微波辐射下氯代苯胺基吡咯亚胺类化合物的合成及其晶体结构

Synthesis and the Crystal Structure of Chloroaniline Based Mono(imino)pyrroles under Microwave Irradiation

摘要:

将2-乙酰基吡咯作为前驱体与取代位置不同的芳香胺：邻氯苯胺、间氯苯胺、对氯苯胺在微波辐射下反应时发现，当氯原子（钝化基团）处于苯环的间位及对位时，芳香胺与2-乙酰基吡咯可成功发生希夫碱缩合反应得到吡咯亚胺化合物1a和1b；而当氯原子处于苯环邻位时，二者不发生反应。1a和1b的结构经X-射线单晶衍射，1H NMR，IR，MS和元素分析表征证实为预期化合物。X-射线单晶衍射测定结果表明，1a属单斜晶系，空间群C2/C，晶体参数a = 23.722 (15) Å，b = 5.720 (4) Å，c = 16.868 (11) Å，β = 98.404 (10)°，V = 2264 (3) Å3，Z = 8，Dc = 1.283 g·m-3，R1 = 0.0419，ωR2 = 0.1195。1b属单斜晶系，空间群P21/C，晶胞参数a = 13.323 (3) Å，b = 9.802 (2) Å，c = 9.107 (2) Å，β = 109.212 (4)°，V = 1123.1 (4) Å3，Z = 4，Dc =1.293 g·m-3，R1 = 0.0472，ωR2 = 0.1189。对芳香胺上钝化基团的位置对希夫碱缩合反应的影响也进行了初步探讨。

Abstract:

Using 2-acetylpyrrole and a couple of aromatic amines, such as 3-chloroaniline and 4-chloroaniline as the raw materials, two chloroaniline based mono(imino)pyrroles 2-{1-[(3-chlorophenyl)l)imino]ethyl}pyrrole (1a) and 2-{1-[(4-chlorophenyl)l)imino]ethyl} pyrrole (1b) were prepared under the microwave irradiation. No indication showed the reaction occurred between 2-acetylpyrrole and 2-chloroaniline. These structures were characterized by X-ray single crystal diffraction, 1H NMR, IR, MS and elemental analysis. 1a belongs to monoclinic system, space group C2/C with a = 23.722 (15) Å, b = 5.720 (4) Å, c = 16.868 (11) Å, β = 98.404 (10)°, V = 2264 (3) Å3, Z = 8, Dc = 1.283 g·m-3, R1 = 0.0419, ωR2 = 0.1195. 1b also belongs to monoclinic system, space group P21/C with a = 13.323 (3) Å, b = 9.802 (2) Å, c = 9.107 (2) Å, β = 109.212 (4)°, V = 1123.1 (4) Å3, Z = 4, Dc =1.293 g·m-3, R1 = 0.0472, ωR2 = 0.1189. Reaction mechanism between the position of deactivation group on the aromatic amines and the Schiff base condensation was also discussed.