043-0 .

[Sigma-3] Data sheet Purine, 98% from Sigma-Aldrich , accessed on February 1, 2013 ( PDF ).

[ChemIDplus-4] Entry on purine in the ChemIDplus database of the United States National Library of Medicine (NLM) .

[Brockhaus-5] Brockhaus ABC Chemie , FA Brockhaus Verlag, Leipzig 1971, p. 1143.

[6] S. Hauptmann, J. Grafe, H. Remane: Textbook of Organic Chemistry , VEB Deutscher Verlag für Grundstoffindustrie Leipzig 1980, p. 560.

[7] DG Watson, RM Sweet, RE Marsh: The crystal and molecular structure of purine , in: Acta Cryst. , 1965 , 19 , pp. 573-580; doi : 10.1107 / S0365110X65003900 .