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.^[2]

Cyanomethine

Names
IUPAC name 4-Amino-2,6-dimethylpyrimidine
Other names Cyanmethine Kyanmethin 6-Amino-2,4-dimethylpyrimidine 2,6-Dimethyl-4-pyrimidinamine 2,6-Dimethylpyrimidin-4-ylamine Trimethyl cyanuride[1] Amidodimethylmetadiazine[2]
Identifiers
CAS Number	461-98-3
3D model (JSmol)	Interactive image
ChemSpider	61354
ECHA InfoCard	100.006.656
EC Number	207-320-1
PubChem CID	68039
CompTox Dashboard (EPA)	DTXSID50196725
InChI InChI=1S/C6H9N3/c1-4-3-6(7)9-5(2)8-4/h3H,1-2H3,(H2,7,8,9) Key: BJJDXAFKCKSLTE-UHFFFAOYSA-N
SMILES CC1=CC(=NC(=N1)C)N
Properties
Chemical formula	C6H9N3
Molar mass	123.159 g·mol−1
Appearance	crystalline solid
Odor	irritating[1]
Melting point	180–185 °C (356–365 °F; 453–458 K)
Solubility in water	soluble
Hazards
GHS labelling:[3]
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P264, P264+P265, P271, P280, P302+P352, P304+P340, P305+P351+P338, P319, P321, P332+P317, P337+P317, P362+P364, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Properties

Cyanomethine is a strongly basic^[4] colourless to white crystalline solid. It is soluble in water and slightly soluble in alcohol.^[1]

Cyanomethine can form complexes with platinum(II) and platinum(IV) compounds.^[5]

Synthesis

Cyanomethine is prepared by the trimerisation of acetonitrile with sodium or potassium,^[6] with the corresponding metal cyanide and C₄H₆N₂ (possibly 2-methylimidazole or 3-methylpyrazole; iminoacetonitrile has been identified^[7]) as the main byproducts.^[8] It can also made by reaction of sodium methoxide and acetonitrile.^[2]

The correspondence of the three acetonitrile units to a tautomer of cyanomethine is:

At higher pressure, sodium methoxide instead catalyzes trimerization to form 2,4,6-Trimethyl-1,3,5-triazine.^[9]

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