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.

Abstract

This paper reports the X-ray crystal structure of tasquinimod (molecular formula C20H17F3N2O4), a second-generation orally administered quinoline-3-carboxamide analogue currently undergoing Phase III clinical evaluation in metastatic prostate cancer. The quinoline ring system is nearly planar, with a root-mean-square deviation of 0.0075 Å for fitted atoms. The carboxamide side chain at position 3 is tilted approximately 88.07° relative to the quinoline plane, with both the methyl and carbonyl groups adopting a syn conformation. The 4-(trifluoromethyl)phenyl ring is inclined at 50.62° to the carboxamide plane and at 87.14° to the quinoline ring system. The hydroxyl hydrogen at position 4 participates in both an intramolecular hydrogen bond directed toward the 5-methoxy oxygen and an intermolecular contact with the 2-oxo group, producing a chain motif along the [010] crystallographic direction.