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-methylbenzal- dehyde, dimedone, ethyl acetoacetate and ammonium acetate in water in the presence of triethyl- benzylammonium chloride (TEBA). The crystal is of orthorhombic, space group Pbcn with a = 18.242(2), b = 15.651(1), c = 14.207(2) ?, V = 4056.15(64) ?3, Mr = 353.45, Z = 8, Dc = 1.158 g/cm3, μ = 0.076, λ(MoKα) = 0.71073 ? and F(000) = 1520. The final R = 0.0453 and wR = 0.0436 for 1156 observed reflections with I > 2σ(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.