Experimental

R factor = 0.028; wR factor = 0.077; data-to-parameter ratio = 16.9. In the title compound, C21H21BrClNO4, the dihydropyridine ring adopts a flattened boat conformation. The 3-bromo-5-chloro-2-hydroxyphenyl ring forms a dihedral angles of 84.44 (7) with the dihydropyridine mean plane. The mol-ecular conformation is stabilized by an intramolecular O— H O hydrogen bond, with an S(8) ring motif. In the crystal, O—H O and C—H O hydrogen bonds link the molecules, forming a three-dimensional network. Related literature For the synthesis and bioactivity of acridines, see, for example: Karolak-Wojciechowska et al. (1996). For related structures, see: Abdelhamid et al. (2011a,b); Mohamed et al. (2012); Guo et al. (2004); Sughanya & Sureshbabu (2012); Yogavel et al