220637-92-3Relevant academic research and scientific papers
Peculiarities of copper(I)- and palladium-catalyzed cross-coupling of terminal alkynes with vicinal amino- and (N-acetylamino)-iodopyrazoles. Synthesis of alkynylaminopyrazoles
Tretyakov, Eugene V.,Knight, David W.,Vasilevsky, Sergei F.
, p. 3713 - 3720 (2007/10/03)
A number of vicinal amino- and (N-acetylamino)-alkylpyrazoles have been synthesized by cross-coupling reactions of iodopyrazoles with alk-1-ynes using a combination of Pd(PPh3)2Cl2 and CuI as catalyst in Et3N or with copper acetylides. The latter Stephens - Castro reaction of copper acetylides with these amino- and (N-acetylamino)-iodopyrazoles was established as a common method for the preparation of (N-acetylamino)alkynylpyrazoles. The Pd/Cu-catalyzed cross-coupling of iodopyrazoles (Sonogashira reaction) with alk-1-ynes bearing electron-releasing substituents was unsuitable for the synthesis of alkynylpyrazoles: 3- and 5-iodopyrazoles were unreactive but, in the case of 4-iodo derivatives, reductive deiodination, accompanied by homocoupling of the alk-1-yne component, was the only reaction. The Royal Society of Chemistry 1999.
