Methyl 9H-xanthene-9-carboxyl­ate

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 anti­muscarinic 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 mol­ecules pack in distinct layers, facilitated by C—H⋯π and weak π–π ring inter­actions. A weak C—H⋯O inter­action also occurs; however, no classical hydrogen bonding is observed.