30152-32-0

Upstream product

• 57038-83-2 2-bromo-3-(4-chlorophenyl)-1-phenylprop-2-en-1-one 
• 22966-22-9 (E)-1-(4-chlorophenyl)-3-phenyl-2-propen-1-one 
• 104-88-1 4-chlorobenzaldehyde 
• 1576-35-8 toluene-4-sulfonic acid hydrazide 
• 19350-69-7 4-chlorobenzaldehyde p-toluenesulfonylhydrazone 
• 536-74-3 phenylacetylene 
• 102990-14-7 1-(4-chlorophenyl)-3-phenylprop-2-yn-1-ol 
• 16616-42-5 p-chlorobenzoylphenylacetylene 
• 122-01-0 4-chloro-benzoyl chloride 
• 956-04-7 3-(4-chlorophenyl)-1-phenylprop-2-en-1-one 
• 956-02-5 4'-chlorochalcone 
• 98-86-2 acetophenone 
• 4636-16-2 iodoacetophenone 
• 52372-80-2 (4-chlorobenzylidene)hydrazine 

Relevant academic research and scientific papers

Base promoted CuFe2O4 catalyzed one-pot synthesis of 3,5-diaryl-1H-pyrazoles

Available synthetic protocols for 3,5-diaryl-1H-pyrazoles generally demand long reaction time. Herein, we are reporting a CuFe2O4 catalyzed synthetic procedure for the same that delivers products in significantly reduced time starting from tosylhydrazones of aromatic aldehydes and terminal alkynes. Under the reaction condition, tosylhydrazone generates diazo compound in situ, which then undergoes [3 + 2] cycloaddition reaction with the terminal alkyne followed by [1,3]-H shift to deliver the final products in 72%–85% isolated yield. Magnetically active CuFe2O4 nanoparticles can be recovered very easily after the completion of the reaction and can be reused up to fifth cycle without significant loss in its catalytic activity. Operational simplicity of the methodology along with tolerability of various functional groups as well as easy recovery and high reusability of CuFe2O4 nanoparticles make the procedure a practical and handy one for the synthesis of 3,5-diaryl-1H-pyrazoles.

Fast and Efficient Continuous Flow Method for the Synthesis of Ynones and Pyrazoles

In this study, we developed a convenient and efficient two-step method for the synthesis of ynones in a flow reactor, through the generation of lithium acetylide and its subsequent reactions with acid chlorides. Using this approach, we obtained the ynones in moderate to good yields at room temperature. Moreover, we transformed the ynones into pyrazole derivatives through coupling with hydrazines. This transition metal-free process, mild reaction conditions, and broad functional group tolerance are all attractive features in comparison with conventional bench-top methods.

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

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.

Copper-Promoted Oxidative Intramolecular C–H Amination of Hydrazones to Synthesize 1H-Indazoles and 1H-Pyrazoles Using a Cleavable Directing Group

A facile and efficient synthesis of 1H-indazoles and 1H-pyrazoles through a copper-promoted oxidative intramolecular C–H amination of hydrazones using a cleavable directing group was developed. This reaction is characterized by its mild conditions, operational simplicity, readily available reagents, and excellent yields. A tentative mechanism for Cu-mediated C–H oxidative amination was proposed.

Sunlight-promoted Direct Irradiation of N-centred Anion: The Photocatalyst-free Synthesis of Pyrazoles in Water

A practical method through sunlight mediated annulation of α,β-unsaturated hydrazones has been developed for the synthesis of pyrazole. Based on the analysis of UV-Vis absorption of the substrate, the reaction was designed to avoid the use of external photocatalysis and proceeds via direct irradiation of N-centred anion by sunlight. The key features of this reaction include operational simplicity, readily available reagents, and amenability to gram-scale synthesis. (Figure presented.).

The diaza-Nazarov cyclization involving a 2,3-diaza-pentadienyl cation for the synthesis of polysubstituted pyrazoles

An unprecedented iodine-mediated diaza-Nazarov (DAN) type cyclization for the construction of substituted pyrazoles from easily available starting materials via an enamine-iminium ion intermediate is described. The oxidative cyclization worked under green conditions with remarkable regioselectivity. This one-pot, efficient and operationally simple three-component intramolecular regioselective DAN cyclization displayed a wide range of substrate scope. The dichotomy of reaction pathways has been explored with density functional theory in the gas phase and solution phase. Of the possible 1,5-, 1,6-, and 1,7-electrocyclizations, the DAN cyclization, i.e., the 1,5-pathway offers the lowest activation energy barrier supporting our experimental observations.

Transition Metal, Azide, and Oxidant-Free Homo- and Heterocoupling of Ambiphilic Tosylhydrazones to the Regioselective Triazoles and Pyrazoles

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

A highly efficient heterogeneous palladium-catalyzed cascade three-component reaction of acid chlorides, terminal alkynes and hydrazines leading to pyrazoles

In the presence of 0.5 mol% of 3-(2-aminoethylamino)propyl-functionalized MCM-41-immobilized palladium(II) complex [MCM-41-2N-Pd(OAc)2] and 1.0 mol% of CuI, acid chlorides were coupled with terminal alkynes in Et3N at 50 °C to give α,β-unsaturated ynones, which were converted in situ into pyrazoles by the cycloaddition of hydrazines at room temperature with acetonitrile as cosolvent. The cascade reactions generated a variety of pyrazole derivatives in moderate to good yields, and this heterogeneous palladium catalyst exhibited higher catalytic activity than PdCl2(PPh3)2 and could be recovered and reused for at least 10 consecutive trials without any decreases in activity.

A facile and expeditious approach to substituted 1H-pyrazoles catalyzed by iodine

A facile and expeditious method for the synthesis of 1H-pyrazoles by the reaction of α,β-unsaturated aldehydes/ketones and sulfonyl hydrazide catalyzed by as low as 2 mol % I2 has been demonstrated. This synthetic system features simple operation and mild reaction conditions, and displays a broad functional group tolerance furnishing good to excellent yields.

Synthesis of 3,5-disubstituted-1H-pyrazoles from acid chlorides, alkynes, and hydrazine in the presence of silica-supported-zinc bromide

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.