- Visible-light enabled C4-thiocyanation of pyrazoles by graphite-phase carbon nitride (g-C3N4)
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Thiocyanation is an important and effective way to form C[sbnd]S bonds in organic synthetic methodology. Especially, thiocyanation of pyrazole attracts the attention of many researchers because sulfur-containing compounds are widely applied in many crucial fields such as organic materials, agrochemistry, nanotechnology, etc. Herein, we described A rapid metal- and additive-free method for C(sp2)-H thiocyanation of pyrazoles under visible light at room temperature by using a sustainable catalyst of graphite-phase carbon nitride (g-C3N4) and a thiocyanating agent of ammonium thiocyanate. The method presents many advantages, such as usage of eco-friendly photoredox catalyst, a wide range of substrates and a good yield of products, etc.
- Pan, Junyi,Liu, Cheng,Wang, Jianqiang,Dai, Yunqiao,Wang, Shengyu,Guo, Cheng
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supporting information
(2021/07/14)
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- Direct synthesis of pyrazoles from esters using tert-butoxide-assisted C-(C=O) coupling
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This paper describes the direct synthesis of pyrazoles from esters that comprises two sequential reactions: tert-butoxide-assisted C-C(=O) coupling reaction to yield β-ketonitrile or α,β-alkynone intermediates, and condensation by hydrazine addition. The method reported allows for easy control of the regioselectivity and structure of substituents at N-1, C-3, C-4 and/or C-5 positions.
- Kim, Bo Ram,Sung, Gi Hyeon,Ryu, Ki Eun,Lee, Sang-Gyeong,Yoon, Hyo Jae,Shin, Dong-Soo,Yoon, Yong-Jin
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supporting information
p. 9201 - 9204
(2015/06/08)
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- VILSMEIER-HAACK REACTION OF 5-AMINO- AND 5-ACYLAMINO-PYRAZOLES
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The Vilsmeier-Haack reaction of 5-aminopyrazole derivatives 1 was investigated in view of contradictory literature reports.Structure 2 of the products was proved both chemically and spectroscopically.The mechanism of the reaction was postulated on the basis of isolated intermediates 7 and 8. 5-Acylaminopyrazoles 9, 10 and 11 were found to give also 2 (and 7) under the Vilsmeier conditions by an acyl splitting reaction, proceeding probably via diacylamino derivatives 12.Compounds 2 provided a simple route to pyrazolopyrimidine derivatives 13 and 14 as well as to azomethine compounds 15-18.
- Simay, A.,Takacs, K.,Horvath, K.,Dvortsak, P.
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p. 127 - 140
(2007/10/02)
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