Methyl 9H-xanthene-9-carboxyl-ate.

ABSTRACT

The title compound, C(15)H(12)O(3), was obtained unintentionally as the by-product of an attempted recrystallization from methanol of propantheline bromide, an anti-muscarinic drug. The xanthone unit is folded, with a dihedral angle of 24.81 (9)° between the benzene rings. The ester substituent adopts a trans staggered conformation, with a C-C-O-C torsion angle of 178.4 (1)°. The mol-ecules pack in distinct layers, facilitated by C-H⋯π and weak π-π ring inter-actions. A weak C-H⋯O inter-action also occurs; however, no classical hydrogen bonding is observed.