13208-19-0Relevant academic research and scientific papers
Investigation of active sites using solid state 27Al and 31P MAS NMR in ceramic amorphous aluminophosphate materials prepared from different potassium salts of phosphate for the synthesis of diphenyl urea derivatives
Harish,Kathyayini,Baby, Bindhu,Nagaraju
, (2021/04/19)
Ceramic amorphous aluminophosphate (CAmAlP) catalysts were prepared by precipitation method using different phosphate salts of potassium such as KH2PO4, K4P2O7 and K2HPO4 as well as H3PO4. The prepared materials were characterized by PXRD, FT-IR, XPS, SEM, BET Surface area, NH3-TPD, 27Al NMR and 31P NMR analytical methods. The catalytic activity of the materials was checked in the synthesis of diphenyl urea (DPU) from aniline and diethyl carbonate, under refluxing conditions. Further, the general application of the catalysts was tested using various substituted anilines. The recyclability of the catalysts was also studied. Uncertainties in percentage yields were calculated to check the reproducible surface properties. The P-XRD, BET Surface area and NH3-TPD results indicated that the materials were amorphous with mesoporous texture, surface areas and acidities in the range 200–260 m2/g and 0.4–0.7 mmol/g respectively. 27Al NMR studies revealed that Al is present in three different coordination states such as tetrahedral, pentagonal and octahedral. The relative percentages of these Al sites depends on the type of the potassium precursor phosphate salt used. Both tetrahedral and pentagonal Al sites in conjunction with each other represented catalytically active sites. An increase in the pentagonal sites contributed to additional increments to the catalytic activity of CAmAlP. The catalyst prepared from KH2PO4 was found to be the best and demonstrated 96% DPU yield.
Method for preparing symmetric urea compound
-
Paragraph 0038-0043; 0074-0079, (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.
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.
N,N'-disubstituted urea compound and synthesis method thereof
-
Paragraph 0071-0074, (2019/04/10)
The invention discloses an N,N'-disubstituted urea compound and a preparation method thereof. N-alkyl acyloxy amide is taken as a raw material and a dichloro(p-cymene)ruthenium(II) dimer complex is taken as a catalyst for carrying out a reaction in an organic solvent under the presence of silver acetate, and the N,N'-disubstituted urea compound is prepared. Compared with the prior art, the methodhas the following advantages that only an amide derivative is taken as a raw material, reaction conditions are mild, the application range of substrates is wide, operation is simple and convenient, the catalyst is low in price, and selectivity of the product is high.
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.
Effective approach to ureas through organocatalyzed one-pot process
Wang, Mingliang,Han, Jilai,Si, Xiaojia,Hu, Yimin,Zhu, Jidong,Sun, Xun
supporting information, p. 1614 - 1618 (2018/03/28)
An efficient approach to N, N′-unsymmetrically substituted ureas 9 has been developed through the ammonolysis process of N-Boc protected anilines 7 with amines prompted by 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). Moreover, a convenient protocol for the
Sulfated polyborate-catalyzed efficient and expeditious synthesis of (un)symmetrical ureas and benzimidazolones
Rekunge, Deelip S.,Khatri, Chetan K.,Chaturbhuj, Ganesh U.
supporting information, p. 4304 - 4307 (2017/10/12)
The excellent catalytic potential of sulfated polyborate is utilized in the synthesis of (un)symmetrical ureas and benzimidazolones by heating amines or substituted OPDA and urea or N-phenylureas under a solvent-free condition at 120 °C is described. The key advantages of the present protocol are phosgene-free, and other hazardous reagents or organic solvent free, high reaction rates and yields, simple workup procedure, and recyclability of the catalyst.
Ortho-substituent effects on diphenylurea packing motifs
Solomos, Marina A.,Watts, Taylor A.,Swift, Jennifer A.
, p. 5065 - 5072 (2018/03/01)
Hydrogen bonding between urea groups is a widely used motif in crystal engineering and supramolecular chemistry studies. In an effort to discern how the steric and electronic properties of substituents affect the molecular conformation and crystal packing
An efficient one-pot synthesis of: N, N ′-disubstituted ureas and carbamates from N -acylbenzotriazoles
Singh, Anoop S.,Kumar, Dhananjay,Mishra, Nidhi,Tiwari, Vinod K.
, p. 84512 - 84522 (2016/10/12)
A facile and high-yielding one-pot synthesis of carbamates and N,N′-disubstituted symmetrical ureas from N-acylbenzotriazoles has been devised. It is believed that, the intermediate acyl-azide undergo Curtius rearrangement and in different solvents gives different products i.e. carbamates in alcohols and N,N′-disubstituted symmetrical urea in THF.
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.
