【摘要】 报道了 Ti Cl4 -Sm体系引起的邻硝基苯甲酰胺与酮的反应 .研究发现 ,邻硝基苯甲酰胺与酮还原成环生成 1 ,2 -二氢喹唑啉 -4( 3 H) -酮 .产物的结构通过元素分析、IR、 1 H NMR谱和单晶 X射线衍射法确定更多还原

【Abstract】 This paper reports the reactions of o nitrobenzamides with ketones induced by titanium reagent(TiCl 4 Sm system). The results show that the low valent titanium promoted a novel reductive cyclization of o nitrobenzamides and ketones to give 1,2 dihydroquinazolin 4(3H) ones. The products were characterized by elementary analysis, IR, 1H NMR and X ray single crystal diffraction. The crystal of compound 3b belongs to monoclinic system with space group P2 1/n, a =1.191 7(2) nm, b =0.691 1(1) nm , c =1 782 1(4) nm, β=98.81°, V =1.455 04(5) nm 3, Z=4, D c=1.220 g/cm 3, μ =0.077 mm -1 , F (000)=568, and final R =0.043 3 and wR =0.107 6 for reflections [ I>2σ(I) ]. In summary, a series of 1,2 dihydroquinazolin 4(3H) ones was synthesized via reductive cyclization of o nitrobenzamides with ketones induced by the TiCl 4 Sm system. Our method possesses the advantages of easily accessible starting materials, convenient manipulation and moderate to high yield.更多还原