Ozone mediated nitration of chlorobenzene with nitrogen dioxide over solid acid catalysts is expected to be a green process. The reaction was carried out at ca . 0 ℃. It was found that the solid acid catalysts of SO ...Ozone mediated nitration of chlorobenzene with nitrogen dioxide over solid acid catalysts is expected to be a green process. The reaction was carried out at ca . 0 ℃. It was found that the solid acid catalysts of SO 2- 4/TiO 2 and SO 2- 4/ZrO 2 and a series of SO 2- 4/TiO 2 ZrO 2 catalysts exhibited a fairly good activity for the nitration reaction, whereas SO 2- 4/TiO 2 ZrO 2(atomic ratio 1∶1) gives yield of 62 4% and SO 2- 4/TiO 2 ZrO 2(molar ratio 3∶1) shows a good para selectivity in CH 2Cl 2 solvent. The ortho para isomer ratios( ortho/para ) of the nitration products were varied in range from 1 11 to 0 36. This phenomenon is interpreted in terms of acid amount and acid strength of solid acid catalysts.展开更多
在采用区域选择性硝化方法合成β-硝基-5,10,15,20-四芳基卟啉铜、镍配合物的过程中,发现并通过核磁等方法分析了5,10,15,20-四(2-甲氧基苯基)卟啉及其相应β-硝基取代物的阻旋异构现象。图谱分析表明,与其结构类似的5,10,15,20-四(2-...在采用区域选择性硝化方法合成β-硝基-5,10,15,20-四芳基卟啉铜、镍配合物的过程中,发现并通过核磁等方法分析了5,10,15,20-四(2-甲氧基苯基)卟啉及其相应β-硝基取代物的阻旋异构现象。图谱分析表明,与其结构类似的5,10,15,20-四(2-羟基苯基)卟啉及5,10,15,20-四(4-甲氧基苯基)卟啉系列化合物没有该阻旋异构现象,说明邻位甲氧基阻碍了苯环与芳环之间C-C单键的旋转。进一步通过Chemdraw 3D Ultra软件能量最小化计算,讨论了阻转异构体可能的方式。展开更多
A visible light-mediated approach for the preparation of α-bromo-α,β-unsaturated ketones and aldehydes was developed. In comparison to traditional methods that generally take two steps to afford the above compounds...A visible light-mediated approach for the preparation of α-bromo-α,β-unsaturated ketones and aldehydes was developed. In comparison to traditional methods that generally take two steps to afford the above compounds, this protocol was highlighted by its operational simplicity, avoiding using hazardous bromine and mild reaction conditions.展开更多
文摘Ozone mediated nitration of chlorobenzene with nitrogen dioxide over solid acid catalysts is expected to be a green process. The reaction was carried out at ca . 0 ℃. It was found that the solid acid catalysts of SO 2- 4/TiO 2 and SO 2- 4/ZrO 2 and a series of SO 2- 4/TiO 2 ZrO 2 catalysts exhibited a fairly good activity for the nitration reaction, whereas SO 2- 4/TiO 2 ZrO 2(atomic ratio 1∶1) gives yield of 62 4% and SO 2- 4/TiO 2 ZrO 2(molar ratio 3∶1) shows a good para selectivity in CH 2Cl 2 solvent. The ortho para isomer ratios( ortho/para ) of the nitration products were varied in range from 1 11 to 0 36. This phenomenon is interpreted in terms of acid amount and acid strength of solid acid catalysts.
文摘在采用区域选择性硝化方法合成β-硝基-5,10,15,20-四芳基卟啉铜、镍配合物的过程中,发现并通过核磁等方法分析了5,10,15,20-四(2-甲氧基苯基)卟啉及其相应β-硝基取代物的阻旋异构现象。图谱分析表明,与其结构类似的5,10,15,20-四(2-羟基苯基)卟啉及5,10,15,20-四(4-甲氧基苯基)卟啉系列化合物没有该阻旋异构现象,说明邻位甲氧基阻碍了苯环与芳环之间C-C单键的旋转。进一步通过Chemdraw 3D Ultra软件能量最小化计算,讨论了阻转异构体可能的方式。
基金Acknowledgement The authors thank the National Natural Science Foundation of China （NNSFC） （Nos. 21072128, 21272153）, the Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry for financial support.
基金supported by the National Natural Science Foundation of China(2100201821072038+3 种基金2147203021302029)the State Key Laboratory of Urban Water Resource and Environment(2015DX01)the Fundamental Research Funds for the Central Universities(HIT.BRETIV.201310)
文摘A visible light-mediated approach for the preparation of α-bromo-α,β-unsaturated ketones and aldehydes was developed. In comparison to traditional methods that generally take two steps to afford the above compounds, this protocol was highlighted by its operational simplicity, avoiding using hazardous bromine and mild reaction conditions.
