(±)-trans-6,7-Dimethoxy-1-oxo-3-(2-thienyl)isochroman-4-carboxylic acid

• Main Authors: Mehmet Akkurt, Zeliha Baktır, Milen G. Bogdanov, Ivan V. Svinyarov, Orhan Büyükgüngör
• Format: Article
• Language: English
• Published: International Union of Crystallography 2009-06-01
• Series: Acta Crystallographica Section E
• Online Access: http://scripts.iucr.org/cgi-bin/paper?S1600536809018844

The title compound, C16H14O6S, was synthesized by the reaction of 6,7-dimethoxyhomophthalic anhydride with thiophene-2-carbaldehyde in the presence of 4-(dimethylamino)pyridine (DMAP) as a basic catalyst. The thiophene ring of the title molecule is disordered over two sites with occupancies of 0.877 (3) and 0.123 (3). The disorder corresponds to an approximate 180° rotation of the thiophene ring with respect to the C—C bond linking it to the rest of the molecule. The six-membered ring of the 3,4-dihydroisochromanone ring system is not planar [puckering parameters QT = 0.571 (2) Å, θ = 115.2 (2)° and ϕ = 99.1 (2)°]. The benzene ring of the 3,4-dihydroisochromanone ring system makes dihedral angles of 75.0 (2) and 77.2 (5)° with the disordered thiophene rings. Intermolecular O—H...O and C—H...O hydrogen bonds, as well as C—H...π interactions, lead to the observed supramolecular structure.