- Iodine-catalyzed oxidative annulation: Facile synthesis of pyrazolooxepinopyrazolones: Via methyl azaarene sp3C-H functionalization
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An iodine-catalyzed methyl azaarene sp3 C-H functionalization has been developed for the synthesis of a seven-membered O-heterocyclic architecture containing three different heterocyclic aromatic hydrocarbons. This method can be applied to a wide range of substituted methyl azaarenes and diverse 2,4-dihydro-3H-pyrazol-3-ones, and brings about the efficient preparation of 2,9-dihydrooxepino[2,3-c:6,5-c′]dipyrazol-3(7H)-ones in high yields with the merits of low catalyst loading, good functional group tolerance and metal-free conditions.
- Zhang, Xin-Ke,Miao, Xiao-Yu,Zhou, Yu,Wang, Yu-Mei,Song, Ying-Chun,Liu, Hang,Xiong, Yi-Lu,Li, Ling-Yu,Wu, An-Xin,Zhu, Yan-Ping
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supporting information
p. 1236 - 1242
(2022/02/19)
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- Rhodium-Catalyzed [4+2] Annulation of N-Aryl Pyrazolones with Diazo Compounds To Access Pyrazolone-Fused Cinnolines
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An efficient synthesis of novel dinitrogen-fused heterocycles such as pyrazolo[1,2-a]cinnoline derivatives have been accomplished by the rhodium(III)-catalyzed reaction of N-arylpyrazol-5-ones with α-diazo compounds. This reaction proceeds through a cascade C?H activation/intramolecular cyclization with a broad substrate scope. Furthermore, this protocol is successfully extended to the unusual phosphorus-containing α-diazo compounds and cyclic diazo compounds as the cross-coupling partners to deliver the two new kinds of pyrazolo[1,2-a]cinnolinones. The control experiments were performed to reveal insight into the mechanism of this reaction, involving reversible C?H activation, migratory insertion of the diazo compound, and cascade cyclization as the key steps of the transformation. Moreover, gram-scale synthesis and further transformation of the target product demonstrate the synthetic utility of the present protocol.
- Dhole, Sandip,Huang, Wan-Wen,Huang, Ying-Ti,Lin, Chih-Yu,Sun, Chung-Ming
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supporting information
p. 4984 - 4992
(2021/09/28)
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- Preparation method of eltrombopag intermediate and preparation method of eltrombopag diethanolamine salt
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The invention provides a preparation method of an eltrombopag intermediate and a preparation method of eltrombopag diethanolamine salt, and relates to the technical field of medicinal chemistry. According to the preparation method of the eltrombopag intermediate, p-bromophenol is taken as a raw material, and the problem of poor selectivity of nitration reaction is solved. After iodination, the coupling reaction yield of the intermediate compound as shown in a formula (I) and phenylboronic acid is high. Subsequently reduction reaction is carried out, the debromination reaction is complete, the yield is 90% or more, the refining is simpler, and the synthesis yield of the compound of the formula (I) is higher and the operation is simple. Through the improvement, the yield of the key compound shown as the formula (I) is relatively high, the subsequent treatment operation is simple, the process is easy for amplified production, the yield of the whole synthesis process of the eltrombopag diethanolamine salt is 48.1%, the operation is simple, less three wastes are generated, and the synthesis process is suitable for amplified production.
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Paragraph 0051-0052; 0054
(2021/06/22)
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- Electrochemical synthesis of versatile ammonium oxides under metal catalyst-, exogenous-oxidant-, and exogenous-electrolyte-free conditions
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An electrochemical oxidative cross-coupling reaction between 2.5-substituted-pyrazolin-5-ones and ammonium thiocyanate has been developed, which resulted in a series of unprecedented cross-coupling products under metal catalyst-, exogenous-oxidant-, and exogenous-electrolyte-free conditions. It is worth noting that since the resulting cross-coupling products are nearly insoluble in MeCN, the pure product could be afforded without silica gel column purification. In addition, the prepared ammonium oxides are versatile building blocks for synthesizing functionalized pyrazole derivatives.
- Yuan, Yong,Li, Liang-Sen,Zhang, Lin,Wang, Feng,Jiang, Lin,Zuo, Lin,Wang, Qi,Hu, Jian-Guo,Lei, Aiwen
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supporting information
p. 2768 - 2771
(2021/03/23)
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- Metal-Free Direct C–H Thiolation and Thiocyanation of Pyrazolones
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Metal-free approach for direct C–H thiolation and thiocyanation of N-substituted pyrazolones with disulfides and thiocyanate salts, respectively, are developed. These reactions allow the C–S bond coupling to proceed effectively under mild conditions, providing useful and convenient methods for preparation of a series of 4-thio-substituted pyrazolone analogues, which have potential applications in organic, medicinal and material chemistry. Preliminary mechanistic investigation suggested that radical processes are likely to involve in these transformations.
