Synthesis, Crystal Structure and Biological Activity of Diethyl 1,4-dihydro-2,6-dimethyl-4-(4-methyl-1,2,3-thiadi azol-5-yl)pyridine-3,5-dicarboxylate

The title compound diethyl 1,4-dihydro-2,6-dimethyl-4-(4-methyl-1,2,3-thiadiazol-5-yl) pyridine-3,5-dicarboxylate(C16H21N3O4S, Mr = 351.42) was prepared by the Hantszch reaction with 4-methyl-1,2,3-thiadiazole-5-formaldehyde, ethyl acetoacetate and ammonium acetate in the presence of aluminum chloride in alcohol, and its structure was characterized by IR spectra, 1H-NMR, EA, and single-crystal X-ray diffraction. The crystal of the title compound belongs to monoclinic system, space group P21/n with a = 11.300(2), b = 12.771(3), c = 12.826(3) ?, β = 96.55(3)o, V = 1839.0(6) ?3, Z = 4, Dc = 1.296 g/cm3, μ(MoKa) = 0.71073 mm-1, F(000) = 744, R = 0.0981 and wR = 0.1994. X-ray diffraction result shows that the torsion angles of N(1)–C(2)– C(3)–C(4) and C(2)–C(3)–C(4)–C(8) are 178.9(3)° and –130.3(3)°, respectively. All rings in the title compound are non-planar. The bioassay results indicate that the title compound has good fungicidal activity, good antivirus activity against tobacco mosaic virus and certain extent of insecticidal activity against Mythimna separata.