- Potent natural soluble epoxide hydrolase inhibitors from Pentadiplandra brazzeana Baillon: Synthesis, Quantification, and Measurement of Biological Activities In Vitro and In Vivo
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We describe here three urea-based soluble epoxide hydrolase (sEH) inhibitors from the root of the plant Pentadiplandra brazzeana. The concentration of these ureas in the root was quantified by LC-MS/MS, showing that 1, 3-bis (4-methoxybenzyl) urea (MMU) i
- Kitamura, Seiya,Morisseau, Christophe,Inceoglu, Bora,Kamita, Shizuo G.,De Nicola, Gina R.,Nyegue, Maximilienne,Hammock, Bruce D.
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- A palladium-catalyzed oxidative aminocarbonylation reaction of alkynone: O -methyloximes with amines and CO in PEG-400
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A palladium-catalyzed oxidative aminocarbonylation of O-methyloximes and amines under aerobic conditions with PEG-400 as an environmentally benign medium was accomplished. This novel protocol provides the first straightforward synthetic method for the assembly of structurally diverse 4-carboxamide isoxazoles with high atom- and step-economy and exceptional functional group tolerance. Notably, the employment of ionic liquids as an additive, with air as the sole oxidant, without ligands is an attractive feature of the present approach.
- Li, Jianxiao,Yu, Junsheng,Xiong, Wenfang,Tang, Hao,Hu, Miao,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 465 - 470
(2020/02/13)
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- Amine-Responsive Disassembly of AuI–CuI Double Salts for Oxidative Carbonylation
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A sensitive amine-responsive disassembly of self-assembled AuI-CuI double salts was observed and its utilization for the synergistic catalysis was enlightened. Investigation of the disassembly of [Au(NHC)2][CuI2] revealed the contribution of Cu-assisted ligand exchange of N-heterocyclic carbene (NHC) by amine in [Au(NHC)2]+ and the capacity of [CuI2]? on the oxidative step. By integrating the implicative information coded in the responsive behavior and inherent catalytic functions of d10 metal complexes, a catalyst for the oxidative carbonylation of amines was developed. The advantages of this method were clearly reflected on mild reaction conditions and the significantly expanded scope (51 examples); both primary and steric secondary amines can be employed as substrates. The cooperative reactivity from Au and Cu centers, as an indispensable prerequisite for the excellent catalytic performance, was validated in the synthesis of (un)symmetric ureas and carbamates.
- Cao, Yanwei,Yang, Jian-Gong,Deng, Yi,Wang, Shengchun,Liu, Qi,Shen, Chaoren,Lu, Wei,Che, Chi-Ming,Chen, Yong,He, Lin
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supporting information
p. 2080 - 2084
(2019/12/24)
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- Iron-catalyzed urea synthesis: Dehydrogenative coupling of methanol and amines
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Substituted ureas have numerous applications but their synthesis typically requires the use of highly toxic starting materials. Herein we describe the first base-metal catalyst for the selective synthesis of symmetric ureas via the dehydrogenative coupling of methanol with primary amines. Using a pincer supported iron catalyst, a range of ureas was generated with isolated yields of up to 80% (corresponding to a catalytic turnover of up to 160) and with H2 as the sole byproduct. Mechanistic studies indicate a stepwise pathway beginning with methanol dehydrogenation to give formaldehyde, which is trapped by amine to afford a formamide. The formamide is then dehydrogenated to produce a transient isocyanate, which reacts with another equivalent of amine to form a urea. These mechanistic insights enabled the development of an iron-catalyzed method for the synthesis of unsymmetric ureas from amides and amines.
- Lane, Elizabeth M.,Hazari, Nilay,Bernskoetter, Wesley H.
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p. 4003 - 4008
(2018/05/04)
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- Co-N-doped carbon nanotubes supported on diatomite for highly efficient catalysis oxidative carbonylation of amines with CO and air
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Cobalt-nitrogen-doped carbon nanotubes stably supported on diatomite were obtained by employing Co(OAc)2/phenanthroline. The resulting material was found to be excellent catalysts for the carbonylation of a variety of amines with CO other than phosgene. Both high activity and selectivity were achieved in this carbonylation process, and it allows air as a cheap oxidizing agent. Moreover the catalyst could be recycled for several times with relatively higher activity compared to homogeneous catalyst palladium acetate.
- Li, Jiangwei,Tu, Dong-huai,Li, Yani,Wang, Weiqiang,Yu, Qinwei,Yang, Jianming,Lu, Jian
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p. 112 - 116
(2017/10/09)
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- Ruthenium-Catalyzed Urea Synthesis by N-H Activation of Amines
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Activation of the N-H bond of amines by a ruthenium pincer complex operating via amine-amide metal-ligand cooperation is demonstrated. Catalytic formyl C-H activation of N,N-dimethylformamide (DMF) is observed in situ, which resulted in the formation of CO and dimethylamine. The scope of this new mode of bond activation is extended to the synthesis of urea derivatives from amines using DMF as a carbon monoxide (CO) surrogate. This catalytic protocol allows the synthesis of simple and functionalized urea derivatives with liberation of hydrogen, devoid of any stoichiometric activating reagents, and avoids the direct use of fatal CO. The catalytic carbonylation occurred at low temperature to provide the formamide; a formamide intermediate was isolated. The consecutive addition of different amines provided unsymmetrical urea compounds. The reactions are proposed to proceed via N-H activation of amines followed by CO insertion from DMF and with liberation of dihydrogen.
