Synthesis, crystal structures, and Hirshfeld analysis of three hexa-hydro-quinoline derivatives

Three hexa-hydro-quinoline derivatives were synthesized and crystallized in an effort to study the structure-activity relationships of these calcium-channel antagonists. The derivatives are ethyl 4-(2-meth-oxy-phen-yl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carboxyl-ate, C22H27NO4, (I), ethyl 4-(4-meth-oxy-phen-yl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carb-ox-yl-ate, C22H27NO4, (II), and ethyl 4-(3,4-di-hydroxy-phen-yl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexa-hydro-quinoline-3-carboxyl-ate, C21H24NO5, (III). In these hexa-hydro-quinoline derivatives, common structural features such as a flat-boat conformation of the 1,4-di-hydro-pyridine (1,4-DHP) ring, an envelope conformation of the fused cyclo-hexa-none ring, and a substituted phenyl group at the pseudo-axial position are retained. Hydrogen bonds are the main contributors to the packing of the mol-ecules in these crystals.

Crystal structure of ethyl 4-(3,4-dimethylphenyl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate, C23H29NO3

C23H29NO3, orthorhombic, Pbcn (no. 60), a = 18.781(7) Å, b = 15.749(6) Å, c = 14.081(5) Å, V = 4165(3) Å3, Z = 8, R gt(F) = 0.0614, wR ref(F 2) = 0.1874, T = 296(2) K.

Crystal structure of methyl 2-methyl-4-(3-methoxyphenyl)-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate, C19H21NO4

C19H21NO4, monoclinic, C2/c (no. 15), a = 17.349(5) Å, b = 7.354(2) Å, c = 25.757(7) Å, β = 97.637(5)°, V = 3257.1(16) Å3, Z = 8, R gt(F) = 0.0444, wR ref(F 2) = 0.1141, T = 296(2) K.

Crystal structure of ethyl 4-(3-chlorophenyl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate, C21H24ClNO3

C21H24ClNO3, orthorhombic, Pbcn (no. 60), a = 17.215(11) Å, b = 15.749(11) Å, c = 14.136(9) Å, V = 3832(4) Å3, Z = 8, R gt(F) = 0.058, wR ref(F 2) = 0.177, T = 296(2) K.