廉价的Keggin型多金属氧酸盐,即H 3 PW 12 O 40被发现是1,2-苯二胺和三氟甲基酮缩合环化反应以合成三氟甲基化杂环的有效催化剂,包括苯并咪唑啉,苯并恶唑啉和苯并噻唑啉。这项工作仅需要1 mol%的H 3 PW 12 O 40,并且质子和聚阴离子的协同作用对于反应至关重要。重要的是,通过使用双相溶剂体系(H 2 O /甲苯,V / V = 1:5)可以轻松回收POM催化剂,并至少重复使用四次而不会造成活性显着损失。
Efficient One-Pot Synthesis of Fluorinated Benzimidazolines, Benzothiazolines, Benzoxazolines, and Dihydrobenzoxazinones Using Gallium(III) Triflate as a Catalyst
作者:G. K. Surya Prakash、Thomas Mathew、Chiradeep Panja、Habiba Vaghoo、Karthik Venkataraman、George A. Olah
DOI:10.1021/ol062562e
日期:2007.1.1
One-pot synthesis of fluorinated benzimidazolines, benzothiazolines, benzoxazolines, and dihydrobenzoxazinones was easily achieved under mild conditions in high yields and purity through gallium(III) triflate mediated condensation-cyclization. Introduction of fluorine atoms favors the formation of the five-membered heterocycles over seven-membered heterocycles. [reaction: see text].
Nafion ® -H, a perfluoroalkanesulfonic acid resin, has been found to be a suitable solid acidcatalyst with high selectivity and catalytic activity for the one-potsynthesis of fluorinated benzimidazolines, benzothiazolines, benzoxazolines, and dihydrobenz-oxazinones. These Nafion ® -H mediated condensation-cyclization reactions were easily achieved under mild conditions in high yields and purity.
One-pot synthesis of trifluoromethylated benzimidazolines catalyzed by phosphotungstic acid with a low catalyst loading
作者:Xue Feng、Tao Yang、Xing He、Bing Yu、Chang-Wen Hu
DOI:10.1002/aoc.4314
日期:2018.5
an effect catalyst for the condensation‐cyclization reaction of 1,2‐phenylenediamines and trifluoromethyl ketones to synthesize trifluoromethylated heterocycles, including benzimidazolines, benzoxazolines and benzothiazolines. Only 1 mol% of H3PW12O40 was required in this work, and the synergistic effect of proton and polyanion was vital for the reaction. Significantly, the POM catalyst could be easily
廉价的Keggin型多金属氧酸盐,即H 3 PW 12 O 40被发现是1,2-苯二胺和三氟甲基酮缩合环化反应以合成三氟甲基化杂环的有效催化剂,包括苯并咪唑啉,苯并恶唑啉和苯并噻唑啉。这项工作仅需要1 mol%的H 3 PW 12 O 40,并且质子和聚阴离子的协同作用对于反应至关重要。重要的是,通过使用双相溶剂体系(H 2 O /甲苯,V / V = 1:5)可以轻松回收POM催化剂,并至少重复使用四次而不会造成活性显着损失。