- Highly efficient ionic liquid-mediated palladium complex catalyst system for the oxidative carbonylation of amines
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A highly efficient catalyst system, palladium-ionic liquid, was developed for the carbonylation of amines to give carbamate or urea. The desired products could be precipitated by adding water into the resulting mixture and the catalyst system could be reused with slight loss of catalytic activity. BMImBF4 ionic liquid + Pd(phen)Cl2 was an effective catalytic system for the oxidative carbonylation of aniline to give corresponding carbamate and for the cyclohexyl amine to give urea. The diversity of the ionic liquids could form an optimal homogeneous catalyst system with a specific organometallic toward specific reactions. There existed strong interactions between the ionic liquid and the Pd complex, which might enhance and stabilize the Pd complex catalyst.
- Shi, Feng,Peng, Jiajian,Deng, Youquan
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- Synthesis, characterization and hirshfeld surface analysis of a 2-thiophene acetic acid derivative
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N,N′-dicyclohexylcarbamoyl-2-(thiophen-2-yl)acetamide (C19H28N2 O2S), was prepared using 1,3-dicyclohexylurea. The compound has been characterized by IR, and single-crystal X-ray diffraction followed by a detailed Hirshfeld surface analysis. The compound crystallizes in the monoclinic space group P21/c, with cell parameters a = 9.0969(3) ?, b = 18.3067(5) ?, c = 11.6499(3) ?, β = 103.876(2)°, V = 1883.49(10) ?3, Z = 4. The crystal structure of the compound is stabilized by the intermolecular interactions of types N-H?O, C-H?O and intramolecular interactions of the type C-H?O.
- Rani, N. Latha,Chakravarthy,Mohana,Lokanath,Sridhar
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- Preparation of 5-diaminomethylenebarbiturates by barbituric acid addition to carbodiimides
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Through NMR spectroscopic monitoring of barbituric acid addition to carbodiimide, a general synthetic procedure for the preparation of 5-diaminomethylenebarbiturates (DABA) was developed. This procedure is very simple and applicable to the preparation of large quantities of DABA derivatives. Through an X-ray structural study of one of the DABA derivatives, it was established that these compounds have an ylide-type structure with strong charge separation within the molecule.
- Jursic, Branko S.,Douelle, Fred,Stevens, Edwin D.
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- Cytotoxicity of doxorubicin conjugated with C60 fullerene. Structural and in vitro studies
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Conjugating an anticancer drug of high biological efficacy but large cytotoxicity with a “transporting” molecule of low toxicity constitutes a valuable approach to design safe drug delivery system. In the present study, doxorubicin (DOX) a drug of large cardiotoxicity was chemically conjugated to a C60-fullerene. The synthesized molecule, a fullerene-doxorubicin conjugate (Ful-DOX), was characterized using the 1H NMR and MALDI TOF mass spectrometry. The absorption and fluorescence spectra and dynamic light scattering of the conjugate were recorded in an aqueous solution, while the impact on viability of several cancer cell lines of the free DOX and the conjugate was compared using the SRB and WST-1 assays. A low antiproliferative activity of the conjugate as compared to the free DOX is a consequence of the presence of fullerene moiety in the former, which is also responsible for the conjugate aggregation in an aqueous solution. Unlike free DOX, these aggregates cannot pass through the nuclear membrane (as demonstrated by the confocal microscopy measurements), which makes them marginally cytotoxic.
- Butowska, Kamila,Kozak, Witold,Zdrowowicz, Magdalena,Makurat, Samanta,Rych?owski, Micha?,Ha?, Aleksandra,Herman-Antosiewicz, Anna,Piosik, Jacek,Rak, Janusz
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- Molecular interactions of β-cyclodextrins with monolayers containing adamantane and anthraquinone guest groups
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Complexing abilities of β-cyclodextrin (β-CD) towards anthraquinone derivatives in solution and immobilised on gold surfaces were studied by voltammetry. The association constant of β-CD with 1-aminoanthraquinone in solution was found to be 1.03±0.05×103 M-1 hence, smaller than that with anthraquinone. Capping the surface-immobilised N-(1-anthraquinone) lipoamide with β-CD led to decrease in the heterogeneous electron transfer rate constant due to the change in the immediate environment around the electroactive group. To detect the interactions of β-CD with a non-electroactive guest, N-(1-adamantane) lipoamide (AD-Lip), the CD was modified by the attachment of an anthraquinone group as the electroactive marker. The appearance of the voltammetric peak corresponding to the reduction of the anthraquinone side-group indicated the binding of β-CD to the AD-Lip self-assembled in a monolayer on the gold electrode.
