Synthesis and crystal structure of ethyl 2,7,7-trimethyl-4-(4′-methylphenyl)-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate in aqueous medium

The title compound (C22H27NO3) was obtained by the reaction of 4-methylbenzaldehyde, dimedone, ethyl acetoacetate and ammonium acetate in water in the presence of triethylbenzylammonium chloride (TEBA). The crystal is of orthorhombic, space group Pbcn with a = 18.242(2), b = 15.651 (1), c = 14.207(2) angstrom, V = 4056.15(64) angstrom(3), M-r = 353.45, Z = 8, D-c = 1.158 g/cm(3), mu = 0.076, lambda(MoK alpha) = 0.71073 angstrom and F(000) = 1520. The final R = 0.0453 and wR = 0.0436 for 1156 observed reflections with I > 2 sigma(I). X-ray analysis revealed that the pyridine ring is of boat conformation and the six-member ring fused with it adopts half-chair conformation.