37845-36-6Relevant articles and documents
Reactivity of Cross-Conjugated Enynones in Cyclocondensations with Hydrazines: Synthesis of Pyrazoles and Pyrazolines
Golovanov, Alexander A.,Odin, Ivan S.,Gusev, Dmitry M.,Vologzhanina, Anna V.,Sosnin, Ilya M.,Grabovskiy, Stanislav A.
, p. 7229 - 7241 (2021)
The cyclocondensation of cross-conjugated enynones, dienynones, and trienynones (easily available due to low-cost starting compounds) with arylhydrazines leads to the regioselective synthesis of pyrazole derivatives (dihetaryl-substituted ethens, buta-1,3-diens, and hexa-1,3,5-triens) or results in 4,5-dihydro-1H-pyrazoles in good yield. The reaction path is controlled by the character of the substituent in enynone: the pyrazoles are obtained from the reaction of substrates that contain five-membered heteroaromatic substituents with arylhydrazines, and the 4,5-dihydro-1H-pyrazoles are obtained from the reaction of 1,5-diphenylpent-1-en-4-yn-3-one with arylhydrazines consistently. Despite the presence of a substituent, cyclocondensation of 2-hydrazinylpyridine with all of examined cross-conjugated enynones leads to the formation of pyrazoles. The reaction does not require special conditions (temperature, catalyst, inert atmosphere). The cyclocondensation pathways are determined by the electronic effect of an electron-rich five-membered heteroaromatic ring in the substrate. The synthesis allows use of various substituents and functional groups in enynone and hydrazine. The present method features high yields and simplicity of the product purification. The obtained pyrazoles possess fluorescent properties with a quantum yield up to 31%.
One-Pot Synthesis of Symmetrical and Asymmetrical 3-Amino Diynes via Cu(I)-Catalyzed Reaction of Enaminones with Terminal Alkynes
Zhang, Changyuan,Guo, Huosheng,Chen, Lulu,Zhang, Jiantao,Guo, Mengping,Zhu, Xuncheng,Shen, Chan,Li, Zeng
, p. 8169 - 8173 (2021/11/01)
An economical and efficient protocol for the direct construction of amino skipped diynes through the Cu(I)-catalyzed reaction of enaminones and terminal alkynes has been described. Different kinds of symmetrical and asymmetrical 3-amino diynes could be ob
Synthesis of (: Z)-β-halo α,β-unsaturated carbonyl systems via the combination of halotrimethylsilane and tetrafluoroboric acid
Da Silva, Vitor A. F.,Da Silva, Gustavo P.,Matsuo, Bianca T.,Ali, Akbar,Davis, Rebecca L.,Zukerman-Schpector, Julio,Corrêa, Arlene G.,Paix?o, Márcio W.
supporting information, p. 519 - 526 (2019/01/24)
A convenient and broadly applicable method for the hydrohalogenation of ynones is described, by the combination of halotrimethylsilanes and tetrafluoroboric acid. Practically, one equivalent of HX (Br?nsted acid) and BF3 (Lewis acid) is smoothly generated, which activates the carbonyl compounds. Through this protocol, 42 examples of (Z)-β-halovinyl carbonyl compounds (Cl, Br and I) were obtained, in good yields and high stereoselectivity having 2-MeTHF as a solvent.
