16860-56-3

Upstream product

• 1774-66-9 3-(4-bromophenyl)-1-phenylprop-2-en-1-one 
• 1122-91-4 4-bromo-benzaldehyde 
• 98-86-2 acetophenone 
• 766-96-1 4-bromo-1-ethynylbenzene 
• 98-88-4 benzoyl chloride 
• 100-52-7 benzaldehyde 
• 100-63-0 phenylhydrazine 
• 99-73-0 para-bromophenacyl bromide 
• 588-64-7 (E)-1-benzylidene-2-phenylhydrazine 
• 2515-60-8 5-(4-bromophenyl)-1,3-diphenyl-4,5-dihydro-1H-pyrazole 

Relevant academic research and scientific papers

Microwave-promoted oxidation of 1,3,5-trisubstituted 4,5-dihydro-1H- pyrazoles by in-situ generation of NO+ and NO2+ respectively from sodium nitrite and sodium nitrate in acetic acid

(Chemical Equation Presented) Microwave-assisted aromatization of 1,3,5-trisubstituted 4,5-dihydro-1H-pyrazoles by in-situ generation of NO + and NO2+ respectively from sodium nitrite and sodium nitrate in acetic acid has

Tricholoroisocyanuric acid as a useful reagent in microwave-assisted aromatization of 1,3,5-trisubstituted 2-pyrazolines

An efficient aromatization of 1,3,5-trisubstituted 2-pyrazolines to their corresponding pyrazoles has been performed by tricholoroisocyanuric acid [TCCA] under microwave irradiation in excellent yields. It has been observed that the reactions occur more r

Silica sulfuric acid-activated poly-1,3-dichloro-5methyl-5-(4'-vinylphenyl)hydantoin (PDCVH) as an effective reagent for oxidation of 1,3,5-trisubstituted 2-pyrazolines both under microwave irradiation and thermal conditions

Oxidation of 1,3,5-trisubstituted 4,5-dihydro-1H-pyrazoles to the corresponding pyrazoles has been achieved by utilizing silica sulfuric acidactivated poly-1,3-dichloro-5-methyl-5(4'-vinylphenyl)hydantoin in EtOH under both microwave irradiation and conve

Microwave-assisted aromatization of 1,3,5-trisubstituted 2-pyrazolines by Bi(NO3)3 · 5H2O, as a novel and convenient oxidizing agent

Bismuth(III) nitrate pentahydrate, Bi(NO3)3 · 5H2O, has been used as a mild, efficient, and inexpensive oxidant for the oxidative aromatization of several 1,3,5-trisubstituted 2-pyrazolines to pyrazoles in acetic acid unde

Cycloaddition of Nitrile Imines with Enamides: An Approach to Functionalized Pyrazolines and Pyrazoles

An efficient [3 + 2] cycloaddition of in situ generated nitrile imines with enamides has been established. A wide range of functionalized pyrazoline derivatives (53 examples) were obtained in moderate to good yields (up to 96%) under very mild conditions. This protocol features broad substrate scope, good functional group tolerance, and operational simplicity. Practical transformation of the products into useful pyrazoles via a one-pot process and the scalability of this protocol highlight the utility of this synthetic methodology.

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.

Visible light mediated metal-free oxidative aromatization of 1,3,5-trisubstituted pyrazolines

The visible light mediated oxidation of 1,3,5-trisubstituted pyrazolines under metal-free conditions was developed. Various substituted pyrazolines were oxidized to pyrazoles by irradiation with visible light/sunlight. A plausible mechanism was proposed f

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.

Molecular iodine: A green and inclusive catalyst for the synthesis of highly functionalized 1,3,5-trisubstituted pyrazoles in aqueous medium

A library of 1,3,5-trisubstituted pyrazoles was synthesized in excellent yields from the reaction of aldehyde, phenylhydrazine and alkynes in the presence of iodine via an eco-friendly, simple process performed in aqueous medium. This single pot transformation generates new CN, C-C, C-N bonds and proceeds by a domino reaction involving the formation of Schiff base, Mannich addition and finally intramolecular cyclisation. The Royal Society of Chemistry 2014.