- Swiech, Olga,Chmurski, Kazimierz,Bilewicz, Renata
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- N-(3-Triethoxysilylpropyl)-4-(isothiocyanatomethyl)-cyclohexane-1-carboxamide (TPICC): A heterobifunctional reagent for immobilization of biomolecules on glass surface
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An efficient heterobifunctional reagent, N-(3-triethoxysilylpropyl)-4-(isothiocyanatomethyl)cyclohexane-1-carboxamide (TPICC) has been developed by a simple 'two step reaction' for the preparation of bioconjugates and immobilization of biomolecules such as oligonucleotides, peptides and proteins on the glass surface. The isothiocyanate functionality at one end of the reagent, TPICC was found specific for the ligands having either aminoalkyl (RNH2) or mercaptoalkyl (R-SH) functionality. The synthesis of bioconjugates with the reagent was achieved through its isothiocyanate functionality at one end via the formation of stable thiourea linkage with aminoalkyl and dithiocarbamate linkage with mercaptoalkyl derivatives. The triethoxysilyl functionality of the reagent has been utilized for specific coupling with the virgin glass surface by a very simple methodology.
- Misra, Arvind,Shahid, Mohammad,Dwivedi, Pratibha
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- Total Synthesis of (+)-3-Demethoxyerythratidinone and (+)-Erysotramidine via the Oxidative Amidation of a Phenol
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Oxidative amidation chemistry provides a unified route to aromatic Erythrina alkaloids through a sequence that illustrates new principles and improved conditions to effect a crucial eliminative Curtius-Schmidt rearrangement.
- Paladino, Marco,Zaifman, Joshua,Ciufolini, Marco A.
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- A chirally stable, atropoisomeric, Cα-tetrasubstituted α-amino acid: Incorporation into model peptides and conformational preference
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A variety of model peptides, including four complete humologous series, to the pentamer level, characterized by the recently proposed binaphthyl-based, axially chiral. Cα-tetrasubstituted, cyclic α-amino acid Bin, in combination with Ala. Gly, or Aib residues, was synthesized by solution methods and fully characterized. The solution conformational propensity of these peptides was determined by FT-IR absorption and 1H-NMR techniques. Moreover, the molecular structures of the free amino acid (S)-enantiomer and an Nα-acylated dipeptide alkylamide with the heterochiral sequence -(R)-Bin-Phe- were assessed in the crystal state by X-ray diffraction. Taken together, the results point to the conclusion that β-bends and 310 helices are preferentially adopted by Bin-containing peprides, although the tully extended conformation would also be adopted in solution by the short oligomers to some extent. We also confirmed the tendency of (R)-Bin to fold a peptide chain into right-handed bend and helical structures. The absolute configuration of the Bin residue(s) was correlated with the typically intense exciton-split Cotton effect of the 1Bb binaphthyl transition near 225 nm.
- Formaggio, Fernando,Peggion, Cristina,Crisma, Marco,Toniolo, Claudio,Tchertanov, Luba,Guilhem, Jean,Mazaleyrat, Jean-Paul,Goubard, Yolaine,Gaucher, Anne,Wakselman, Michel
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- Biodegradable thermo-sensitive nanoparticles from poly(L-lactic acid)/poly(ethylene glycol) alternating multi-block copolymer for potential anti-cancer drug carrier
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In order to produce biodegradable thermo-sensitive nanoparticles, alternating multi-block copolymers (MBC) were synthesized by coupling dicarboxylated poly(ethylene glycol) (PEG; Mw 2000) with poly(l-lactic acid) (PLLA)/PEG/PLLA triblock copolymers. Three different multi-block copolymers were synthesized by varying PLLA molecular weight (800 (MBC1), 1600 (MBC2), and 2800 (MBC3)). The MBC formed self-assembled nanoparticles with a unimodal size distribution during a dialysis process. The nanoparticles (NP) had a spherical shape with a size range of 90-330 nm in diameter and critical aggregation concentrations in a range of 5.6-12.6 μg/mL, depending on PLLA length in MBC. The thermo-sensitivity of MBC NP was monitored by the changes in particle size and interior structure as a function of temperature. The particle size slightly decreased as increasing temperature from 37 to 42°C. The interior structure of the NP responded to temperature by altering microviscosity. The microviscosity, measured by the anisotropy (r value) of a fluorescence probe, of MBC1 NP significantly changed with increasing temperature (r = 0.187 at 25°C and 0.216 at 42°C), while MBC2 and MBC3 showed negligible changes in the microviscosity. This indicates that the temperature-dependent interior structure of the NP relied on the portion of PLLA in MBC. The thermo-sensitivity affected to the drug release behavior and cell cytotoxicity. At 42°C, doxorubicin (DOX) loaded MBC1 NP showed enhanced cytotoxicity (～20 times) against Lewis Lung Carcinoma (LLC) cells when compared to that at 37°C.
