以间羟基苯甲酸为起始原料通过7步反应合成了15个新颖的N′-叔丁基-N′-取代苯甲酰基-N-(苯并二氢吡喃-5-甲酰基)肼类化合物.中间体3-炔丙氧基苯甲酸甲酯在N,N-二乙基苯胺中发生克莱森重排后得到主要产物苯并吡喃-5-甲酸甲酯和副产物苯并吡喃-7-甲酸甲酯.通过氢谱、元素分析或高分辨质谱确定了这些化合物的结构,化合物1a的X射线单晶衍射分析发现苯并二氢吡喃的吡喃环与苯环不共平面,其中的CO)和C(2)分别位于相应苯环平面的两侧.
Fifteen new N′-tert-butyl-N′-(substituted benzoyl)-N-(chromane-5-carbonyl)hydrazine derivatives were synthesized from 3-hydroxybenzoic acid. The intermediate methyl 3-(prop-2-ynyloxy)benzoate was refluxed in N,N-diethylaniline to give methyl 2H-chromene-5-carboxylate as main product and methyl 2H-chromene-7-carboxylate as byproduct. The structures of the target compounds were confirmed by ^1H NMR spectra, elemental analysis or high resolution mass spectra (HRMS). X-ray diffraction analysis of the target compound la shows that the pyran and the benzene rings of the chroman are not coplanar, and the C(1) and C(2) are at both sides of the plane of the corresponding benzene ring.