Indane-1,2,3-trione
Indane-1,2,3-trione is the organic compound with the formula C6H43. The compound is the dehydrated derivative of C6H42C2, known as ninhydrin, which is used to reveal fingerprints.
Indane-1,2,3-trione, which reacts readily with nucleophiles. Whereas for most carbonyl compounds, a carbonyl form is more stable than a product of water addition, ninhydrin forms a stable hydrate of the central carbon because of the destabilizing effect of the adjacent carbonyl groups.
To generate the ninhydrin chromophore, the amine must condense to give a Schiff base. The reaction of ninhydrin with secondary amines gives an iminium salt, which is also coloured, generally being yellow–orange.