Efficient Synthesis, Crystal Structure and Antibacterial Activity of Two Novel Thieno[2,3-d]pyrimidin-4(3H)-one Derivatives

Two new thieno[2,3-4pyrimidin-4(3B)-one derivatives, C24H22ClN3O2S (5a) and C25H25N3O2S (5b), have been synthesized via a tandem aza-Wittig reaction. This tandem reaction has many attractive aspects such as easily accessible and versatile starting materials, mild conditions and high yields. Both compounds have been characterized by elemental analysis, HR-MS, IR, NMR spectra and X-ray single-crystal diffraction. Compound 5a crystallizes in monoclinic, space group P2(1)/c with a = 9.986(3), b = 14.263(4), c = 15.530(5) angstrom, beta = 93.806(5)degrees, V = 2207.1(11) angstrom(3), M-r = 451.96, Z = 4, D-c = 1.360 g/cm(3), F(000) = 944, mu = 0.294 mm(-1), MoK alpha radiation (lambda = 0.71073 angstrom), the final R = 0.0444 and wR = 0.1219 for 3407 observed reflections with I > 2 sigma(I). Compound 5b crystallizes in triclinic, space group P (1) over bar with a = 8.974(4), b = 10.766(5), c = 12.260(6) angstrom, beta = 93.047(7)degrees, V = 1122.1(9) angstrom(3), M-r = 431.54, Z = 2, D-c = 1.277 g/cm(3), F(000) = 456, mu = 0.170 mm(-1), MoKa radiation (lambda = 0.71073 angstrom), the final R = 0.0378 and wR = 0.1072 for 3806 observed reflections with I > 2 sigma(I). The preliminary antibacterial activities of 5a and 5b were investigated. Compound 5a showed 71.3% and 79.2% in vitro inhibition against Fusarium oxysporium and Rhizoctonia solani, respectively. Compound 5b showed 75.3% in vitro inhibition against Rhizoctonia solani.