- Hydrosilane-Assisted Synthesis of Urea Derivatives from CO2and Amines
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A methodology employing CO2, amines, and phenylsilane was discussed to access aryl- or alkyl-substituted urea derivatives. This procedure was characterized by adopting hydrosilane to promote the formation of ureas directly, without the need to prepare silylamines in advance. Control reactions suggested that FeCl3 was a favorable additive for the generation of ureas, and this 1,5,7-triazabicyclo[4.4.0]dec-5-ene-catalyzed reaction might proceed through nucleophilic addition, silicon migration, and the subsequent formal substitution of silylcarbamate.
- Zhao, Yulei,Guo, Xuqiang,Si, Zhiyao,Hu, Yanan,Sun, Ying,Liu, Yunlin,Ji, Zhongyin,You, Jinmao
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p. 13347 - 13353
(2020/11/02)
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- Urea-based derivative and synthesis method thereof
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The invention discloses a urea-based derivative and a synthesis method thereof. The synthesis method comprises: adding an amine-based catalyst into an amine-based compound used as a raw material, introducing carbon dioxide gas into a reaction bottle, sequentially adding a solvent, hydrosilane and a Lewis acid catalyst into the reaction bottle in the atmosphere of carbon dioxide gas, and carrying out a one-pot reaction to catalytically synthesize the urea-based derivative represented by a formula (I). According to the invention, the preparation method has advantages of mild reaction conditions,simple and easily available raw materials, simple and easily available amine-based catalyst, simple and easily available Lewis acid catalysts, good substrate universality, simple and convenient post-treatment, good yield and the like. The invention further discloses applications of the urea-based derivative represented by the formula (I) in the fields of synthesis and medicinal chemistry.
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Paragraph 0063-0069
(2020/02/08)
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- Zinc Powder Catalysed Formylation and Urealation of Amines Using CO2 as a C1 Building Block?
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Transformation of CO2 into valuable organic compounds catalysed by cheap and biocompatible metal catalysts is one of important topics of current organic synthesis and catalysis. Herein, we report the zinc powder catalysed formylation and urealation of amines with CO2 and (EtO)3SiH under solvent free condition. Using 2 molpercent zinc powder as the catalyst, a series of secondary amines, both the aromatic ones and the aliphatic ones, can be formylated into formamides. When primary aromatic amines were used as the substrates, the reactions produce urea derivatives. The electronic and steric effects from the substrates on the formylation and urealation reactions were observed and discussed. The recovery and reusability of zinc powder were investigated, showing the zinc powder can be reused in the formylation reaction without loss of catalytic activity. The analysis on the reactants/products mixture after filtering out the zinc powder showed the zinc concentration in the mixture is low to 1 ppm. The pathways for the formylation and urealation of amines with this catalytic system were also investigated, and related to the different substrates.
- Du, Chongyang,Chen, Yaofeng
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p. 1057 - 1064
(2020/06/30)
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- Concise and Additive-Free Click Reactions between Amines and CF3SO3CF3
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Trifluoromethyl trifluoromethanesulfonate has proved to be an excellent reservoir of difluorophosgene and a promising click ligation for amines in the preparation of urea derivatives, heterocycles, and carbamoyl fluorides under metal- and additive-free conditions. The reactions are rapid, efficient, selective, and versatile, and can be performed in benign solvents, giving products in excellent yields with minimal efforts for purification. The characteristics of the reactions meet the requirements of a click reaction. The use of trifluoromethyl trifluoromethanesulfonate as a click reagent is advantageous over other “CO” sources (e.g., TsOCF3, PhCO2CF3, CsOCF3, AgOCF3, and triphosgene) because this reagent is readily accessible; easy to scale up; and highly reactive, even under metal- and additive-free conditions. It is anticipated that CF3SO3CF3 will be increasingly as important as SO2F2 as a click agent in future drug design and development.
- Song, Hai-Xia,Han, Zhou-Zhou,Zhang, Cheng-Pan
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supporting information
p. 10907 - 10912
(2019/08/02)
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- Organic ligand and solvent free oxidative carbonylation of amine over Pd/TiO2 with unprecedented activity
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A highly active Pd/TiO2 catalyst system was prepared and applied in the oxidative carbonylation of amines to ureas with ultra-low Pd content under organic ligand and solvent free conditions. The catalytic turnover frequencies (TOFs, moles of amines converted per mole of Pd per h) were 126000 and 250000 h-1 for the production of diphenylurea and dibenzylurea, respectively. An expanded substrate scope including the electron-rich and electron-deficient anilines, primary aliphatic amines, secondary amines was also established. This work offers a straightforward, step economic, and green methodology for the efficient synthesis of valuable ureas.
- Liu, Shujuan,Dai, Xingchao,Wang, Hongli,Shi, Feng
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supporting information
p. 4040 - 4045
(2019/08/07)
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- One-pot synthesis of symmetrical 1,3-diarylureas or substituted benzamides directly from benzylic primary alcohols and effective oxidation of secondary alcohols to ketones using phenyliodine diacetate in combination with sodium azide
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Benzylic primary alcohols can be directly converted into symmetrical 1,3-diarylureas or substituted benzamides via an one-pot oxidative reaction using the combined reagent of phenyliodine diacetate and sodium azide. This new reaction constitutes a step-economical way to prepare symmetric 1,3-diarylureas or substituted benzamides depending upon the substituents on the phenyl rings of starting alcohols. The sodium acetate generated in situ from the ligand exchange between phenyliodine diacetate and sodium azide plays the pivotal role in the formation of 1,3-diarylureas. In addition, it is also found that various secondary alcohols can be readily oxidized to their corresponding ketones in excellent yields using the same reagent system of phenyliodine diacetate and sodium azide. Generally, secondary alcohols are preferentially oxidized to the corresponding ketones in the presence of primary ones with the limited amounts of phenyliodine diacetate and sodium azide.
- Li, Xiao-Qiang,Wang, Wei-Kun,Han, Yi-Xin,Zhang, Chi
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experimental part
p. 2588 - 2598
(2010/12/25)
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- Cobalt/rhodium heterobimetallic nanoparticle-catalyzed oxidative carbonylation of amines in the presence of carbon monoxide and molecular oxygen to ureas
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An environmentally friendly oxidative carbonylation of aliphatic and aromatic primary amines to ureas has been successfully achieved in the presence of a catalytic amount of cobalt/rhodium heterobimetallic nanoparticles without any promoters. The catalyst system could be reused with only a slight loss of catalytic activity.
- Park, Ji Hoon,Yoon, Jae Chun,Chung, Young Keun
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supporting information; experimental part
p. 1233 - 1237
(2009/12/07)
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