26645-09-0

Upstream product

• 66696-84-2 5-(1-hydroxy-2-phenylethylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione 
• 100-63-0 phenylhydrazine 
• 718-08-1 ethyl 3-oxo-4-phenylbutyrate 
• 103-80-0 phenylacetyl chloride 

Downstream Products

• 221641-16-3 3-benzyl-5-chloro-4-formyl-1-phenylpyrazole 
• 221641-27-6 5-azido-3-benzyl-4-formyl-1-phenylpyrazole 

Relevant academic research and scientific papers

New series of antiprion compounds: Pyrazolone derivatives have the potent activity of inhibiting protease-resistant prion protein accumulation

To find effective antiprion compounds, we synthesized and evaluated various pyrazolone derivatives. Seven of 19 compounds showed inhibition of PrP-res accumulation and the remarkably active compound 13 showed an IC50 value of 3 nM in both ScN2a and F3 cell lines. Findings from studies on physicochemical and biochemical properties suggest that the action mechanism of these compounds does not correlate with any antioxidant activities, any of hydroxyl radical scavenging activities, or any SOD-like activities.

Hydroxyl radical scavenging by edaravone derivatives: Efficient scavenging by 3-methyl-1-(pyridin-2-yl)-5-pyrazolone with an intramolecular base

We synthesized various 3-methyl-1-phenyl-5-pyrazolone (edaravone) derivatives and evaluated their oxidation potential and hydroxyl radical scavenging activity. It was found 3-methyl-1-(pyridin-2-yl)-5-pyrazolone had a much higher ability to scavenge the radical than did edaravone itself. Its efficient radical scavenging activity was assumed to be due to the increase of its anion form, an active form, by a hydrogen-bonded intramolecular base.

Solid-phase synthesis of substituted pyrazolones from polymer-bound β-keto esters

Polymer-bound acetoacetate 3 was γ-mono- and γ-dialkylated, as well as α-monoalkylated, to give 6, 9, and 13, respectively. Treatment with hydrazine or substituted hydrazines followed by thermal or acidic cyclizing cleavage yielded the pyrazolones 17a-dd in a purity of >90%.

A pyrazole to furan rearrangement. Thermolysis of 5-Azido-4-formylpyrazoles

5-Azido-3-benzyl-4-formyl-1-phenylpyrazoles 1a-c extrude dinitrogen upon heating in toluene to give the corresponding nitrenes, which immediately rearrange via a new ring-opening ring-closure reaction to produce an equimolar mixture of 4-cyano-2-phenyl-3-phenylazofurans 2a-c and 3-benzyl-4-cyano-1-phenylpyrazoles 3a-c. The formation of the 4-cyano-2-phenyl-3-phenylazofurans 2a-c is the first example in the pyrazole series of a nitrene rearrangement, in which the parent heterocyclic system of the product differs from that of the starting material. The isolation of equimolar amounts of the two products points to the fact that their formation occurs by two mechanistically interconnected pathways, between which the exchange of a redox equivalent takes place. Evidence for the existence of two mechanistically interlinked pathways is presented, and the insight into the stoechiometry of the reaction is taken advantage of to optimize the reaction with respect to either of the two products 2 or 3. Thus, it is demonstrated how one can bias the two pathways using external reagents, thereby changing the product distribution ratio 2:3 from 1:1 in the unbiased case, to 1:4 in one direction, and to better than 20:1 in the other direction.

Solid-phase synthesis of polymer-bound β-ketoesters and their application in the synthesis of structurally diverse pyrazolones

An efficient solid-phase synthesis of different polymer-bound β-ketoesters 7 is described using readily available acid chlorides 1 and haloalkanes 6 as building blocks. The corresponding pyrazolones 9 and 10 were obtained by mild acid catalyzed reaction with phenylhydrazine or by treatment with hydrazine under cyclisation and cleavage from the resin in high purity and good yield.