24979-47-3Relevant articles and documents
Polymer-supported acylhydrazones. Use in Sc(OTf)3-catalyzed mannich- type reactions providing an efficient method for the preparation of diverse pyrazolone derivatives
Kobayashi,Furuta,Sugita,Okitsu,Oyamada
, p. 1341 - 1344 (1999)
Polymer-supported acylhydrazones, prepared from polystyrene resin (1%divinylbenzene), reacted with ketene silyl acetals in the presence of a catalytic amount of scandium triflate (Sc(OTf)3), to afford the corresponding β-hydrazinoesters, which were cyclized and cleaved from the support simultaneously by treatment with a base to produce diverse pyrazolone derivatives.
Identification of Phenylpyrazolone Dimers as a New Class of Anti-Trypanosoma cruzi Agents
Sijm, Maarten,Siciliano de Araújo, Julianna,Ramos Llorca, Alba,Orrling, Kristina,Stiny, Lydia,Matheeussen, An,Maes, Louis,de Esch, Iwan J. P.,de Nazaré Correia Soeiro, Maria,Sterk, Geert Jan,Leurs, Rob
supporting information, p. 1662 - 1668 (2019/08/30)
Chagas disease is becoming a worldwide problem; it is currently estimated that over six million people are infected. The two drugs in current use, benznidazole and nifurtimox, require long treatment regimens, show limited efficacy in the chronic phase of infection, and are known to cause adverse effects. Phenotypic screening of an in-house library led to the identification of 2,2′-methylenebis(5-(4-bromophenyl)-4,4-dimethyl-2,4-dihydro-3H-pyrazol-3-one), a phenyldihydropyrazolone dimer, which shows an in vitro pIC50 value of 5.4 against Trypanosoma cruzi. Initial optimization was done by varying substituents of the phenyl ring, after which attempts were made to replace the phenyl ring. Finally, the linker between the dimer units was varied, ultimately leading to 2,2′-methylenebis(5-(3-bromo-4-methoxyphenyl)-4,4-dimethyl-2,4-dihydro-3H-pyrazol-3-one (NPD-0228) as the most potent analogue. NPD-0228 has an in vitro pIC50 value of 6.4 against intracellular amastigotes of T. cruzi and no apparent toxicity against the human MRC-5 cell line and murine cardiac cells.
Rare earth triflate-catalyzed addition reactions of acylhydrazones with silyl enolates. A facile synthesis of pyrazolone derivatives
Oyamada, Hidekazu,Kobayashi, Shu
, p. 249 - 250 (2007/10/03)
In the presence of a catalytic amount of a rare earth triflate, benzoylhydrazones reacted with silyl enolates to afford the corresponding β-N′-benzoylhydrazino esters in high yields. The hydrazino esters thus obtained were readily converted to pyrazolone derivatives by treatment with a base. A three-component reaction between an aldehyde, an acylhydrazine, and a silyl enolate was also performed successfully.