- Na, Kun,Lee, Kwang Hee,Lee, Don Haeng,Bae, You Han
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- One-pot synthesis of 4-arylidene imidazolin-5-ones by reaction of amino acid esters with isocyanates and α-bromoketones
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A simple and new multicomponent reaction for the one-pot synthesis of substituted 4-arylidene imidazolin-5-ones from l-amino acid methyl esters, iso-, isothio- or isoselenocyanates, and α-bromoketones is demonstrated. Isolation of thiohydantoin and 5-benzylidene 2-thioxoimidazolidin-4-one intermediates revealed a possible reaction mechanism. The strategy was further extended to the synthesis of 2-iminothiazolines and 2-thioxoimidazolin-4-ones.
- Haung, Jia-Yun,Barve, Indrajeet J.,Sun, Chung-Ming
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- Solvent Dependence of Carboxylic Acid Condensations with Dicyclohexylcarbodiimide
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The kinetics of a model dicyclohexylcarbodiimide (DCC)-carboxylic acid condensation have been studied in six organic solvents at low concentrations of DCC and acid.The first bimolecular rate constant for acid addition to DCC (k1), to give an O-acylisourea, and the second bimolecular rate constant (k3) for acid addition to this intermediate, to give an anhydride, are both dependent on the interaction between acid molecules and solvent.These rate constants correlate extremely well with measures of the solvent's hydrogen-bond accepting ability.The rate constant forintramolecular rearrangement from the O-acylisourea to the N-acylurea (k2) is, by contrast, independent of the solvent.Formation of dimers of the acid is not important at these low concentrations, but it appears the reaction favors formation of anhydride whenever retardation of the k1 and k3 rate constants is minimized.This occurs in solvents in which the acid is least soluble.There is, therefore, a delicate interplay between the conditions that favor the pathway producing anhydride: on the one hand high concentrations are favorable while on the other solvents that offer limited solubility are desirable.For synthetic purposes, where anhydride is the more useful product, a careful optimization of solubility and fast k1 and k3 rate constants are required.
- Balcom, Bruce J.,Petersen, Nils O.
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- Improvement of warfarin biopharmaceutics by conjugation with poly(ethylene glycol)
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One of the most used and useful polymers, poly(ethylene glycol) (PEG) was used as a carrier for warfarin. The drug-polymer conjugate was freely water soluble at room temperature. The hydrolytic stability of the PEG-warfarin was investigated at physiological pH and confirmed the stability of the conjugate. In vivo release studies demonstrated a good release of parent drug, without the initial high plasma level of warfarin.
- Zacchigna, Marina,Di Luca, Gabriella,Cateni, Francesca,Maurich, Venerando
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- Oxovanadium(v)-catalyzed amination of carbon dioxide under ambient pressure for the synthesis of ureas
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Carbon dioxide is regarded as a reliable C1 building block in organic synthesis because of the nontoxic, abundant, and economical characteristics of carbon dioxide. In this manuscript, a commercially available oxovanadium(v) compound was demonstrated to serve as an efficient catalyst for the catalytic amination of carbon dioxide under ambient pressure in the synthesis of ureas. The catalytic transformation of chiral amines into the corresponding chiral ureas without loss of chirality was also performed. Furthermore, a gram-scale catalytic urea synthesis under ambient pressure was successfully achieved to validate the scalability of this catalytic activation of carbon dioxide. This journal is
- Moriuchi, Toshiyuki,Sakuramoto, Takashi,Matsutani, Takanari,Kawai, Ryota,Donaka, Yosuke,Tobisu, Mamoru,Hirao, Toshikazu
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p. 27121 - 27125
(2021/08/24)
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- Hydrosilane-Assisted Synthesis of Urea Derivatives from CO2and Amines
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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.
- Zhao, Yulei,Guo, Xuqiang,Si, Zhiyao,Hu, Yanan,Sun, Ying,Liu, Yunlin,Ji, Zhongyin,You, Jinmao
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p. 13347 - 13353
(2020/11/02)
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- Zinc Powder Catalysed Formylation and Urealation of Amines Using CO2 as a C1 Building Block?
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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.
- Du, Chongyang,Chen, Yaofeng
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p. 1057 - 1064
(2020/06/30)
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- METHOD OF PREPARING UREA USING AMINE COMPOUND AND CARBON DIOXIDE
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Disclosed is a production method of urea using an amine compound and carbon dioxide. The production method of urea includes a step of producing urea by using the amine compound and a 2-pyrrolidone derivative as a solvent and reacting with the carbon dioxide, thereby producing high yield cyclic urea under mild reaction conditions and no catalyst conditions.
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Paragraph 0073-0075; 0134-0138; 0164-0165; 0168; 0196
(2020/11/14)
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- Method for preparing symmetric urea compound
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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.
