The crystal and molecular structure of the 1:1 adduct hydrate of pyrazine-2,3-dicarboxylic acid with 1,1-diethylurea

The adduct hydrate of 1,1-diethylurea with pyrazine-2,3-dicarboxylic acid, [(CHNO) (CHNO)].HO has been prepared and characterized using low-temperature single-crystal X-ray diffraction methods. A primary asymmetric cyclic hydrogen-bonding interaction, similar to those found in other adducts of 1,1-diethylurea with the nitro-substituted aromatic acids, was found between the amide group of the substituted urea and one carboxylic acid group of the acid. Further peripheral hydrogen-bonding associations involving both the first and the second carboxylic acid groups, urea and the lattice water molecule result in a ribbon polymer structure