Supra­molecular hydrogen-bonding patterns in a 1:1 co-crystal of the N(7)—H tautomeric form of N6-benzoyl­adenine with 4-hy­dr­oxy­benzoic acid

The asymmetric unit of the title co-crystal, C12H9N5O·C7H6O3, contains one mol­ecule of N6-benzoyl­adenine (BA) and one mol­ecule of 4-hy­droxy­benzoic acid (HBA). The N6-benzoyl­adenine (BA) has an N(7)—H tautomeric form with nonprotonated N-1 and N-3 atoms. This tautomeric form is stabilized by a typical intra­molecular N—H⋯O hydrogen bond between the carbonyl (C=O) group and the N(7)—H hydrogen on the Hoogsteen face of the purine ring, forming a graph-set S(7) ring motif. The primary robust R22(8) ring motif is formed in the Watson–Crick face via N—H⋯O and O—H⋯N hydrogen bonds (involving N1, N6—H and the carboxyl group of HBA). Weak inter­actions, such as, C—H⋯π and π–π are also observed in this crystal structure