title: 3-Carb-oxy-methyl-1H-indole-4-carb-oxy-lic acid.
abstract: In the title compound, C(11)H(9)NO(4), the carboxyl group bonded to the six-membered ring lies close to the plane of the 1H-indole ring system [dihedral angle = 13.13 (9)°], whereas the carb-oxy-lic acid group linked to the five-membered ring by a methyl-ene bridge is close to perpendicular [78.85 (9)°]. In the crystal, O-H⋯O and N-H⋯O hydrogen bonds link the mol-ecules, generating (110) sheets.
authors.affiliation: Ordered Matter Science Research Center, College of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189,  People's Republic of China.
authors.forename: Shulin
authors.initials: S
authors.lastname: Mao