5,8-Dimethoxy-1-naphthoic acid and methyl 5,8-dimethoxy-1-naphthoate

In 5,8-dimethoxy-1-naphthoic acid, C13H12O4, hydrogen bonding is of the cyclic dimer type. The acid H atom is modelled as being distributed equally over two sites. In addition to the conventional hydrogen bonds, there are three significantly attractive C-H...O interactions. The dihedral angle between the naphthalene core plane and the carboxyl plane is 80.0 (1) degrees. In methyl 5,8-dimethoxy-1-naphthoate, C14H14O4, there are no conventional hydrogen bonds but there are three significantly attractive C-H...O interactions. With the exception of the C-O distances in the carboxyl groups, the molecular geometries of the acid and the ester are quite similar.