16901-34-1

Upstream product

• 19429-34-6 3-(4-bromophenyl)-1,5-diphenyl-2-pyrazoline 
• 766-96-1 4-bromo-1-ethynylbenzene 
• 201230-82-2 carbon monoxide 
• 59-88-1 phenylhydrazine hydrochloride 
• 2403-27-2 1-(4-bromophenyl)-3-phenyl-2-propen-1-one 
• 99-90-1 para-bromoacetophenone 
• 100-52-7 benzaldehyde 
• 16917-42-3 4-bromobenzaldehyde phenylhydrazone 
• 70-11-1 α-bromoacetophenone 
• 72758-69-1 (E)-1-(4-bromophenyl)-3-phenylprop-2-en-1-one 
• 100-63-0 phenylhydrazine 
• 25939-12-2 4-bromo-N-phenylbenzohydrazonoyl chloride 
• 124887-57-6 Bis-2,2,2-trifluoroethyl 1-phenylethenylphosphite 
• 81018-86-2 1-Phenylethenylphosphorous acid dibromide 

Relevant academic research and scientific papers

Hypervalent iodine oxidation of 1,3,5-trisubstituted pyrazolines: A facile synthesis of 1,3,5-trisubstituted pyrazoles

1,3,5-Trisubstituted pyrazolines (1a-i) undergo facile oxidation to the corresponding pyrazoles (2a-i) in the presence of iodobenzene diacetate.

PEROVSKITES FOR PHOTOCATALYTIC ORGANIC SYNTHESIS

Nature is capable of storing solar energy in chemical bonds via photosynthesis through a series of C—C, C—O and C—N bond-forming reactions starting from CO2 and light. Direct capture of solar energy for organic synthesis is a promising approach

Method for efficiently preparing 1,3,5-trisubstituted pyrazole compound

The invention discloses a method for efficiently preparing a 1,3,5-trisubstituted pyrazole compound. According to the method for efficiently preparing the 1,3,5-trisubstituted pyrazole compound, with metal palladium as a catalyst and triethylamine as an additive, aryl hydrazide hydrochloride, terminal alkyne and carbon monoxide are used as raw materials and react with one another under a heated condition in the atmosphere of oxygen to obtain the 1,3,5-trisubstituted pyrazole compound; and the reaction formula is formula (1). The method for efficiently preparing the 1,3,5-trisubstituted pyrazole compound realizes a method for preparing the 1,3,5-trisubstituted pyrazole compound by using palladium-catalyzed one-pot multi-component cascade reaction; and the method for efficiently preparing the 1,3,5-trisubstituted pyrazole compound has the advantages of simplicity, feasibility, simply and easy obtaining of raw materials and wide application prospect.

A Regioselective Approach to Trisubstituted Pyrazoles via Palladium-Catalyzed Oxidative Sonogashira-Carbonylation of Arylhydrazines

A palladium-catalyzed oxidative carbonylation of arylhydrazines and alkynes with balloon pressure CO/O2 to afford trisubstituted pyrazoles in a one-pot manner has been developed. The formation of trisubstituted pyrazoles involves a sequential C-N bond cleavage, carbonylation, Sonogashira coupling, Michael addition, and intramolecular condensation cyclization tandem process. An unprecedented oxidative Sonogashira-carbonylation reaction of arylhydrazine plays a key role for such a facile approach to pyrazoles.

13C NMR spectroscopy of heterocycles: 1-phenyl-3-aryl/t-butyl-5-arylpyrazoles

A series of chalcones 1-12 were converted to pyrazolines (1Pi-12Pi) by reaction with phenylhydrazine followed by DDQ oxidation to produce the corresponding pyrazoles (1Pz-12Pz). Three 1-phenyl-3-t-butyl-5-arylpyrazoles (13Pz-15Pz) were synthesized using an analogous approach. Molecular modeling studies predicted the 5-aryl group of the pyrazoles for both series to have a torsion angle of 52°-54° whereas the 1-phenyl group was predicted to have 35°-37° torsion angles. The 3-aryl group was predicted to be essentially coplanar (-3°) with the pyrazole system in the first series. 13C NMR data for both series, 1Pz-12Pz and 13Pz-15Pz, were collected in DMSO-d6 at 50°C. A plot of the C4 chemical shifts for 1Pz-12Pz versus Hammet constants for 5-aryl substituents yielded a very good linear correlation (R2=0.96) with a slope of 1.5. The chemical shift data for C4 showed little or no dependence on 3-aryl substituents. The result for 13Pz-15Pz, despite only three points, was consistent with the first series results and yielded a ρ value of 2.0. Distal transmission of substituent effects (5-aryl groups) to C4 of the pyrazole system was reduced by roughly 50-60% of that of the analogous planar isoxazole system, but are not consistent with results for the similarly twisted 4-bromoisoxazoles.

Radical Addition of Hydrazones by α-Bromo Ketones to Prepare 1,3,5-Trisubstituted Pyrazoles via Visible Light Catalysis

A novel efficient tandem reaction of hydrazones and α-bromo ketones is reported for the preparation of 1,3,5-trisubstituted pyrazoles by visible light catalysis. In this system, the monosubstituted hydrazones show wonderful reaction activity with alkyl radicals, generated from α-bromo ketones. A radical addition followed by intramolecular cyclization affords the important pyrazole skeleton in good to excellent yields. This efficient strategy under mild conditions with wide group tolerance provides a potential approach to the 1,3,5-trisubstituted pyrazoles.

Regioselective synthesis of 1,3,5-trisubstituted pyrazoles

A new and a simple approach toward synthesis of 1,3,5-trisubstituted pyrazoles from chalcone arylhydrazones via oxidative cyclization has been achieved. 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone was successfully used as an oxidizing agent to give excellen