92133-95-4

Upstream product

• 1145-01-3 3,5-Diphenylpyrazole 
• 100-44-7 benzyl chloride 
• 536-74-3 phenylacetylene 
• 18440-50-1 N-benzyl-N'-benzylidene-4-methylbenzenesulfonohydrazide 
• 19816-85-4 N'-(1,2-diphenylethylidene)-4-methylbenzenesulfonohydrazide 
• 13466-30-3 (1-phenylethylidene)hydrazine 
• 98-86-2 acetophenone 
• 25229-59-8 Benzalacetophenon-p-tosylhydrazid 
• 100-39-0 benzyl bromide 
• 94-41-7 benzalacetophenone 
• 591-50-4 iodobenzene 
• 704873-40-5 1-benzyl-3,5-diphenyl-4,5-dihydro-1H-pyrazole 
• 108-86-1 bromobenzene 
• 100-42-5 styrene 

Relevant academic research and scientific papers

Bis(pyrazolyl)palladium(II) complexes as catalysts for Mizoroki–Heck cross-coupling reactions

Recent progress in carbon–carbon cross-coupling reactions has resulted in the discovery of highly active catalysts for carrying out such transformations. However, due to the wide array of applications of the products from cross-coupling reactions, there is the need to design suitable catalysts that permit the practical and economical synthesis of the cross-coupled products. Palladium complexes with bulky and electron-donating ligands have served as excellent (pre)catalysts for the Mizoroki–Heck cross-coupling reaction. By using bulky pyrazole-based ligands, we have prepared palladium(II) complexes with controlled steric and electronic properties of the metal center. We have used these bulky bis(pyrazolyl)palladium(II) complexes as (pre)catalysts for the Mizoroki–Heck cross-coupling reaction. The (pre)catalysts displayed high activity and selectivity, giving high catalytic conversions at a low (pre)catalyst loading and short reaction times. A mercury poisoning test confirmed that the (pre)catalysts promoted the Mizoroki–Heck cross-coupling homogenously and do not decompose into palladium black during the reactions. The catalytic systems were also tolerant to the presence of functional groups, such as 4-CF3, 4-CH3, 4-CO2Me and 4-CO2Et, on the alkene substrates.

Synthesis, characterization and evaluation of bulky bis(pyrazolyl)palladium complexes in Suzuki-Miyaura cross-coupling reactions

Pyrazole-containing compounds have been used in recent times as ligands to stabilize metal complexes used as pre-catalysts in cross-coupling reactions. With various substituents at various positions in the pyrazole ring, the overall electrophilic and steric properties of the metal complexes can be fine-tuned. Herein, we report the synthesis of bulky pyrazole-based ligands by condensation of methyl 4-(bromomethyl)benzoate or benzyl bromide with various substituted pyrazole compounds. These ligands were utilised in the synthesis of bis(pyrazolyl)palladium(ii) complexes. The complexes' catalytic activity in Suzuki-Miyaura cross-coupling reactions was evaluated. Phenyl bearing pre-catalyst 7, at a catalyst loading of 0.33 mol%, successfully converted 98% of bromobenzene and phenylboronic acid to biphenyl in 4 h at 140 °C, while the tertiary butyl bearing pre-catalyst 8 converted up to 81% of the same substrates to biphenyl. An increase in conversion was seen for all pre-catalysts when an electron-withdrawing substituent was present on the aryl halide substrate, and the opposite was observed when the electron-withdrawing group was present on the phenyl boronic acid.

Aluminum Chloride Mediated Reactions of N-Alkylated Tosylhydrazones and Terminal Alkynes: A Regioselective Approach to 1,3,5-Trisubstituted Pyrazoles

Aluminum chloride mediated reactions of N-alkylated tosylhydrazones and terminal alkynes are reported. The protocol is applied to a wide range of substrates, and demonstrates excellent functional group tolerance. A series of 1,3,5-trisubstituted pyrazoles is prepared in good to high yields with complete regioselectivity.

Regioselective one-step synthesis of pyrazoles from alkynes and N-tosylhydrazones: [3+2] dipolar cycloaddition/[1,5] sigmatropic rearrangement cascade

Rearrangement under control: A wide variety of 3,4,5- and 1,3,5-trisubstituted pyrazoles can be prepared from tosylhydrazones of ketones and terminal alkynes through the title reaction sequence (see scheme; Ts=4-toluenesulfonyl). The rearrangement, and th

Copper-Catalyzed aerobic intramolecular dehydrogenative cyclization of n,n-disubstituted hydrazones through C sp 3 -H functionalization

An aerobic activity: The title reaction proceeds through an oxidation/cyclization/aromatization sequence under an atmosphere of O 2 (see scheme; DBU=1,8-diazabicyclo[5.4.0]undec-7-ene, DCE=1,2-dichloroethane, DMS=dimethylsulfide). This coupling

Efficient one-pot synthesis of substituted pyrazoles

An efficient, one-pot synthesis of substituted pyrazoles from enones, hydrazides, and halides was developed. In comparison with the classical Knorr pyrazole synthesis, this methodology gave a different type of product (R 3≥R5). A range of substituted pyrazoles were prepared in good to high yields with complete regioselectivity.

A straightforward synthesis of pyrazolines and pyrazoles: Palladium-catalyzed carbonylative vinylation-cyclocondensation reactions of aryl halides

A novel consecutive one-pot synthesis of pyrazolines and pyrazoles starting from simple aryl halides, styrenes, carbon monoxide, and hydrazines has been established. Palladium-catalyzed carbonylative vinylation of aryl halides gave the corresponding chalcones, which are trapped in situ by addition of hydrazines.

Aminopyrazoles. V . Structure Assignment of 1H-Pyrazol-3- and 5-amines by Means of the 1H NMR δ(4-H)-Values of Their exo-N-Toluenesulfonyl Derivatives

From the extent of the low field chemical shift of 4-H caused by exo-N-tosylation of 1-substituted 1H-pyrazolamines it is possible to distinguish between the 3- and 5-amino-isomers.The pyrazole substituent increment system of Tensmeyer and Ainsworth has been extended to 3- and 5-amino, 3- and 5-tosylamino, 1-benzyl and 1-tosyl substituents.By comparison of δ(4-H) values, calculated with the aid of these increments, with measured δ(4-H) values, a differentiation between 3- and 5-tosylaminopyrazoles but not between 3- and 5-aminopyrazoles can be made.