150433-19-5

Upstream product

• 19350-73-3 4-methyl-N'-(naphthalen-1-ylmethylene)benzenesulfonohydrazide 
• 75-20-7 calcium carbide 
• 90-11-9 1-Bromonaphthalene 
• 133228-21-4 N,N-dimethyl-1H-pyrazole-1-sulfonamide 
• 145799-89-9 (E)-3-(dimethylamino)-1-(naphthalen-1-yl)prop-2-en-1-one 
• 941-98-0 1'-naphthacetophenone 

Relevant academic research and scientific papers

Trinuclear diamagnetic nickel(II) complexes with bridging 3-arylpyrazolato ligands

Orange-red trinuclear nickel(II) complexes are obtained by reacting Ni(ClO4)2(H2O)6 with 3(5)-arylpyrazoles in the presence of a base. Herein, the diamagnetic nickel centers are coordinated in a square-pyramidal manner by four pyrazolato ligands, each of which bridges two nickel sites. The structurally unique complexes were investigated by NMR, IR, fluorescence, and X-ray spectroscopy. All seven compounds described here were structurally elucidated by single-crystal X-ray diffraction. With 3(5)-ferrocenylpyrazole as the substrate, a nonametallic system that possesses six redox-active ferrocenyl moieties was obtained. The reactions of Ni(ClO4)2(H2O)6 with 3(5)-arylpyrazoles in the presence of a base lead to pyrazolate-bridged trinuclear nickel(II) complexes. This strategy allows the introduction of a broad variety of aromatic substituents such as redox-active sites or additional phosphine donors in the periphery of the trinuclear core. Copyright

Calcium carbide as the acetylide source: Transition-metal-free synthesis of substituted pyrazoles via [1,5]-sigmatropic rearrangements

Under transition-metal-free conditions, calcium carbide was used as the acetylide source to react with a wide range of N-tosylhydrazones derived from aldehydes or ketones, affording various substituted pyrazoles in good yields with high regioselectivities. The transformations go through [3 + 2] cycloadditions followed by [1,5]-sigmatropic rearrangements, which are supported by deuterium-labeling experiments.

Selective palladium-catalyzed direct C-H arylation of unsubstituted N-protected pyrazoles

A highly selective C-5 arylation of N-dimethylaminosulfamoyl-protected pyrazole with aryl bromides is catalyzed by 2-5 mol% palladium in the presence of triphenylphosphine ligand and carboxylic acid additive. Selectivities up to 45:1 (C-5:C-4) can be achieved by running the reaction in non-polar solvents. A thorough study of scope and limitations shows good general tolerance of aryl bromide substitution. However, limitations on tolerance of ortho-subsitution and protic functional groups were established. Together with a telescoped deprotection step this method presents a viable alternative for the synthesis of C-3 arylated pyrazole building blocks.

Microwave assisted synthesis of 1-aryl-3-dimethylaminoprop-2-enones: A simple and rapid access to 3(5)-arylpyrazoles

Condensation of aromatic acyl compounds with N,N-dimethylformamide diethyl acetal in a pressure tube under microwave heating gives 1-aryl-3-dimethylaminoprop-2-enones in almost quantitative yields. In the presence of hydrazine, these intermediates are transferred to the corresponding 3-arylpyrazoles.