Nitronate
A nitronate (IUPAC: azinate) in organic chemistry is a functional group with the general structure R1R2C=NO−
2.[1] It is the anion of a nitronic acid, a tautomeric form of a nitro compound. Just as ketones and aldehydes exist in equilibrium with their enol tautomer in basic and acidic conditions, nitro compounds exist in equilibrium under basic conditions with their nitronate tautomer. The base deprotonates the α carbon, or the carbon directly attached to the nitrogen. The nitronate has two different resonance structures, one with a negative charge on the α carbon and a double bond between the nitrogen and one of the oxygens, and another resonance structure with a double bond between the nitrogen and the α carbon, and no double bond between the nitrogen and the oxygens. A nitronic acid is also called an aci form. In the Nef reaction nitronic acids are degraded to ketones. They can be alkylated on oxygen and used as a dipole in 1,3-dipolar cycloadditions.