title: Crystal structure of 3-(3,4,5-tri-meth-oxy-phen-yl)-1,2,3,4-tetra-hydro-cyclo-penta[b]indole-2-carb-oxy-lic acid.
abstract: In the title compound, C21H21NO5, obtained from a Morita-Baylis-Hillman adduct, the hydrogenated five-membered ring adopts a shallow envelope conformation, with the C atom bearing the carb-oxy-lic acid substituent deviating by 0.237 (1) Å from the mean plane of the other four atoms (r.m.s. deviation = 0.007 Å). The dihedral angle between the fused ring system (all atoms; r.m.s. deviation = 0.057 Å) and the pendant trimeth-oxy benzene ring is 66.65 (3)°. The C atoms of the meta-meth-oxy groups lie close to the plane of the benzene ring [deviations = 0.052 (1) and -0.083 (1) Å], whereas the C atom of the para-meth-oxy group is significantly displaced [deviation = -1.289 (1) Å]. In the crystal, carb-oxy-lic acid inversion dimers generate R 2 (2)(8) loops. The dimers are connected by N-H⋯O hydrogen bonds, forming [011] chains. A C-H⋯O inter-action is also observed.
authors.affiliation: Laboratory of Synthesis of Natural Products and Drugs, Institute of Chemistry, University of Campinas, PO Box 6154 - 13083-970, Campinas, SP, Brazil.
authors.forename: Daniara
authors.initials: D
authors.lastname: Fernandes
authors.affiliation: Laboratory of Single Crystal X-Ray Diffraction, Institute of Chemistry, University of Campinas, PO Box 6154 - 13083-970, Campinas, SP, Brazil.
authors.forename: Deborah de Alencar
authors.initials: Dde A
authors.lastname: Simoni
authors.affiliation: Laboratory of Synthesis of Natural Products and Drugs, Institute of Chemistry, University of Campinas, PO Box 6154 - 13083-970, Campinas, SP, Brazil.
authors.forename: Manoel T
authors.initials: MT
authors.lastname: Rodrigues
authors.affiliation: Laboratory of Synthesis of Natural Products and Drugs, Institute of Chemistry, University of Campinas, PO Box 6154 - 13083-970, Campinas, SP, Brazil.
authors.forename: Marilia S
authors.initials: MS
authors.lastname: Santos
authors.affiliation: Laboratory of Synthesis of Natural Products and Drugs, Institute of Chemistry, University of Campinas, PO Box 6154 - 13083-970, Campinas, SP, Brazil.
authors.forename: Fernando
authors.initials: F
authors.lastname: Coelho
keywords: Morita–Baylis–Hillman adduct; crystal strycture; hydrogen bonding; indole skeleton