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Paragraph 0038-0043; 0145-0150
(2020/03/25)
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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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- Copper(II)-Photocatalyzed N-H Alkylation with Alkanes
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We report a practical method for the alkylation of N-H bonds with alkanes using a photoinduced copper(II) peroxide catalytic system. Upon light irradiation, the peroxide serves as a hydrogen atom transfer reagent to activate stable C(sp3)-H bonds for the reaction with a broad range of nitrogen nucleophiles. The method enables the chemoselective alkylation of amides and is utilized for the late-stage functionalization of N-H bond containing pharmaceuticals with good to excellent yields. The mechanism of the reaction was preliminarily investigated by radical trapping experiments and spectroscopic methods.
- Donabauer, Karsten,K?nig, Burkhard,Narobe, Rok,Yakubov, Shahboz,Zheng, Yi-Wen
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p. 8582 - 8589
(2020/09/23)
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- Carbonylative C-C bond activation of aminocyclopropanes using a temporary directing group strategy
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Temporary directing groups (TDGs) underpin a range of C-C bond activation methodologies; however, the use of TDGs for the regiocontrolled activation of cyclopropane C-C bonds is underdeveloped. In this report, we show how an unusual ring contraction process can be harnessed for TDG-based carbonylative C-C bond activations of cyclopropanes. The method involves the transient installation of an isocyanate-derived TDG, rather than relying on carbonyl condensation events as used in previous TDG-enabled C-C bond activations.
- Wang, Gang-Wei,Sokolova, Olga O.,Young, Tom. A.,Christodoulou, Ektor M. S.,Butts, Craig P.,Bower, John F.
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p. 19006 - 19011
(2020/11/13)
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- CARBONATE DERIVATIVE PRODUCTION METHOD
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The objective of the present invention is to provide a method for producing a carbonate derivative in a safe and efficient manner. The method for producing a carbonate derivative according to the present invention is characterized in comprising irradiating light on a composition containing a C1-4 halogenated hydrocarbon having one or more kinds of halogen atoms selected from the group consisting of a chlorine atom, a bromine atom and an iodine atom, a nucleophilic functional group-containing compound and the specific base in the presence of oxygen.
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Paragraph 0153-0156; 0167; 0170-0171
(2020/04/09)
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- Graphene Oxide: A Metal-Free Carbocatalyst for the Synthesis of Diverse Amides under Solvent-Free Conditions
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An environmentally friendly, inexpensive, carbocatalyst, graphene oxide (GO) promoted efficient, metal-free transamidation of various carboxamides with aliphatic, cyclic, and aromatic amines is demonstrated. The protocol is equally applicable to phthalimide, urea, and thioamide determining its adaptability. The oxygenated functionalities such as carbonyl (?C=O), epoxy (?O?), carboxyl (?COOH) and hydroxyl (?OH), present on graphene oxide surface impart acidic properties to the catalyst. The graphene oxide being heterogeneous in nature, work efficiently under solvent-free reaction conditions providing desired products in good to excellent yields. The one-pot synthesis of 2,3-Dihydro-5H-benzo[b]-1,4-thiazepin-4-one moiety by GO catalyzed Aza Michael addition followed by intramolecular transamidation is also described. A plausible reaction mechanistic pathway involving H-bonding is discussed. The graphene oxide can be recycled and reused up to five cycles without much loss in catalytic activity. (Figure presented.).
- Patel, Khushbu P.,Gayakwad, Eknath M.,Patil, Vilas V.,Shankarling, Ganapati S.
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supporting information
p. 2107 - 2116
(2019/03/26)
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- Efficient Non-Catalytic Carboxylation of Diamines to Cyclic Ureas Using 2-Pyrrolidone as a Solvent and a Promoter
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Carboxylation reactions of diamines were found to proceed rapidly and non-catalytically, producing corresponding cyclic ureas in excellent yields and selectivities when 2-pyrrolidone (2-PY) was used as a solvent. A similar promoting effect with 2-PY was also observed for the carboxylation of monoamines by carbon dioxide (CO2). Most notably, the carboxylation reactions of mono- and diamines conducted in 2-PY afforded 2–4 times higher yields of corresponding dialkyl ureas and cyclic ureas compared with those in N-methyl-2-pyrrolidone (NMP). Such a dramatic promoting effect using 2-PY is believed to be associated with the multiple hydrogen bonding interactions between 2-PY and the CO2-containing species of amines. Due to such favorable interactions, carboxylation reactions seem to be more facilitated in 2-PY than in NMP. (Figure presented.).
- Hwang, Junhyeok,Han, Donggu,Oh, Jin Joo,Cheong, Minserk,Koo, Hyun-Joo,Lee, Je Seung,Kim, Hoon Sik
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p. 297 - 306
(2018/11/27)
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- Organic ligand and solvent free oxidative carbonylation of amine over Pd/TiO2 with unprecedented activity
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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.
