A direct synthesis of β-carbolines via a three-step one-pot domino approach with a bifunctional Pd/C/K-10 catalyst

A rapid, microwave-assisted synthesis of β-carbolines via a successive condensation/cyclization/dehydrogenation approach is described. This methodology involves the coupling of various tryptamines with aromatic aldehydes/glyoxals. The product imine undergoes a Pictet-Spengler cyclization followed by a final dehydrogenation to yield β-carbolines in a three-step domino reaction. The use of the bifunctional catalyst Pd/C/K-10 combined with microwave irradiation enabled the synthesis of β-carbolines in short reaction times and in good to excellent yields.     

正丁烷在Au,Zn组合改性纳米HZSM-5上的催化转化

采用沉积沉淀和浸渍法制备了Au-Zn组合改性HZSM-5催化剂.并且对比研究了HZSM-5,Au/HZSM-5,Zn/HZSM-5和Au-Zn/HZSM-5催化剂的性质和催化性能.采用UV-Vis和XPS表征揭示出Au-Zn/HZSM-5催化剂中Au物种与Zn物种的相互作用.正丁烷探针反应结果表明,在Zn/HZSM-5催化剂中引入Au有效地提高了正丁烷的脱氢芳构化性能,同时抑制了正丁烷在Zn活性中心上的氢解副反应.在相同条件下,与Zn/HZSM-5催化剂相比,正丁烷转化率由49.1%增加到70.8%,烯烃和芳烃产物总选择性由57%增加到61.98%,干气的选择性由31%降低至28.4%.上述结果表明,Au-Zn/HZSM-5催化剂在轻烃芳构化反应中具有良好的催化性能.     

甲醇芳构化中催化剂酸性对脱烷基、烷基化和异构化反应的影响

在Zn/P/ZSM-5催化剂上研究了甲醇、二甲苯、甲苯和甲醇等不同进料下芳烃产品分布随反应积碳的变化, 发现催化剂积碳对芳构化反应、脱烷基反应和烷基化反应的影响不同. 在不同硅铝摩尔比(Si/Al 比)和Zn负载量的Zn/P/ZSM-5 催化剂上进行甲醇转化, 考察催化剂酸性位点强度、密度和类型与芳烃收率和产品分布之间的关系, 发现当强酸位点酸密度下降时, 脱烷基反应最先被抑制, 其次是芳构化反应和异构化反应, 而烷基化反应却不受影响. 在Si/Al 比为14, 3% (w) Zn 负载量的Zn/P/ZSM-5 催化剂上可得到75%左右的芳烃收率, 二甲苯收率在35%左右, 具有重要的工业应用前景.     

A short and efficient synthesis of honokiol via Claisen rearrangement

A concise and efficient total synthesis of honokiol, a biphenyl-type neolignan is accomplished in six steps using readily available and cost-effective reagents. The synthetic route involves mainly the Grignard reaction, iodine mediated aromatization, and Claisen rearrangement as key steps. A predominant formation of honokiol (1a) was observed in the Claisen rearrangement under microwave irradiation whereas the isohonokiol (1b) was formed as a major product under conventional conditions.     

TBPA＋ mediated aromatization of 1,3,5-trisubstituted pyrazolines

1,3,5-Trisubstituted pyrazolines were oxidized to the corresponding pyrazoles in high yield with tris（4-bromophenyl）aminium （TBPA＊＊） hexachloroantimonate in chloroform at room temperature.     

Deacylative Thiolation by Redox-Neutral Aromatization-Driven C−C Fragmentation of Ketones

Herein we report the development of deacylative thiolation of diverse methyl ketones. The reaction is redox-neutral, and heavy-metal-free, which provides a new way to introduce thioether groups site-specifically to unactivated aliphatic positions. It also features excellent functional group tolerance and broad substrate scope, thus allowing late-stage derivatization. The process benefits from efficient condensation between the activation reagent and ketone substrates, which triggers aromatization-driven C−C fragmentation and rapid radical coupling with thiosulfonates. Experimental and computational mechanistic studies suggest the involvement of a radical chain pathway.     

预处理条件对Mo/HZSM-5和Mo-Zn/HZSM-5甲烷芳构化性能的影响

甲烷无氧芳构化 ,具有选择性高、技术简单及产物易分离等特点 ,已引起人们的广泛关注 [1,2 ] .Mo/HZSM- 5是芳构化的良好催化剂 ,为了探讨预处理条件对反应的影响 ,我们对不同预处理条件下的 Mo/HZSM- 5及 Zn改性的 Mo/HZSM- 5催化剂上的甲烷无氧芳构化反应进行了研究 ,并以热重法对催化剂的稳定性进行了表征 .1实验部分1 .1原料和试剂钼酸铵 ( A.R.级 ) ,乙酸锌 ( A.R.级 ) ,铵型ZSM- 5分子筛 (硅铝比为 5 0～ 70 ) .1 .2催化剂制备铵型 ZSM- 5分子筛于 81 3K、空气气氛下焙烧3h,即成 HZSM- 5分子筛 .以一定浓度的钼酸铵溶液…