2-Amino-4-(4-pyridyl)pyrimidine and the 1 : 1 adduct with 4-aminobenzoic acid

The structure of the title compound, C9H8N4, comprises nonplanar molecules that associate via pyrimidine N-H . . .N dimer R-2(2)(8) hydrogen-bonding a ssociations [N . . .N 3.1870 (17) Angstrom] and form linear hydrogen-bonded chains via a pyrimidine NH . . .N(pyridyl) interaction [N . .N 3.0295 (19) Angstrom]. The dihedral angle between the two rings is 24.57 (5)degrees. T he structure of the 1:1 adduct with 4-aminobenzoic acid, C9H8N4.C7H7NO2, ex hibits a hydrogen-bonding network involving COOH . .N(pyridyl) [O . .N 2.64 06 (17) Angstrom], pyrimidine N-H . . .N [N . . .N 3.0737 (19) and 3.1755 ( 18) Angstrom] and acid N-H . . .O interactions [N . . .O 3.0609 (17) and 2. 981 (2) Angstrom]. The dihedral angle between the two linked rings of the b ase is 38.49 (6)degrees and the carboxylic acid group binds to the stronger base group in contrast to the (less basic) complementary hydrogen-bonding site.