14117-22-7Relevant academic research and scientific papers
P(III)-Assisted Electrochemical Access to Ureas via in situ Generation of Isocyanates from Hydroxamic Acids
Meng, Haiwen,Sun, Kunhui,Xu, Zhimin,Tian, Lifang,Wang, Yahui
supporting information, p. 1768 - 1772 (2021/03/26)
An external oxidant-free protocol for the generation of isocyanates from hydroxamic acids assisted by trivalent phosphine under mild electrochemical conditions was reported. The process started with the anodic oxidation of hydroxamic acids, followed by reacting with phosphine to form corresponding alkoxyphosphoniums and subsequent rearrangement with the release of tri-substituted phosphine oxide as the driving force to give isocyanates, which were trapped by N-based nucleophiles to produce various ureas. This method provides a broadly applicable procedure to access isocyanate intermediates under mild electrochemical conditions.
CaI2-Catalyzed direct transformation of: N -Alloc-, N -Troc-, and N -Cbz-protected amines to asymmetrical ureas
Tran, Van Hieu,Kim, Hee-Kwon
, p. 14093 - 14101 (2019/09/18)
A novel and facile CaI2-catalyzed direct synthesis of asymmetrical ureas from N-Alloc-, N-Troc-, and N-Cbz-protected amines is developed. In this study, the efficient reaction of Alloc-, Troc-, and Cbz-carbamates with amines in the presence of catalytic CaI2 successfully generated various asymmetrical ureas. This catalytic synthetic procedure provided the desired ureas via reactions of these protected aromatic and aliphatic amines with various amines in high yields without side products. This suggests that novel direct synthesis of ureas from Alloc-, Troc-, and Cbz-carbamates can be a promising approach for the synthesis of useful ureas.
A facile dynamic crosslinked healable poly(oxime-urethane) elastomer with high elastic recovery and recyclability
Fu, Daihua,Pu, Wuli,Wang, Zhanhua,Lu, Xili,Sun, Shaojie,Yu, Changjiang,Xia, Hesheng
supporting information, p. 18154 - 18164 (2018/10/02)
Endowing thermoset polymer materials with self-healing and recyclable properties by incorporating dynamic bonds into the polymer networks is of vital realistic significance. However, such materials are still limited because of the difficult synthetic process and expensive dynamic monomers or environment-unfriendly catalysts. Herein, catalyst-free and colorless transparent healable and recyclable poly(oxime-urethane) elastomers based on dynamic oxime-carbamate bonds were developed with scaling-up capability using low-cost and commercially available compounds. These materials display remarkable comprehensive properties and relatively low relaxation activation energy (～29.7 kcal mol-1) which results in excellent healable and recyclable performance. The poly(oxime-urethane) with a crosslink density ν of ～0.2 mmol cm-3 possesses a tensile strength of ～13.5 MPa, a breaking strain of ～812%, toughness up to ～40 MJ m-3, an excellent elastic recovery of ～90% and an average optical transmittance of ～86% in the visible range. This material can be completely healed at 110 °C in 0.5 h. In situ structural characterizations revealed that the dynamic properties originate from the reversibility of oxime-carbamate bonds and hydrogen bonds.
Metal-Free Synthesis of Unsymmetrical Ureas and Carbamates from CO2 and Amines via Isocyanate Intermediates
Ren, Yiming,Rousseaux, Sophie A. L.
, p. 913 - 920 (2018/01/28)
A mild and metal-free synthesis of aryl isocyanates from arylamines under an atmosphere of CO2 was developed. The carbamic acid intermediate, derived from the arylamine starting material and CO2 in the presence of DBU, is dehydrated by activated sulfonium reagents to generate the corresponding isocyanate. The latter can be detected by in situ IR and trapped by various amines and alcohols to make unsymmetrical ureas and carbamates, respectively. Dicarbamates can also be prepared in good yields via the mild dehydration of the corresponding dicarbamic acids.
