175278-34-9Relevant academic research and scientific papers
Zinc Powder Catalysed Formylation and Urealation of Amines Using CO2 as a C1 Building Block?
Du, Chongyang,Chen, Yaofeng
, p. 1057 - 1064 (2020/06/30)
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.
Method for preparing symmetric urea compound
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Paragraph 0038-0043; 0092-0097, (2020/03/25)
The invention provides a novel reaction system for synthesizing a symmetric urea compound by taking CO2 as a carbonylation reagent, wherein Lewis base and hydrosilane are used as accelerators and efficiently enable an aromatic/aliphatic primary amine compound to react with normal-pressure CO2 to generate corresponding symmetric urea compounds containing different functional groups under mild conditions (100 DEG C, diglyme). According to the method, normal-pressure CO2 is used as an environmentally-friendly non-toxic carbonylation reagent, and cheap Lewis base and PMHS (industrial silicon waste) are used as accelerators, so that the use of toxic carbonylation reagents, isocyanate, high-pressure CO2, expensive dehydrating agents and precious metals is avoided, purification and separation ofintermediates are not needed, pure products can be obtained only through simple suction filtration and separation after the reaction is finished, and the method is an efficient and novel synthesis method and has high industrial application value.
Synthesis of Urea Derivatives from CO2 and Silylamines
Xu, Maotong,Jupp, Andrew R.,Ong, Maegan S. E.,Burton, Katherine I.,Chitnis, Saurabh S.,Stephan, Douglas W.
supporting information, p. 5707 - 5711 (2019/04/16)
A series of thirty-three N,N′-diaryl, dialkyl, and alkyl-aryl ureas have been prepared in pyridine or toluene by reaction of silylamines with CO2. This protocol is shown to provide facile access to 13C-labeled ureas, as well as chiral and macrocyclic ureas. These reactions proceed through initial generation of the corresponding silylcarbamates, which subsequently react with silylamine under thermal conditions to afford the thermodynamically favored urea and disilyl ether.
A simple and efficient synthesis of diaryl ureas with reduction of the intermediate isocyanate by triethylamine
Zhou, Shuguang,Yao, Ting,Yi, Jicheng,Li, Dashuai,Xiong, Jing
, p. 315 - 319 (2013/07/27)
Thirty symmetrical diaryl urea derivatives were synthesised in moderate to excellent yields from arylamine and triphosgene with triethylamine as a reducing agent for the intermediate, isocyanate. It was significant that part of the products could be collected in almost quantitative yield without column chromatography. The procedure under mild reaction conditions was tolerant of a wide range of functional groups. The structures of the compounds were determined by NMR, MS and X-ray crystallographic analyses.
Conformation and stereodynamics of 2,2′-disubstituted N,N′-diaryl ureas
Clayden, Jonathan,Lemiegre, Loic,Pickworth, Mark,Jones, Lyn
supporting information; experimental part, p. 2908 - 2913 (2009/02/02)
Except in the most hindered of cases, N,N′-diaryl N,N′-dimethyl ureas adopt a conformation with the two aryl rings disposed cis to one another. Variable temperature NMR studies reveal the rate at which the Ar-N bonds rotate as well as the conformational preference of ortho disubstituted ureas in which more than one cis orientation is possible. In general, a conformation in which the aryl rings lie close in space but with their most bulky 2-substituents aligned anti is preferred, but with particularly bulky 2-substituents, conformations in which one of the aryl rings points away from the other may also be populated. The Royal Society of Chemistry.
Indole synthesis by controlled carbolithiation of o-aminostyrenes
Kessler, Albane,Coleman, Claire M.,Charoenying, Patchanee,O'Shea, Donal F.
, p. 7836 - 7846 (2007/10/03)
An effective synthesis of the functionalized indole ring system has been developed from substituted o-aminostyrene starting material. Our methodology involves a novel cascade reaction sequence of alkyllithium addition to the styrene double bond and subsequent trapping of the intermediate organolithium with a suitable electrophile, followed by an in situ ring closure and dehydration to generate the indole ring. This new reaction sequence allows for the introduction of molecular diversity at all positions on the indole scaffold. The procedure was shown to be successful with a range of both C and N substituents on the o-aminostyrenes. The reaction sequence was tolerant to the reactivity range of alkyllithiums such as tert-, sec-, and n-butyllithium. The electrophiles used were DMF, which generated indole products with C-2 unsubstituted, and nitriles, which incorporated the nitrile substituent at C-2. The o-aminostyrene starting materials were generated by a Pd-catalyzed cross-coupling reaction of a vinyl boronic acid equivalent with the readily available substituted o-bromoanilines.
Carbonylation of doubly lithiated N′-aryl-N,N-dimethylureas: A novel approach to isatins via intramolecular trapping of acyllithiums
Smith, Keith,El-Hiti, Gamal A.,Hawes, Anthony C.
, p. 2047 - 2052 (2007/10/03)
Lithiation of N′-(2-bromoaryl)-N,N-dimethylureas with methyllithium and tert-butyllithium under nitrogen in anhydrous THF at 0°C gave doubly lithiated arylurea derivatives, which react with carbon monoxide at 0°C to give isatins in good yields. The scope of the reaction has been demonstrated by application to the synthesis of isatin itself and four substituted isatins beating alkyl, chloro or fluoro groups.
Organic-fluorous phase switches: A fluorous amine scavenger for purification in solution phase parallel synthesis
Linclau, Bruno,Sing, Ashvani K.,Curran, Dennis P.
, p. 2835 - 2842 (2007/10/03)
The synthesis of the fluorous amine scavenger [(C6F13CH2CH2)3SSiCH 2CH2CH2]2NH and its successful application in the automated solution phase parallel synthesis of a urea library are described. Ureas were made by robotic synthesis from organic amines and excess isocyanates. The amine scavenger reacts with excess isocyanate, and the fluorous tag serves to solubilize the resulting adduct in the fluorous phase so it can be removed by fluorous-organic extraction. Organic urea products are isolated in high yields and purities after liquid - liquid extraction. Preliminary biological evaluation shows that several of the ureas have ion channel modulation abilities. In contrast to polymer and ionic quenching methods, the fluorous quench works whether the product is soluble or insoluble in the reaction medium, and ionizable functional groups are tolerated in the products.
