617-07-2Relevant academic research and scientific papers
Amide-assisted rearrangement of hydroxyarylformimidoyl chloride to diarylurea
Jin, Yi,Liu, Xiaoyu,Song, Xizhong,Yu, Wei
supporting information, (2021/11/11)
A novel amide-assisted rearrangement reaction of hydroxybenzimidoyl chloride has been established for the efficient synthesis of 1,3-diphenylurea derivatives. A variety of electronically and sterically different 1,3-diphenylurea derivatives can be obtained in good to excellent yields, and a proposed reaction mechanism is also presented.
Di-tert-butyl peroxide (DTBP)-mediated synthesis of symmetrical N,N′-disubstituted urea/thiourea motifs from isothiocyanates in water
Chen, Ling,Dong, Yibo,Wu, Yangjie,Yang, Jinchen,Zhang, Jinli
supporting information, (2021/12/01)
ABATRACT: A direct approach to N,N′-disubstituted urea/thiourea from the self-condensation reactions of isothiocyanates in water has been developed. This access tolerated a wide range of functional groups on the aromatic ring, providing a practical and environment-friendly process to N,N′-disubstituted urea/thiourea in moderate to excellent yields from safe and easily available starting materials. A plausible mechanism of the desulfurization self-condensation reaction for urea was also proposed and the role of di-tert-butyl peroxide (DTBP) and copper catalyst in the present strategy was demonstrated with the help of ESI mass spectrometry of intermediate studies.
Palladium-Catalyzed Aerobic Oxidative Carbonylation of Amines Enables the Synthesis of Unsymmetrical N,N′-Disubstituted Ureas
Zeng, Honglan,Du, Hongyan,Gong, Xu,Zhang, Jie,Han, Wei
, p. 1223 - 1226 (2021/06/02)
A ligand-free palladium-catalyzed aerobic oxidative carbonylation of amines for the synthesis of ureas, particular unsymmetrically N,N′-disubstituted ureas, which cannot be accessed by any other palladium-catalyzed oxidative carbonylation of amines to date, is presented. An array of symmetrical and unsymmetrical ureas were straightforwardly synthesized by using inexpensive, readily available, stable, and safe amines with good to excellent yields under a pressure of 1 atm. This novel method employs oxygen as the sole oxidant and offers an attractive alternative to transition-metal-based oxidant systems.
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.
2,2′,2″-(2,4,6-Trioxo-1,3,5-triazinane-1,3,5-triyl)triacetic Acid Derivatives. New Aspects of Reactivity
Kavina, M. A.,Sizov, V. V.
, p. 1046 - 1053 (2020/08/28)
Abstract: Reaction of 2,2′,2″-(2,4,6-trioxo-1,3,5-triazinane-1,3,5-triyl)triacetic acid derivatives with nucleophiles in aqueous medium involved opening of the triazinane ring with elimination of carbonyl group, followed by recyclization to 1-carbamoylhydantoins.
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.
Hydrosilane-Assisted Synthesis of Urea Derivatives from CO2and Amines
Zhao, Yulei,Guo, Xuqiang,Si, Zhiyao,Hu, Yanan,Sun, Ying,Liu, Yunlin,Ji, Zhongyin,You, Jinmao
, p. 13347 - 13353 (2020/11/02)
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.
An Improved Synthesis of Urea Derivatives from N -Acylbenzotriazole via Curtius Rearrangement
Agrahari, Anand K.,Singh, Anoop S.,Singh, Sumit K.,Tiwari, Vinod K.,Yadav, Mangal S.
, p. 3443 - 3450 (2019/09/07)
The good leaving tendency of the benzotriazole moiety has been exploited for the synthesis of symmetric, unsymmetric, N -acyl, and cyclic ureas in good yields from N -acylbenzotriazoles by treating the latter with various amines in the presence of TMSN 3 /Et 3 N in a sealed tube. The salient features of the devised protocol includes the high-yield, mild, metal-free, one-pot reaction conditions, and short reaction time. Furthermore, in many cases, no column chromatography is required for the purification.
Organic ligand and solvent free oxidative carbonylation of amine over Pd/TiO2 with unprecedented activity
Liu, Shujuan,Dai, Xingchao,Wang, Hongli,Shi, Feng
supporting information, p. 4040 - 4045 (2019/08/07)
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.
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
