Pyrimidine

Colorless to orange-colored compound

Solid to liquid

1.016 g · cm -3 ( 25 ° C)

20-22 ° C.

123-124 ° C

19 hPa ( 22 ° C)

Miscible with water, alcohol and ether

1.504 (20 ° C)

Attention

145.9 kJ · mol -1 (liquid)

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Pyrimidine is a six membered heterocyclic aromatic organic compound with two nitrogen atoms, which is referred to according to the systematic nomenclature as 1,3- diazine. The name derives from gr pyr = heat, fire off ( because of the relationship to pyridine) and the class of amidines. Pyrimidine is the base body of the substance group of pyrimidines.

Structure

Pyrimidine count as an aza - analogue ( Azalog ) of pyridine to the heteroaromatic diazines.

Production

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

About 50 years after Gabriel's discovery a synthesis of C3 - blocks and formamide was developed in the working group to Hellmut Bredereck. As a substitute for unstable malondialdehyde ( propanedial ) which were Tetraacetal, 1 -methoxy-1 ,3,3- triethoxypropan, the enol ether and the 1,3,3- Triethoxypropen enamine 3 Diethylaminopropenal used.

Properties

Pyrimidine forms colorless, characteristic smelling crystals that melt already above 20-22 ° C. Above the melting point is a colorless liquid with a boiling point before normal pressure at 124 ° C. The heat of vaporization is 49.89 kJ · mol -1. The heat of combustion was determined with -2288.9 kJ · mol -1, the enthalpy of formation of 143.2 kJ · mol -1. The compound is readily soluble in water. With acids it forms salts.