- Liu, Shujuan,Dai, Xingchao,Wang, Hongli,Shi, Feng
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supporting information
p. 4040 - 4045
(2019/08/07)
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- Simple one pot synthesis of ketone from carboxylic acid using DCC as an activator
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Simple one pot procedure for the conversion of carboxylic acid to ketone is described. Various carboxylic acids were converted to the corresponding ketones in excellent manner in presence of N,N′-dicyclohexylcarbodiimide (DCC) and organometallic reagents. Aromatic, heteroaromatic and aliphatic acids were converted to the corresponding ketones smoothly under the optimum conditions using organolithium reagents. In this process, desired products have been isolated from the crude reaction mixtures in moderate yields during the purification process.
- Mekonnen, Habtamu Gelaw,Jana, Samaresh
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supporting information
p. 1382 - 1384
(2019/04/30)
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- Diverse Oxidative C(sp2)-N Bond Cleavages of Aromatic Fused Imidazoles for Synthesis of α-Ketoamides and N-(pyridin-2-yl)arylamides
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An efficient and chemoselective C(sp2)-N bond cleavage of aromatic imidazo[1,2-a]pyridine molecules is developed. A broad scope of amide compounds such as α-ketoamides and N-(pyridin-2-yl)arylamides are afforded as the final products in up to quantitative yields. Diverse C-N bond cleavages are controlled by the oxidative species used in this transformation, with various amide products afforded in a chemoselective fashion. A preliminary study indicated that some α-ketoamides exhibit anti-Tobacco Mosaic Virus activity for potential use in plant protection.
- Xu, Fangzhou,Wang, Yanyan,Xun, Xiwei,Huang, Yun,Jin, Zhichao,Song, Baoan,Wu, Jian
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p. 8411 - 8422
(2019/05/17)
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- Concise and Additive-Free Click Reactions between Amines and CF3SO3CF3
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Trifluoromethyl trifluoromethanesulfonate has proved to be an excellent reservoir of difluorophosgene and a promising click ligation for amines in the preparation of urea derivatives, heterocycles, and carbamoyl fluorides under metal- and additive-free conditions. The reactions are rapid, efficient, selective, and versatile, and can be performed in benign solvents, giving products in excellent yields with minimal efforts for purification. The characteristics of the reactions meet the requirements of a click reaction. The use of trifluoromethyl trifluoromethanesulfonate as a click reagent is advantageous over other “CO” sources (e.g., TsOCF3, PhCO2CF3, CsOCF3, AgOCF3, and triphosgene) because this reagent is readily accessible; easy to scale up; and highly reactive, even under metal- and additive-free conditions. It is anticipated that CF3SO3CF3 will be increasingly as important as SO2F2 as a click agent in future drug design and development.
- Song, Hai-Xia,Han, Zhou-Zhou,Zhang, Cheng-Pan
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supporting information
p. 10907 - 10912
(2019/08/02)
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- Formamides as Isocyanate Surrogates: A Mechanistically Driven Approach to the Development of Atom-Efficient, Selective Catalytic Syntheses of Ureas, Carbamates, and Heterocycles
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Despite the hazardous nature of isocyanates, they remain key building blocks in bulk and fine chemical synthesis. By surrogating them with less potent and readily available formamide precursors, we herein demonstrate an alternative, mechanistic approach to selectively access a broad range of ureas, carbamates, and heterocycles via ruthenium-based pincer complex catalyzed acceptorless dehydrogenative coupling reactions. The design of these highly atom-efficient procedures was driven by the identification and characterization of the relevant organometallic complexes, uniquely exhibiting the trapping of an isocyanate intermediate. Density functional theory (DFT) calculations further contributed to shed light on the remarkably orchestrated chain of catalytic events, involving metal-ligand cooperation.
- Bruffaerts, Jeffrey,Von Wolff, Niklas,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 16486 - 16493
(2019/10/14)
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- Fluorination as tool to improve bioanalytical sensitivity and COX-2-selective antitumor activity of cobalt alkyne complexes
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The cobalt alkyne complex [(prop-2-ynyl)-2-acetoxybenzoate]dicobalthexacarbonyl (Co-ASS) is an auspicious lead, which exhibits its anticancer activity mainly by inhibition of both cyclooxygenases (COX-1 and COX-2). Since COX-2 participates in carcinogenesis, a selective inhibition of that isoenzyme is aimed. To study if fluorination increases the COX-2/COX-1 inhibition ratio of the lead, substitution was respectively performed in the positions 3, 4, 5, and 6 of the aromatic moiety. The complexes 3/4/5F-Co-ASS and to a much lower extent also 6F-Co-ASS showed cytotoxic, antimetabolic, and apoptotic effects in COX-1/2-positive HT-29 and MDA-MB-231 cells and remarkably less activity in the COX-1/2-negative MCF-7 cell line. The metabolic activity in MCF-7 cells was even unaffected up to a concentration of 40 μM. With exception of 6F-Co-ASS, the complexes strongly reduced the PGE2 synthesis in HT-29 cells and all complexes inhibited COX-2 more effectively than COX-1 in an assay at isolated enzymes. These findings point to an interference in the COX cascade as part of the mode of antitumor action. The limited cellular effects of 6F-Co-ASS are related to its poor uptake as determined by HR CS AAS/MAS. Moreover, the cellular uptake studies confirm fluorination as beneficial tool for bioanalytical labeling. The higher quantification of fluorine by HR CS MAS makes this method about 5-fold more sensitive than HR CS AAS measuring cobalt. As a further positive result, 3/4/5/6-Co-ASS demonstrated high selectivity to tumor cells due to lack of antimetabolic activity against the non-tumorigenic bone marrow stromal cell line HS-5.
