7188-89-8

Upstream product

• 100-63-0 phenylhydrazine 
• 93-91-4 1-phenylbutan-1,3-dione 
• 557-98-2 2-chloropropene 
• 15424-14-3 N-phenylbenzohydrazonoyl chloride 
• 1817-57-8 4-phenyl-3-butyne-2-one 
• 15409-48-0 5-methyl-1,3-diphenyl-1H-pyrazole-4-carboxylic acid 
• 574-61-8 benzophenone N-phenylhydrazone 
• 75624-71-4 (E)-3-Methoxy-1-phenyl-4-(triphenyl-λ⁵-phosphanylidene)-but-2-en-1-one 
• 59-88-1 phenylhydrazine hydrochloride 
• 77252-92-7 (Z)-3-Ethoxy-1-phenyl-but-2-en-1-one 
• 75624-85-0 (1,3-Diphenyl-5-pyrazolylmethyl)triphenylphosphonium-chlorid 
• 369-57-3 benzenediazonium tetrafluoroborate 
• 495-40-9 propiophenone 
• 100-52-7 benzaldehyde 

Downstream Products

• 16492-49-2 5-methyl-1,3-diphenyl-4,5-dihydro-1H-pyrazole 

Relevant academic research and scientific papers

Regiocontrolled Coupling of Alkynes and Dipolar Reagents: Iron-Mediated [3 + 2] Cycloadditions Revisited

Cyclopentadienyliron dicarbonyl based allenyliron complexes were prepared, and their formal [3 + 2] cycloaddition with a number of dipolar reagents was investigated as a means of preparing heterocyclic compounds in a regiocontrolled manner. In addition, the mechanism of the isomerization of an allenyliron complex to its propargyliron tautomer was investigated. Results in support of both radical and two-electron mechanisms for isomerization are presented.

Visible-light enabled C4-thiocyanation of pyrazoles by graphite-phase carbon nitride (g-C3N4)

Thiocyanation is an important and effective way to form C[sbnd]S bonds in organic synthetic methodology. Especially, thiocyanation of pyrazole attracts the attention of many researchers because sulfur-containing compounds are widely applied in many crucial fields such as organic materials, agrochemistry, nanotechnology, etc. Herein, we described A rapid metal- and additive-free method for C(sp2)-H thiocyanation of pyrazoles under visible light at room temperature by using a sustainable catalyst of graphite-phase carbon nitride (g-C3N4) and a thiocyanating agent of ammonium thiocyanate. The method presents many advantages, such as usage of eco-friendly photoredox catalyst, a wide range of substrates and a good yield of products, etc.

Copper-Catalyzed Aerobic Cyclization of β,γ-Unsaturated Hydrazones with Concomitant CC Bond Cleavage

A Cu-catalyzed aerobic oxidative cyclization of β,γ-unsaturated hydrazones for the preparation of pyrazole derivatives has been developed. The hydrazonyl radical promoted the cyclization, along with a concomitant CC bond cleavage of β,γ-unsaturated hydrazones. This process has been verified via several control experiments, including a radical-trapping study, an 18O-labeling method, and the identification of the possible byproducts. The advantages of this reaction include operational simplicity, a broad reaction scope, and a mild selective reaction process.

Copper-Promoted Coupling of Propiophenones and Arylhydrazines for the Synthesis of 1,3-Diarylpyrazoles

Synthesis of 1,3-diarylpyrazoles from commercial substrates and/or simple transformations is still underrated. In this report, we have developed a method for copper-promoted coupling of propiophenones and arylhydrazines. The reactions afforded substituted pyrazoles in the presence of TEMPO oxidant, acetic acid additive, and DMF solvent. A number of functionalities were compatible with reaction conditions, including halogens, methoxy, trifluoromethyl, and nitro groups. An indazole could be obtained if an electron-poor propiophenone was used.

Facile synthesis of pyrazoles by iron-catalyzed regioselective cyclization of hydrazone and 1,2-diol under ligand-free conditions

A facile synthesis of pyrazoles by the cyclization of hydrazones and 1,2-diols was described. In the presence of ferric nitrate, the reaction occurs under neat conditions and makes the use of potassium persulfate to oxidize the diol to α-hydroxy carbaldehyde for the reaction with hydrazones to produce 1,3- and 1,3,5-substituted pyrazoles selectively. The overall regioselective transformation occurs in one-pot under ligand-free, mild conditions even in the presence of air.

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.

Nano-TiO2: An efficient and reusable catalyst for the synthesis of 1,3,5-substituted pyrazoles

(Formula presented) A Nano-TiO2 is an efficient catalysis for the synthesis of 1,3,5-substituted pyrazoles via condensation of 1,3- diketones and hydrazines. Simple procedure, mild heating, solvent free, high yielding, and easy workup are some advantages of this protocol. The catalyst can be recovered easily and reused many times without significant loss in catalytic activity and selectivity.

Csp3Csp3 bond cleavage in the palladium-catalyzed aminohydroxylation of allylic hydrazones using atmospheric oxygen as the sole oxidant

A C-C bond cleavage was observed in the palladium-catalyzed aminohydroxylation of allylic hydrazones, using atmospheric oxygen as the sole oxidant. This reaction could also proceed in a one-pot manner, starting from keto-alkene compounds and phenylhydrazine.

A modified and practical synthetic route to indazoles and pyrazoles using tungstate sulfuric acid

Tungstate sulfuric acid-catalyzed Knorr reaction have been used as a simple, rapid, atom economic and green method for the synthesis of indazole and pyrazole derivatives based on the condensation of hydrazine derivatives and ss-dicarbonyl compounds under solvent-free conditions. It was found that the catalyst could be recovered and reused without significant loss of its activity. The use of this method provides a novel and improved modification of Knorr synthesis in terms of clean reaction profile, use of a safe catalyst and solvent-free conditions. A green method for the synthesis of indazole and pyrazole derivatives from the condensation of hydrazine derivatives with dicarbonyl compounds has been described. Tungstate sulfuric acid (TSA) catalyzed efficiently the reactions to give good yields.

Cellulose sulfuric acid as a bio-supported and efficient solid acid catalyst for synthesis of pyrazoles in aqueous medium

A convenient and practical method was described for the regioselective synthesis of pyrazoles from hydrazines/hydrazides and 1,3-dicarbonyl compounds via the Knorr synthesis in water with cellulose sulfuric acid (CSA) as a biopolymer-based solid acid catalyst. Various hydrazines and hydrazides were reacted with 1,3 diketones and the desired pyrazoles were obtained in high yields. The reaction of less reactive hydrazines with 1,3-dicarbonyl compounds stopped at the corresponding hydrazone derivatives. Hydrazides were employed with β-ketoester, and imine adducts were the only isolated product. Simple isolation of products, mild reaction conditions, reusability of solid acid catalysts and short reaction times are advantages of this green procedure. This journal is