Elemental Sulfur and Dimethyl
Sulfoxide‐Promoted
Oxidative Cyclization of Trifluoroacetimidohydrazides with Methylhetarenes for the Synthesis of
3‐Hetaryl
‐5‐trifluoromethyl‐1,2,4‐triazoles
摘要:
Main observation and conclusionA metal‐free approach for the synthesis of 3‐hetaryl‐5‐trifluoromethyl‐1,2,4‐triazoles via sulfur/dimethyl sulfoxide‐promoted oxidative cyclization of readily available trifluoroacetimidohydrazides with methylhetarenes has been developed. This transformation proceeds in cascade sulfur‐mediated generation of thioaldehyde, condensation, intramolecular cyclization and oxidative aromatization sequence.
e annulation reaction for the efficient construction of 2-(trifluoromethyl)quinazolin-4(3H)-ones has been developed. This transformation employs readily available isatins and trifluoroacetimidoyl chlorides as the starting materials, providing a facile and practical route to diverse biologically relevant quinazolin-4(3H)-one derivatives. A plausible reaction pathway has been proposed based on the mechanistic
metal-free approach for the synthesis of 5-trifluoromethyl-1,2,4-triazoles via I2-mediated [4+1] annulation of readily available trifluoroacetimidohydrazides and methyl ketones has been achieved. The transformation involves iodination/Kornblum oxidation, intermolecular dehydration condensation and an iodine-mediated intramolecular cyclization/aromatization sequence. The developed protocol can be easily scaled
已经实现了一种通过 I 2介导的 [4+1] 环化容易获得的三氟乙酰氨基酰肼和甲基酮来合成 5-三氟甲基-1,2,4-三唑的无金属方法。该转化包括碘化/Kornblum 氧化、分子间脱水缩合和碘介导的分子内环化/芳香化序列。开发的协议可以很容易地扩展到 3 mmol 规模而不会明显降低效率,并且可以通过连续的一锅方式实施。
Base-mediated [3+2] annulation of trifluoroacetimidoyl chlorides and isocyanides: An improved approach for regioselective synthesis of 5-trifluoromethyl-imidazoles
作者:Sipei Hu、Hefei Yang、Zhengkai Chen、Xiao-Feng Wu
DOI:10.1016/j.tet.2020.131168
日期:2020.5
A t-BuOK-mediated [3 + 2] cycloaddition reaction of trifluoroacetimidoyl chlorides and active methylene isocyanides for the synthesis of 5-trifluoromethyl-imidazoles has been developed. Under mild reaction conditions, the transformation proceeds smoothly in the presence of t-BuOK to afford an array of structurally diverse 5-trifluoromethyl-imidazoles with high efficiency.
The cascade coupling/iodoaminocyclization reaction of trifluoroacetimidoyl chlorides and allylamines: metal-free access to 2-trifluoromethyl-imidazolines
coupling/iodoaminocyclization reaction for the rapid assembly of 2-trifluoromethyl-imidazolines has been disclosed. The transformation applies readily accessible trifluoroacetimidoyl chlorides, allylamines and N-iodosuccinimides as the starting substrates, achieving an efficient and straightforward pathway to construct diverse imidazoline derivatives. Excellent efficiency of the reaction is observed (higher
A silver-mediated [3 + 2] cycloaddition of azomethine ylides with trifluoroacetimidoyl chlorides for the rapid assembly of 5-(trifluoromethyl)imidazoles has been developed. Notable features of the reaction include readily accessible reagents, a broad substrate scope, and high efficiency. The protocol can be successfully applied to construct the analogue of the specific allosteric modulator of GABAA