27301-76-4Relevant articles and documents
Unexpected ring opening of pyrazolines with activated alkynes: synthesis of 1H-pyrazole-4,5-dicarboxylates and chromenopyrazolecarboxylates
Bhimapaka, China Raju,Kolla, Sai Teja,Rayala, Nageswara Rao,Sridhar, Balasubramanian
supporting information, p. 334 - 338 (2022/01/20)
1H-Pyrazole-4,5-dicarboxylates and chromenopyrazole carboxylates were prepared by reacting pyrazolines with activated alkynes under neat conditions without a catalyst. The products were formed via unexpected ring opening of pyrazolines with the elimination of styrene/ethylene. These types of transformations are unknown and the products formed were confirmed using their spectral/analytical data. In addition, the structures of compounds 5e and 5n were confirmed by single-crystal X-ray analysis. Control experiments were conducted to support the proposed reaction mechanism.
Zinc-catalyzed synthesis of pyrazolines and pyrazoles via hydrohydrazination
Alex, Karolin,Tillack, Annegret,Schwarz, Nicolle,Beller, Matthias
supporting information; experimental part, p. 2377 - 2379 (2009/05/27)
(Chemical Equation Presented) A novel regioselective synthesis of aryl-substituted pyrazolines and pyrazoles has been developed. Substituted phenylhydrazines react with 3-butynol in the presence of a catalytic amount of zinc triflate to give pyrazoline derivatives. The resulting products are easily oxidized in a one-pot procedure to the corresponding pyrazoles.