- Baecker, Daniel,Obermoser, Victoria,Kirchner, Elisabeth Anna,Hupfauf, Andrea,Kircher, Brigitte,Gust, Ronald
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p. 15856 - 15868
(2019/11/11)
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- Cyclodimerization of isocyanates promoted by one large vertex metallaborane
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The 10-vertex Manganese-decaborane [nido-6-Mn(CO)3B9H13][NMe4] was found to act as an efficient catalyst for isocyanate cyclodimerization under photo-irradiation conditions. The reaction yields were comparable with other metal catalyst reported in literature. One of the products was characterized by X-ray crystallographic study and reaction mechanism was also proposed. The results are very encouraging as they represent first examples of a large metallaborane compound to catalyze the cyclodimerization of isocyanates.
- Ma, Pei,Spencer, James T.
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p. 148 - 152
(2018/06/26)
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- Method for synthesizing benzothiazolone-based and 1,3-disubstituted urea-based derivatives through activation of CO2
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The present invention relates to a method for synthesizing benzothiazolone-based and 1,3-disubstituted urea-based derivatives through activation of CO2. According to the present invention, an inexpensive and easily-available sulfur-containing metal salt compound is first used as an activation catalyst for CO2, and a reaction raw material and CO2 are converted into a corresponding target compound at a low reaction temperature under a low CO2 pressure; and the method has high atomic economy, can reduce the generation of by-products, meets the standards of environmental friendliness and environmentally friendly chemistry, and is the effective way capable of completely utilizing CO2 as the renewable resource, developing new energy and achieving the beneficial cycle of carbon in nature.
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Paragraph 0062; 0063; 0064; 0069
(2018/09/12)
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- Urea derivatives for the protection of stem cells
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Suggested are novel urea compounds of formula (I) which are useful in cosmetic and pharmaceutical preparations, in particular in preparations for skin and hair care.
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Paragraph 0129; 0130; 0131; 0132
(2018/07/29)
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- Organic ligand-free carbonylation reactions with unsupported bulk Pd as catalyst
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Herein, surprising results for bulk Pd-catalyzed carbonylation reactions are presented. Three types of carbonylation reactions can be realized efficiently under organic ligand-free conditions, namely, hydroaminocarbonylation of olefins, aminocarbonylation of aryl iodides and oxidative carbonylation of amines, which almost cover all the known mechanisms in carbonylation reactions. Notably, the bulk Pd catalyst system exhibited better catalytic activity than the classical homogeneous PdCl2/(2-OMePh)3P catalyst system. This study will create a momentous and new field of green carbonylation reactions.
- Liu, Shujuan,Wang, Hongli,Dai, Xingchao,Shi, Feng
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supporting information
p. 3457 - 3462
(2018/08/06)
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- One-Pot Synthesis of Disubstituted Urea from Carbon Dioxide, Propylene Oxide, and Amines Catalyzed by Imidazolium-Tetraiodoindate
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In this article, synthesis of 1,3-disubstituted urea (DSU) from three component reagent systems comprising amine, carbon dioxide, and propylene oxide is described. DSU is synthesized in the presence of a variety of ionic liquids (ILs) with/without promoters. Among used ILs, 1-butyl-3-methylimidazolium tetraiodoindateIII (represented as [Bmim][InI4]) is found to give the highest DSU product. A serious experiment clearly indicates that the tetraiodoindate anion plays an important role for the selective production of the DSU. Based on the in situ infrared spectroscopic studies, a plausible reaction mechanism for producing dicyclohexylurea from cyclohexylamine is proposed. The synthesis and characterization of [Bmim][InI4] are given in details. Moreover, the effect of reaction variables such as time, temperature, pressure, and the molar ratio of substrate to catalyst is also studied.
