Cyanomethine

Cyanomethine (4-amino-2,6-dimethylpyrimidine) is an amino and methylated derivative of pyrimidine with the chemical formula C6H9N3, belonging to a class named cyanalkines.

Properties and synthesis
Cyanomethine is a strongly basic colourless to white crystalline solid. It is soluble in water and slightly soluble in alcohol. It is prepared by the trimerisation of acetonitrile with sodium or potassium, with the corresponding metal cyanide and C4H6N2 (possibly 2-methylimidazole or 3-methylpyrazole; iminoacetonitrile has been identified ) as the main byproducts. It can also made by reaction of sodium methoxide and acetonitrile.

The correspondence of the three acetonitrile units to a tautomer of cyanomethine is:
 * Acetonitrile trimerization formal cyanomethine.png

At higher pressure, sodium methoxide instead catalyzes trimerization to form 2,4,6-Trimethyl-1,3,5-triazine.

2,6-Diethyl-5-methyl-4-pyrimidinamine (cyan(o)ethine) is an analogous structure that can be made by trimerization of propionitrile.

Cyanomethine can form complexes with platinum(II) and platinum(IV) compounds.