- Scale-Up of a Continuous Manufacturing Process of Edaravone
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Edaravone belongs to a class of brain-protective agents, which can scavenge free radicals. To reduce impurities and improve the yield, a continuous flow production process of edaravone was developed. The synthesis is continuously carried out in two steps. The throughput can reach 11.328 kg/day and the purity of the final product is 99.95%, which are in accordance with the needs of production. This is an efficient and quick production process suitable for industrial production.
- He, Yan,Hong, Qingxia,Mei, Wenliu,Sun, Tiemin,Wu, Chengjun,Zhou, Shuhao
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- Transformations of phenylhydrazones of dialkyl 2-oxo-propane-1,3- dicarboxylate and of ethyl acetoacetate in concentrated sulfuric acid
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The hydrazones 3a,b, prepared from phenylhydrazine (1) and dialkyl 2-oxopropane-1,3-dicarboxylate (2a,b) were converted in concentrated sulfuric acid at -5 °C into a mixture of alkyl (3-carboxyindol-2-yl)acetates (5a,b), and ethyl (5-ethoxy-1-phenyl-1H-pyrazol-3-yl)acetate 6. The hydrazone 8, prepared from 1 and ethyl acetoacetate (7) was transformed under the same conditions into a mixture of five compounds: ethyl 2-methylindol-3-carboxylate (9), 2-methylindol-3-carboxylic acid (10), 2-methylindol (11), 5-ethoxy-3-methyl-1-phenyl-1H-pyrazole (12), and 3-methyl-1-phenyl-1H-pyrazol-5- one (13).
- Bevk, David,Svete, Jurij,Stanovnik, Branko
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- ZnO: An Ecofriendly, Green Nano-catalyst for the Synthesis of Pyrazole Derivatives under Aqueous Media
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An efficient nano ZnO catalyzed green protocol for the synthesis of pyrazol derivatives by condensation of different substituted phenyl hydrazines/semicarbazide/thiosemicarbazide with 1,3-diketone/ketoester at ambient temperature has been achieved. ZnO na
- Girish, Yarabally R.,Kumar, Kothanahally S. Sharath,Manasa, Heggadihalli S.,Shashikanth, Sheena
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- 2 (Oxa) as a heterogeneous recyclable catalyst: Synthesis of pyrazoles under mild reaction conditions
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We developed a novel and highly efficient protocol for the synthesis of important pyrazole derivatives by using some 1,3-dicarbonyl compounds and phenyl hydrazines via a one-pot protocol. As a recyclable heterogeneous catalyst, we used [Ce(l-Pro)2]2 (Oxa). In addition, the catalyst is recyclable, the proline is economically viable and readily available in both enantiomeric forms and the catalyst is insoluble in almost all solvents and may be easily filtered off from the reaction medium. Moreover, this new synthetic protocol features high conversion, short reaction times, a straightforward procedure and cleaner reaction profiles.
- Katla, Ramesh,Chowrasia, Rakhi,Manjari, Padma S.,Da Silva, Caren D. G.,Dos Santos, Beatriz F.,Domingues, Nelson L. C.
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supporting information
p. 9471 - 9476
(2016/11/11)
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- Room-temperature synthesis of pyrazoles, diazepines, β-enaminones, and β-enamino esters using silica-supported sulfuric acid as a reusable catalyst under solvent-free conditions
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Silica-supported sulfuric acid (H2SO4·SiO2) has been utilized as a heterogeneous recyclable catalyst for a highly efficient regio- and chemoselective condensation of hydrazines/hydrazides, diamines, and primary amines with various β-dicarbonyl compounds at room temperature to afford pyrazoles, diazepines, and β-enaminones/β-enamino esters under solvent-free conditions within 5-15 min. Copyright Taylor & Francis Group, LLC.
- Chen, Xiang,She, Jin,Shang, Zhi-Cai,Wu, Jun,Zhang, Peizhi
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experimental part
p. 947 - 957
(2009/09/06)
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- Synthesis of pyrazoles, diazepines, enaminones, and enamino esters using 12-tungstophosphoric acid as a reusable catalyst in water
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12-Tungstophosphoric acid (H3PW12O40) is found to be an efficient and recyclable catalyst in promoting a chemo- and regioselective condensation of hydrazines/hydrazides, diamines, and primary amines with various 1,3-dicarbonyl compounds in pure water at room temperature to afford pyrazoles, diazepines, and enaminones/enamino esters, respectively, in high yields. Georg Thieme Verlag Stuttgart.
- Chen, Xiang,She, Jin,Shang, Zhicai,Wu, Jun,Wu, Haifeng,Zhang, Peizhi
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experimental part
p. 3478 - 3486
(2009/05/09)
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- Greener and rapid access to bio-active heterocycles: room temperature synthesis of pyrazoles and diazepines in aqueous medium
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An expeditious room temperature synthesis of pyrazoles and diazepines by condensation of hydrazines/hydrazides and diamines with various 1,3-diketones is described. This greener protocol was catalyzed by polystyrene supported sulfonic acid (PSSA) and proceeded efficiently in water in the absence of any organic solvent within 1-2 min.
- Polshettiwar, Vivek,Varma, Rajender S.
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p. 397 - 400
(2008/09/17)
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- Novel application of the palladium-catalyzed N-arylation of hydrazones to a versatile new synthesis of pyrazoles
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A versatile synthesis of pyrazoles from aryl benzophenone hydrazones was demonstrated with a variety of 1,3-bifunctional substrates under acidic conditions. The obtained regioselectivity is consistent with transhydrazonation followed by subsequent cycliza
- Haddad, Nizar,Baron, James
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p. 2171 - 2173
(2007/10/03)
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