- Son, Guang Meang,Truong, Cong Chien,Mishra, Dinesh Kumar,Mishra, Vivek,Kim, Yong Jin
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p. 174 - 183
(2018/01/27)
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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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- Effective approach to ureas through organocatalyzed one-pot process
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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
- Wang, Mingliang,Han, Jilai,Si, Xiaojia,Hu, Yimin,Zhu, Jidong,Sun, Xun
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supporting information
p. 1614 - 1618
(2018/03/28)
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- Chemoselective isocyanide insertion into the N-H bond using iodine-DMSO: Metal-free access to substituted ureas
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Insertion of isocyanides into the N-H bond gives access to many medicinally important and structurally diverse complex nitrogen-containing heterocycles. Although the transition metal catalyzed isocyanide insertion into the N-H bond is very common, polymerization of isocyanides in the presence of a transition metal and their strong coordination with metals are the common drawbacks. On the other hand, the inertness of most of the isocyanides towards amines in the absence of a metal catalyst has stymied the growth of the metal-free approach for isocyanide insertion into amines. As a result, only a handful of metal catalysed methods with limited substrate scopes have been reported for the synthesis of ureas via isocyanide insertion into amines and no metal-free version has been reported yet. Interestingly, chemoselective isocyanide insertion into amines has not been reported in the literature. We employed the I2-DMSO reagent system for the chemoselective synthesis of ureas, where isocyanides react with aliphatic amines only, while aromatic amines need a nucleophilic activator (DABCO) to facilitate the formation of ureas. This method gave direct and chemoselective access to ureas by evading the commonly used yet toxic isocyanates.
- Bora, Porag,Bez, Ghanashyam
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supporting information
p. 8363 - 8366
(2018/08/03)
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- Sulfated polyborate-catalyzed efficient and expeditious synthesis of (un)symmetrical ureas and benzimidazolones
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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.
- Rekunge, Deelip S.,Khatri, Chetan K.,Chaturbhuj, Ganesh U.
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supporting information
p. 4304 - 4307
(2017/10/12)
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- Tuning Synergistic Effect of Au-Pd Bimetallic Nanocatalyst for Aerobic Oxidative Carbonylation of Amines
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The activation and utilization of carbon monoxide is of crucial importance to C1 chemistry. Various catalytic transformation processes have been developed and studied in the last century, and oxidative carbonylation of amines is one of them. Catalysts that have been identified to date for the oxidative carbonylation of amines generally show relatively low activity and/or selectivity. Herein, a metal-organic framework (MOF), i.e., MOF-253 prepared from AlCl3·6H2O and 2,2′-bipyridine-5,5′-dicarboxylic acid, was employed as a support of gold-palladium bimetallic nanoparticles (Au-Pd/MOF) for the oxidative carbonylation of amines under mild conditions. Compared to palladium or gold monometallic catalysts, higher catalytic activity (turnover frequency up to 2573 h-1) and selectivity in the carbonylation of amines were achieved by Au-Pd/MOF bimetallic catalysts through adjusting the molar ratio of gold and palladium within the framework. A breathing effect of Au-Pd/MOF in the catalytic process was further observed from kinetic profiles and powder X-ray diffraction for the first time.
- Duan, Hui,Zeng, Yongfei,Yao, Xin,Xing, Pengyao,Liu, Jia,Zhao, Yanli
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p. 3671 - 3677
(2017/05/01)
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- Ionic liquids/ZnO nanoparticles as recyclable catalyst for polycarbonate depolymerization
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A useful protocol for waste bis-phenol A-polycarbonates (BPA-PC) chemical recycling is proposed based on a bifunctional acid/basic catalyst composed by nanostructured zinc oxide and tetrabutylammonium chloride (ZnO-NPs/NBu4Cl) in quality of Lewis acid and base, respectively. Retro-polymerization reaction proved to be of general application for several nucleophiles, including water, alcohols, amines, polyols, aminols and polyamines, leading to the complete recovery of BPA monomer and enabling the PC polymer to function as a green carbonylating agent (green phosgene alternative) for preparing carbonates, urethanes and ureas. A complete depolymerization can be obtained in seven hours at 100 °C and ZnO nanocatalyst can be recycled several times without sensible loss of activity. Remarkably, when polycarbonate is reacted with glycerol, it is possible to realize in a single process the conversion of two industrial wastes (BPA-PC and glycerol) into two valuable chemicals like BPA monomer and glycerol carbonate (the latter being a useful industrial solvent and fuel additive).
