3-Acetoxy-2-(Acetylamino)pyridinium-1-Squarate

Abstract

The title compound, alternatively known as 3-acetoxy-2-(acetylamino) pyridinium betaine of squaric acid, C<inf>13</inf>H<inf>10</inf>N <inf>2</inf>O<inf>6</inf>, has been synthesized. The bond distances within the squarate ring indicate two possible resonance structures. The mean planes of the pyridinium and squarate systems are inclined at an angle of 24.0 (2)° with respect to one another due to a strong intramolecular hydrogen-bonding interaction between the amide NH group and a squarate O atom. In the extended structure, there are additional weak π-π and π-ring interactions, which also stabilize the crystal structure. © 2005 International Union of Crystallography.