Pyrimidine

Structural formula
General
Surname	Pyrimidine
other names	1,3-diazine Abbreviation: Y (P y rimidin)
Molecular formula	C 4 H 4 N 2
Brief description	colorless to orange compound
External identifiers / databases
CAS number 289-95-2 EC number 206-026-0 ECHA InfoCard 100.005.479 PubChem 9260 Wikidata Q207722
properties
Molar mass	80.09 g mol −1
Physical state	solid to liquid
density	1.016 g cm −3 (25 ° C)
Melting point	20-22 ° C
boiling point	123-124 ° C
Vapor pressure	19 hPa (22 ° C)
solubility	miscible with water, alcohol and ether
Refractive index	1.504 (20 ° C)
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 226-318 P: 210-280-305 + 351 + 338-310
Thermodynamic properties
ΔH f 0	145.9 kJ mol −1 (liquid)
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Pyrimidine is a six-membered heterocyclic aromatic amine with two nitrogen atoms , which is also known as 1,3-diazine according to the systematic nomenclature . The name is derived from the Greek pyr = heat, fire (because of the relationship with pyridine ) and the amidines . Pyrimidine is the base of the pyrimidine group .

structure

As an aza analogue (azalog) of pyridine, pyrimidine is one of the heteroaromatic diazines .

Different representations of the pyrimidine molecule.

Manufacturing

Pyrimidine was first synthesized from barbituric acid by Siegmund Gabriel and James Colman at the end of the 19th century . This was reacted with phosphorus oxychloride to give 2,4,6-trichloropyrimidine. Dehalogenation with zinc powder resulted in the target compound. Dehalogenations were also carried out with 2,4-dichloropyrimidine and tetrachloropyrimidine.

Pyrimidine synthesis from barbituric acid

More than 50 years after Gabriel's discovery, Hellmut Bredereck's working group developed a synthesis from C _{3 building} blocks and formamide . The tetraacetal, 1-methoxy-1,3,3-triethoxypropane, the enol ether 1,3,3-triethoxypropene and the enamine 3-diethylaminopropenal were used as a substitute for the unstable malondialdehyde (propanedial).

Pyrimidine synthesis from 1,3,3-triethoxypropene and formamide

properties

Pyrimidine forms colorless crystals with a characteristic odor, which melt at temperatures above 20–22 ° C. Above the melting point there is a colorless liquid with a normal pressure boiling point of 124 ° C. The heat of vaporization is 49.89 kJ mol ⁻¹ . The enthalpy of combustion was determined to be −2288.9 kJ mol ⁻¹ , the enthalpy of formation to be 143.2 kJ mol ⁻¹ . The compound is easily soluble in water. It forms salts with acids.

literature

• Brockhaus ABC Chemie, FA Brockhaus Verlag Leipzig 1971.
• JA Joule, GF Smith, Heterocyclic Chemistry, Second Edition, Van Nostrand Reinhold Company, London, 1978, ISBN 0-442-30212-6 .

Individual evidence

1. ↑ ^{a b c d e f} Entry on pyrimidine in the GESTIS substance database of the IFA , accessed on January 9, 2019(JavaScript required) .
2. ↑ ^{a b c d} Entry on pyrimidine. In: Römpp Online . Georg Thieme Verlag, accessed on December 9, 2014.
3. ^ The Merck Index . An Encyclopaedia of Chemicals, Drugs and Biologicals . 14th edition, 2006, ISBN 978-0-911910-00-1 , p. 1374.
4. ↑ Data sheet Pyrimidines from Sigma-Aldrich , accessed on April 22, 2011 ( PDF ).
5. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-25.
6. ^ S. Gabriel, James Colman, About the Pyrimidine, Reports of the German Chemical Society, 32: 1525-1538 (1899); doi: 10.1002 / cber.18990320231 .
7. ^ The Merck Index, 11th Edition, Merck and Co., Rahway, USA, 1989, p. 1270.
8. ↑ H. Bredereck, R. Gompper, G. Morlock: Formamide reactions, VIII. A new pyrimidine synthesis , Chemical Reports 90 , 942-952 (1957); doi: 10.1002 / cber.19570900613 .
9. ↑ H. Bredereck, R. Gompper, H. Herlinger: Formamid reactions, XI. Presentation, properties and reactions of pyrimidine , Chemischeberichte, 91 , 2832-2849 (1958); doi: 10.1002 / cber.19580911240 .
10. ↑ CRC Handbook of Data on Organic Compounds, 2nd Edition, Weast, RC and Grasselli, JG, ed (s)., CRC Press, Inc., Boca Raton, FL, 1989, 1.
11. ↑ ^{a b} Nabavian, PM; Sabbah, R .; Chastel, R .; Laffitte, M., Thermodynamique de composes azotes. II. Etude thermochimique des acidic aminobenzoiques, de la pyrimidine, de l'uracile et de la thymine., J. Chim. Phys., 1977, 74, pp. 115-126.