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].
Tandem Intermolecular–Intramolecular Michael Addition of Bifunctional Hetero Nucleophiles to Polyfluoro-2-alkynoic Acids. Facile Synthesis of Polyfluoroalkylated Azaheterocycles
Polyfluoro-2-alkynoic acids, Rf–C≡C–COOH (1a—c: a, Rf = CHF2; b, Rf = CF3; c, Rf = CHF2CF2CF2), readily underwent an intermolecular–intramolecular Michael addition reaction with a variety of bifunctional azanucleophiles, such as RNHCH2CH2XH (R = H, Me; X = NH, S, O, NMe) and o-phenylenediamine, to give the corresponding carboxylated and/or decarboxylated 2-(polyfluoroalkyl)imidazolidine, thiazolidine
Synthesis of trifluoromethyl-imines by solid acid/superacid catalyzed microwave assisted approach
作者:Mohammed Abid、Markku Savolainen、Shainaz Landge、Jinbo Hu、G.K. Surya Prakash、George A. Olah、Béla Török
DOI:10.1016/j.jfluchem.2007.01.011
日期:2007.6
deactivated substrates includes the use of a pressure vessel at 175 degrees C temperature, with solidsuperacidcatalysis. Using the solid acid K-10 montmorillonite or the superacidic perfluorinated resinsulfonic acid Nafion-H, a wide variety of trifluoromethylated imines have been synthesized using the above methods. The products have been isolated in good to excellent yields and high selectivities. This
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。