Efficient Direct Halogenation of Unsymmetrical N -Benzyl- and N -Phenylureas with Trihaloisocyanuric Acids
Sanabria, Carlos M.,Costa, Bruno B. S.,Viana, Gil M.,De Aguiar, Lúcia C. S.,De Mattos, Marcio C. S.
supporting information, p. 1359 - 1367 (2017/12/26)
A simple and efficient methodology for the direct halogenation of N -phenylureas was developed using trihaloisocyanuric acids in acetonitrile at room temperature. This protocol proved to be effective for the construction of N -phenylureas with different patterns of substitution. Additionally, less reactive N -benzylureas were halogenated in the presence of a mixture of trifluoroacetic acid and acetonitrile at room temperature.
Method for synthesizing asymmetric disubstituted urea through catalytic oxidation and carbonylation
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Paragraph 0087; 0088, (2017/12/28)
The invention discloses a novel method for directly synthesizing asymmetric disubstituted urea compounds. The method comprises the step of adding a palladium catalyst into a solvent polyethylene glycol or a polyethylene glycol water solution under the action of alkali, an iodine compound and an oxidant so as to catalyze direct cross coupling reaction of primary amine and carbon monoxide, so as to prepare the asymmetric disubstituted urea compounds. The method for preparing the asymmetric disubstituted urea compounds through the coupling reaction has the advantages that the catalyst is wide in source and environment-friendly; a substrate is wide in source, cheap and easy to process; a carbonyl is stable in source and cheap and does not generate waste; a ligand is not required in the reaction, and the reaction activity is good; reaction conditions are mild, and the reaction selectivity is high; the substrate has good functional group consistency and is wide in application range; and a reaction medium is environment-friendly and can be circularly recycled. The separation yield of a target product can reach up to about 97% under optimized reaction conditions.
A high-yielding, expeditious, and multicomponent synthesis of urea and carbamate derivatives by using triphenylphosphine/trichloroisocyanuric acid system
Ghodsinia, Sara S.E.,Akhlaghinia, Batool
, p. 104 - 110 (2016/01/25)
An efficient method for the synthesis of urea and carbamate derivatives from amines and alcohols is described by using triphenylphosphine (PPh3)/trichloroisocyanuric acid system. The protocol allows for the preparation of symmetrical, unsymmetrical di, tri-, and tetra-substituted ureas and carbamates and is tolerant of a wide range of functional groups. To optimize the reaction conditions, experimental variables including temperature, the concentration of amine and alcohol, solvent, and reaction time were studied. Satisfactory yields were obtained at the optimized conditions. The present methodology is experimentally simple, mild, and represents a valuable alternative to the existing methods.
A synthetic N, N '-di-substituted ureas method
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Paragraph 0175-0178, (2016/11/17)
The invention discloses a method for synthesizing N,N'-disubstituent urea. The method comprises the following steps: adding N-substituent urea, a metal iridium, rhodium or ruthenium complex catalyst, an alkali, a compound alcohol and a solvent (or no solvent) to a reaction container; reacting at 90-130 DEG C for a plurality of hours and cooling the reaction mixture to room temperature; carrying out rotary evaporation to remove the solvent, and then separating through a column, so as to obtain a target compound. Compared with the prior art, N,N'-disubstituent urea which is obtained by regional selective alkylation reaction between commercial or easily synthesized N-substituent urea and the alcohol reflects and displays three significant advantages: 1) the alcohol which is nearly non-toxic is utilized as an alkylating reagent; 2) just water is generated as a by-product in the reaction, and harm to environment is not generated; 3) reaction atom economy is high. Therefore, the reaction accords with the requirements of green chemistry, and has a broad development prospect.
Pd/C Catalyzed Carbonylation of Azides in the Presence of Amines
Zhao, Jin,Li, Zongyang,Yan, Shuaihu,Xu, Shiyang,Wang, Ming-An,Fu, Bin,Zhang, Zhenhua
, p. 1736 - 1739 (2016/05/19)
A facile and efficient Pd/C-catalyzed carbonylation of both aliphatic and aromatic azides in the presence of amines is reported. Serving as the widely existed fragments in an array of biological pharmaceuticals, functionalized unsymmetrical ureas were str