- Krishnakumar, Varadhan,Chatterjee, Basujit,Gunanathan, Chidambaram
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supporting information
p. 7278 - 7284
(2017/06/23)
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- Ruthenium-Catalyzed Urea Synthesis Using Methanol as the C1 Source
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An unprecedented protocol for urea synthesis directly from methanol and amine was accomplished. The reaction is highly atom-economical, producing hydrogen as the sole byproduct. Commercially available ruthenium pincer complexes were used as catalysts. In addition, no additive, such as a base, oxidant, or hydrogen acceptor, was required. Furthermore, unsymmetrical urea derivatives were successfully obtained via a one-pot, two-step reaction.
- Kim, Seung Hyo,Hong, Soon Hyeok
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supporting information
p. 212 - 215
(2016/02/03)
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- Polynuclear Gold [AuI]4, [AuI]8, and Bimetallic [AuI4AgI] Complexes: C?H Functionalization of Carbonyl Compounds and Homogeneous Carbonylation of Amines
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The synthesis of tetranuclear gold complexes, a structurally unprecedented octanuclear complex with a planar [AuI8] core, and pentanuclear [AuI4MI] (M=Cu, Ag) complexes is presented. The linear [AuI4] complex undergoes C?H functionalization of carbonyl compounds under mild reaction conditions. In addition, [AuI4AgI] catalyzes the carbonylation of primary amines to form ureas under homogeneous conditions with efficiencies higher than those achieved by gold nanoparticles.
- Smirnova, Ekaterina S.,Mu?oz Molina, José M.,Johnson, Alice,Bandeira, Nuno A. G.,Bo, Carles,Echavarren, Antonio M.
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supporting information
p. 7487 - 7491
(2016/07/06)
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- Direct extraction of carbonyl from waste polycarbonate with amines under environmentally friendly conditions: Scope of waste polycarbonate as a carbonylating agent in organic synthesis
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An efficient green method for converting waste polycarbonate into urea derivatives by reacting with primary amines has been developed. Simple treatment of polycarbonate plastic with primary amines in a closed vial at 80 °C without using any catalyst and toxic solvents made this process environmentally friendly. Digestion of the waste polycarbonate obtained from CDs and DVDs with amines affords functionalized urea and 4,4′-(propane-2,2-diyl)diphenol (BPA, bisphenol-A). The procedure is optimized to get maximum conversion of polymer to urea and its derivatives as a major product. The purification procedure to isolate the urea derivatives in the presence of bisphenol-A has been tuned to avoid chromatographic procedures. This environmentally friendly method provides (i) an alternative for recycling BPA from polycarbonate, (ii) a method of obtaining useful product like urea derivatives, (iii) scope for new carbonylating agents in organic synthesis, (iv) an amine functionalized polycarbonate surface. This journal is
- Singh, Sukhdeep,Lei, Yong,Schober, Andreas
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p. 3454 - 3460
(2015/02/19)
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- Synthesis and biological evaluation of glycogen synthase kinase 3 (GSK-3) inhibitors: An fast and atom efficient access to 1-aryl-3-benzylureas
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The glycogen synthase kinase 3 (GSK-3) is implicated in multiple cellular processes and has been linked to the pathogenesis of Alzheimer's disease (AD). In the course of our research topic we synthesized a library of potent GSK-3 inhibitors. We utilized the urea scaffold present in the potent and highly selective GSK-3 inhibitor AR-A014418 (AstraZeneca). This moiety suits both (a) a convergent approach utilizing readily accessible building blocks and (b) a divergent approach based on a microwave heating assisted Suzuki coupling. We established a chromatography-free purification method to generate products with sufficient purity for the biological assays. The structure-activity relationship of the library provided the rationale for the synthesis of the benzothiazolylurea 66 (IC50 = 140 nM) and the pyridylurea 62 (IC 50 = 98 nM), which displayed two to threefold enhanced activity versus the reference compound 18 (AR-A014418: IC50 = 330 nM) in our assays.
- Monte, Fabio Lo,Kramer, Thomas,Bol?nder, Alexander,Plotkin, Batya,Eldar-Finkelman, Hagit,Fuertes, Ana,Dominguez, Juan,Schmidt, Boris
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supporting information; experimental part
p. 5610 - 5615
(2011/10/09)
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- NaIO4-oxidized carbonylation of amines to ureas
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Oxidative carbonylation of amines using NaIO4 as the oxidant and NaI as a promoter affords good to excellent yields of ureas from primary amines in the absence of transition metal catalysts. The Royal Society of Chemistry 2009.
