4-Hy-droxy-5-meth-oxy-N,1-dimethyl-2-oxo-N-[4-(tri-fluoro-meth-yl)phen-yl]-1,2-di-hydro-quinoline-3-carboxamide.

The title compound, C20H17F3N2O4, named tasquinimod, is a second-generation oral quinoline-3-carboxamide analogue, which is currently in phase III clinical trials for the treatment of metastatic prostate cancer. The quinoline unit is almost planar (r.m.s. deviation of fitted atoms = 0.0075 Å). The carboxamide side chain, substituted at position 3, is tilted by 88.07 (7)° to the quinoline plane. Both the methyl and carbonyl groups of this carboxamide side chain are in a syn conformation. The 4-(tri-fluoro-meth-yl)phenyl plane is inclined at 50.62 (17)° to the plane of the carboxamide side chain, and at 87.14 (4)° to the plane of the quinoline ring system. The 4-hy-droxy H atom acts as a double proton donor in an intra-molecular hydrogen bond to the 5-position meth-oxy O atom and in an inter-molecular contact to the 2-oxo group, generating a chain along [010] in the crystal structure.