- Kittikool, Tanakorn,Yotphan, Sirilata
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supporting information
(2020/02/13)
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- Synthesis of pyrazolones and pyrazoles via Pd-catalyzed aerobic oxidative dehydrogenation
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A palladium-catalyzed oxidative dehydrogenation reaction in the presence of AMS and base to synthesize pyrazolones and pyrazoles was identified. This method can be utilized to a wide range of substrates, operates under mild react conditions and can give high yields. We believe it could be used as an alternative protocol for the classical dehydrogenation reactions.
- Zhu, Ye-Fu,Wei, Bo-Le,Wei, Jiao-Jiao,Wang, Wen-Qiong,Song, Wei-Bin,Xuan, Li-Jiang
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supporting information
p. 1202 - 1205
(2019/03/29)
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- DABCO-catalyzed silver-promoted direct thiolation of pyrazolones with diaryl disulfides
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A highly efficient protocol for a direct thiolation of N-substituted pyrazolones with diaryl disulfides is described. Using a combination of DABCO and silver(i) acetate, the C-S bond formation proceeds smoothly at room temperature under mild and easy to handle conditions. This synthetic strategy offers a convenient and direct modification of antipyrine and other pyrazolone substrates, giving a series of aryl sulfide-substituted pyrazolone products in moderate to excellent yields.
- Thupyai, Akkharaphong,Pimpasri, Chaleena,Yotphan, Sirilata
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supporting information
p. 424 - 432
(2018/02/06)
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- Copper/Persulfate-Promoted Oxidative Decarboxylative C?H Acylation of Pyrazolones with α-Oxocarboxylic Acids: Direct Access to 4-Acylpyrazolones under Mild Conditions
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A facile and efficient oxidative C?H acylation of N-substituted pyrazolones using α-oxocarboxylic acids as an acyl group source was developed. A combination of Cu(OAc)2 and K2S2O8 enables the reaction to proceed smoothly under air and provides a wide array of 4-acylpyrazolone products in moderate to excellent yields. The mechanism of this transformation is believed to proceed via a copper-induced decarboxylation to form the acyl-copper species. This method provides a convenient and useful route for a direct installation of an acyl moiety into bioactive pyrazolone derivatives, which can be further utilized in many applications. (Figure presented.).
- Kittikool, Tanakorn,Thupyai, Akkharaphong,Phomphrai, Khamphee,Yotphan, Sirilata
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supporting information
p. 3345 - 3355
(2018/09/10)
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- Double-ring substituted pyrazolone azo derivatives, their preparation and use (by machine translation)
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The invention belongs to the field of pharmaceutical chemicals, relates to a twin-ring substituted pyrazolone azo derivatives, preparation method thereof, its pharmaceutical composition and use thereof. In particular, the present invention is shown in formula I compound or its pharmaceutically acceptable salt or solvate. The invention relates also to the preparation method of the compound I, which comprises a pharmaceutical composition and their pharmaceutical use. The invention of the formula I compounds are effective TPO agonist, is good medicine for treating thrombocytopenia. Type I. (by machine translation)
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Paragraph 0095; 0105; 0106; 0108
(2017/01/02)
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- Semicarbazone derivatives and their use as thrombopoietin mimetics
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Compounds of formula (I), particularly a compound of formula (Ia), are non-peptide TPO mimetics, useful in the treatment of thrombocytopenia.
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Page column 10
(2008/06/13)
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- Thrombopoietin mimetics
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Non-peptide TPO mimetics are disclosed, as well as a method of treating thrombocytopenia, in a mammal, including a human, in need thereof, which comprises administering to such mammal an effective amount of a selected hydroxy-1-azo-naphthalene derivative.
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Page column 21
(2008/06/13)
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- Hydrazinonaphthalene and azonaphthalene thrombopoietin mimics are nonpeptidyl promoters of megakaryocytopoiesis
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High-throughput screening for the induction of a luciferase reporter gene in a thrombopoietin (TPO)-responsive cell line resulted in the identification of 4-diazo-3-hydroxy-1-naphthalene-sulfonic acids as TPO mimics. Modification of the core structure and adjustment of unwanted functionality resulted in the development of (5-oxo-1,5-dihydropyrazol-4-ylidene)hydrazines which exhibited efficacies equivalent to those of TPO in several cell-based assays designed to measure thrombopoietic activity. Furthermore, these compounds elicited biochemical responses in TPO-receptor-expressing cells similar to those in TPO itself, including kinase activation and protein phosphorylation. Potencies for the best compounds were high for such low molecular weight compounds (MW 50 values in the region of 1-20 nM.
- Duffy,Darcy,Delorme,Dillon,Eppley,Erickson-Miller,Giampa,Hopson,Huang,Keenan,Lamb,Leong,Liu,Miller,Price,Rosen,Shah,Shaw,Smith,Stark,Tian,Tyree,Wiggall,Zhang,Luengo
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p. 3730 - 3745
(2007/10/03)
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