- Shelton, Phillip A.,Zhang, Yue,Nguyen, Thi Hoang Ha,McElwee-White, Lisa
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supporting information; experimental part
p. 947 - 949
(2009/07/10)
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- A high yielding, one-pot synthesis of substituted ureas from the corresponding amines using Mitsunobu's reagent
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A Mitsunobu-based protocol has been developed for the synthesis of symmetrically and unsymmetrically substituted ureas from a variety of primary and secondary amines using gaseous carbon dioxide, in good to excellent yields. This protocol is mild and efficient compared to other reported methods.
- Chaturvedi, Devdutt,Mishra, Nisha,Mishra, Virendra
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experimental part
p. 267 - 270
(2009/05/26)
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- Efficient synthesis of phenanthridinone derivatives via a palladium-catalyzed coupling process
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(Chemical Equation Presented) A palladium-mediated domino reaction was developed to conveniently synthesize phenanthridinone derivatives. Phosphine ligand 1 strongly promotes the domino process, which includes aryl-aryl coupling and C-N bond formations concomitant with a deamidation reaction. The versatility and applicability to a broad range of substrates make this reaction useful for the development of bioactive derivatives.
- Furuta, Takumi,Kitamura, Yuki,Hashimoto, Ayano,Fujii, Satoshi,Tanaka, Kiyoshi,Kan, Toshiyuki
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p. 183 - 186
(2007/10/03)
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- Solvent-free synthesis of urea derivatives from primary amines and sulfur under carbon monoxide and oxygen at atmospheric pressure
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A solvent-free carbonylation and oxidation system aimed at green and sustainable chemistry was developed. With these reactions, an environmentally benign synthesis of urea derivatives could be carried out in good to excellent yields from primary amines and sulfur at ambient pressure of carbon monoxide and oxygen. For example, N,N′-dioctylurea was prepared in 99% yield from two equivalents octylamine and one equivalent sulfur in the presence of carbon monoxide (1 atm) at 80°C and oxygen (1 atm) at room temperature, in the complete absence of solvent. Georg Thieme Verlag Stuttgart.
- Mizuno, Takumi,Mihara, Masatoshi,Nakai, Takeo,Iwai, Toshiyuki,Ito, Takatoshi
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p. 3135 - 3140
(2008/04/03)
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- Super fast cobalt carbonyl-mediated synthesis of ureas
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Fast cobalt carbonyl-mediated generation of ureas from primary amines was performed using high-density microwave irradiation. This enhanced method permitted the preparation of symmetrical ureas in good yields and unsymmetrical ureas in moderate yields. Th
- Enquist, Per-Anders,Nilsson, Peter,Edin, Johan,Larhed, Mats
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p. 3335 - 3339
(2007/10/03)
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- Self-indicating amine scavenger resins
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Self-indicating methylisocyanate resin, which functions as both a scavenger and an indicator for amines, was used for in-situ reaction monitoring and purification of a urea based library.
- Cho, Jin Ku,White, Peter D.,Klute, Wolfgang,Dean, Tony W.,Bradley, Mark
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p. 502 - 503
(2007/10/03)
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- W(CO)6-catalyzed oxidative carbonylation of primary amines to n,n'-disubstituted ureas in single or biphasic solvent systems. Optimization and functional group compatibility studies
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Primary amines undergo carbonylation to N,N'-disubstituted ureas using W(CO)6 as the catalyst, I2 as the oxidant, and CO as the carbonyl source. Preparation of various N,N'-disubstituted ureas from aliphatic primary amines, RNH2 (R = n-Pr, n-Bu, i-Pr, sec-Bu, or t-Bu), was achieved in good to excellent yields. Studies of functional group compatibility using a series of substituted benzylamines demonstrated broad tolerance of functionality during the carbonylation reaction. Preparation of various N,N'-disubstituted ureas from substituted benzylamines, R-C6H4CH2NH2 (R = H, p-OCH3, p-CO2H, p-CO2Et, p-CH2OH, p-SCH3, p-vinyl, p-Cl, p-Br, m-I, p-NH2, p-NO2, or p-CN), was achieved in good yields. For many substituted benzylamines, yields of ureas were higher when a two-phase CH2Cl2/H2O solvent system was used.
- McCusker, Jennifer E.,Main, A. Denise,Johnson, Kirsten S.,Grasso, Cara A.,McElwee-White, Lisa
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p. 5216 - 5222
(2007/10/03)
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- NEW PROCEDURES FOR THE SYNTHESIS OF SYMMETRICAL BISBENZYLATED UREAS BASED ON N-BENZYLTRICHLOROACETAMIDES
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Treatment of N-benzylated trichloroacetamides 4, obtained by three different procedures, with potassium carbonate in dimethylsulfoxide affords simmetrical bisbenzylated ureas 5.
- Atanassova, I.A.,Petrov, J.S.,Mollov, N.M.
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p. 147 - 154
(2007/10/02)
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