Efficient Synthesis, Crystal Structure and Antibacterial Activity of Two Novel 1,3-Oxazin Derivatives

摘要

Two new 1,3-oxazin derivatives, C22H24N2O5(3I) and C19H16N2O5(3II), have been synthesized via an unusual cascade reaction. The attractive aspect of this cascade reaction is that the novel construction of 1,3-oxazine and the direct C-N bond formation from C-C bond can be easily achieved via pyridine-mediated acylation in a one-pot operation. Both compounds have been synthesized and characterized by elemental analysis, IR, NMR spectra and X-ray single-crystal diffraction. Compound 3I crystallizes in monoclinic, space group P21/n with a = 16.282(4), b = 7.4117(18), c = 17.256(5) , β = 103.193(9)°, V = 2027.4(9) 3, Mr = 396.43, Z = 4, Dc = 1.299 g/cm3, F(000) = 840, MoKa radiation(λ = 0.71073 ), the final R = 0.0771 and wR = 0.1582 for 3662 were observed reflections with I > 2σ(I). Compound 3II crystallizes in triclinic, space group P1 with a = 7.1265(9), b = 10.1071(13), c = 23.529(3), α = 97.463(9), β = 96.981(9), γ = 94.345(9)°, V = 1600.5(4) 3, Z = 4, Dc = 1.409 g/cm3, F(000) = 736, CuKa radiation(λ = 1.54186 ), the final R = 0.0515 and wR = 0.1241 for 4920 observed reflections with I > 2σ(I). The preliminary antibacterial activities of 2 and 3 against E. coli and S. aureus were investigated. The results showed that the inhibiting effect of 3 was higher than that of 2.