50603-96-8Relevant articles and documents
One-pot regioselective synthesis of substituted pyrazoles and isoxazoles in PEG-400/water medium by Cu-free nano-Pd catalyzed sequential acyl Sonogashira coupling-intramolecular cyclization
Thirukovela, Narasimha Swamy,Balaboina, Ramesh,Botla, Vinayak,Vadde, Ravinder,Jonnalagadda, Sreekantha Babu,Vasam, Chandra Sekhar
, p. 6471 - 6481 (2019/11/20)
Catalyst efficacy of in situ generated Pd-nanoparticles (PdNPs) in the regioselective one-pot synthesis of 3,5-di & 3,4,5-trisubstituted pyrazoles and 3,5-disubstituted isoxazoles in environmentally benign PEG-400/H2O medium, which involves the sequential (i) Cu-free acyl-Sonogashira coupling (ASC) and (ii) intramolecular ynone-amine cyclization under PTC conditions was described. The results of controlled experiments support the operation of two sequential catalytic cycles (ASC/cyclization) and achievement of complementary/opposite regioselectivity via ynone-bound palladium in a one-pot approach. Moreover, the in situ PdNPs recovered after the first catalytic cycle of the one-pot reaction sequence have been reused again five times successively. Besides, prior to the above studies, the efficacy of some common Pd-N-heterocyclic carbene (Pd-NHC) complexes in catalyzing the same one-pot two-step reaction sequence (Cu-free ASC/cyclization) both in water and organic solvents was also optimized. In situ generation of PdNPs from above Pd-NHCs in water was also identified, but they are not reusable due to their large size distribution.
Transition Metal, Azide, and Oxidant-Free Homo- and Heterocoupling of Ambiphilic Tosylhydrazones to the Regioselective Triazoles and Pyrazoles
Panda, Subhankar,Maity, Pradip,Manna, Debasis
, p. 1534 - 1537 (2017/04/13)
With N-tosylhydrazone as an ambiphilic reagent, an unprecedented cyclization reaction of two identical or different tosylhydrazones has been developed to access various 4,5-disubstituted-2H-triazoles under transition metal, azide, and oxidant-free conditi
Synthesis of 3,5-disubstituted-1H-pyrazoles from acid chlorides, alkynes, and hydrazine in the presence of silica-supported-zinc bromide
Keivanloo, Ali,Bakherad, Mohammad,Samangooei, Shahrzad
, p. 484 - 486 (2015/11/03)
An efficient one-pot palladium- And copper-free procedure has been developed for a convenient synthesis of 3,5-disubstituted-1H-pyrazoles from various acid chlorides, terminal alkynes and hydrazine by a coupling reaction and cyclocondensation sequence. Acid chlorides react with terminal alkynes in the presence of silica-supported-zinc bromide to give α,β-unsaturated ynones, and in situ conversion into pyrazoles by the hydrazine cyclocondensation.