- Iannone, Francesco,Casiello, Michele,Monopoli, Antonio,Cotugno, Pietro,Sportelli, Maria Chiara,Picca, Rosaria Anna,Cioffi, Nicola,Dell'Anna, Maria M.,Nacci, Angelo
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p. 107 - 116
(2016/12/09)
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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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- Novel one-pot synthesis of symmetrically substituted ureas
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We demonstrated a novel, facile, high-yield, and efficient one-pot approach for the synthesis of symmetrically disubstituted ureas from isocyanates in the presence of trimethylsilanol. This novel protocol boasts the use of inexpensive reagents, operational simplicity, excellent yields of products, environmentally friendly conditions, and easy workup. To the best of our knowledge, this is the first example of the synthesis of symmetrically disubstituted ureas from isocyanates in the presence of trimethylsilanol in one pot.
- Wu, Xingxing,Niu, Qingfen,Li, Tianduo
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supporting information
p. 1364 - 1369
(2016/09/03)
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- Preparation method of N,N'-dicyclohexylurea
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The invention discloses a preparation method of N,N'-dicyclohexylurea, and is characterized in that CO2 absorbed by an anionic functionalized ionic liquid through a chemical effect and used as a carbon source and cyclohexylamine are subjected to an in situ reaction to obtain N,N'-dicyclohexylurea under mild conditions. Compared with a traditional method of directly carrying out a reaction of CO2 with cyclohexylamine to prepare N,N'-dicyclohexylurea, the method provided by the invention has the advantages of low reaction temperature and pressure, high CO2 utilization rate, circulative use of the anionic functionalized ionic liquid, and no need for additional addition of a catalyst, a dehydrating agent or a solvent, and is an N,N'-dicyclohexylurea preparation method with industrial application potential.
- -
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Paragraph 0029-0030
(2017/06/02)
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- CeO2-catalyzed direct synthesis of dialkylureas from CO2 and amines
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CeO2 showed higher activity for the direct synthesis of 1,3-dibutylurea (DBU) from CO2 and n-butylamine than the metal oxides tested. The solvent largely influenced the reaction over CeO2, and N-methylpyrrolidone (NMP) was preferable among various solvents tested from the viewpoints of activity and selectivity. The catalyst system composed of CeO2 catalyst and NMP solvent (CeO2 in NMP) was applicable to the reactions of various amines such as linear primary alkylamines or branched primary alkylamines, although tert-butylamine afforded low conversion. In contrast, secondary amines and aniline provided no yield of the ureas. The combination of 2-cyanopyridine with CeO2 in NMP (CeO2 in NMP with 2-cyanopyridine) promoted the transformation of the unreactive amines, showing that tert-butylamine and aniline were converted to the corresponding ureas in 82% and 80% yields, respectively. These yields are much higher than those reported in the previous literatures, indicating that CeO2 in NMP with 2-cyanopyridine drastically promoted transformation of amines with low reactivity.
- Tamura, Masazumi,Ito, Kazuki,Nakagawa, Yoshinao,Tomishige, Keiichi
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- Method for recycling recycled N,N'-dicyclohexylurea
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The invention relates to a method for recycling recycled N,N'-dicyclohexylurea. The method comprises the steps of adding N,N'-dicyclohexylurea and sodium hydroxide into a reaction still, starting stirring, raising temperature to 80-450 DEG C and reacting for 2-8 hours to steam out yielded fluid of cyclohexane in a reaction process. The method has the advantages that the N,N'-dicyclohexylurea of a bio-polypeptide condensing agent by-product is recycled to achieve reclamation of wastes, the problem that the industrialization of the N,N'-dicyclohexylurea is hard to be processed is solved, and the regeneration from the N,N'-dicyclohexylurea to cyclohexylamine to N,N'-dicyclohexylcarbodiimide is achieved, a solvent is not used, and the shortcomings that an organic solvent is flammable and combustible and high in cost are overcome, the yield of the cyclohexylamine is larger than 99%, the purity is larger than 99.3%, raw materials only have the N,N'-dicyclohexylurea and the sodium hydroxide, the products are only cyclohexylamine and sodium carbonate, and the cyclohexylamine and the sodium carbonate can be separated easily. The method is safe and environmentally friendly, low in cost and suitable for industrial production.
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Paragraph 0027
(2016/10/31)
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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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- 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
-
supporting information
p. 212 - 215
(2016/02/03)
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- CO-use CO2 Method for synthesizing N, N - dialkyl oxalate
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The invention provides a method for synthesizing N,N-dialkyl oxamide by using CO2. According to the method, in an organic or inorganic solvent, one-step synthetic reaction is performed on the CO2 and organic amine to synthesize the N,N-dialkyl oxamide, with N,N-dialkyl urea and water as byproducts, in the presence of a certain catalyst and under a certain reaction condition that the reaction pressure is 10-80atm and the reaction temperature is 100-200 DEG C. The invention discloses the method for synthesizing the N,N-dialkyl oxamide by using the CO2. According to the method, a valuable and toxic metal catalyst and a toxic and explosive gas in the prior art are not used, and reactants, products, and added components in a system are safe and environment-friendly; the yield is considerable; technically, an improvement room exists; a safe and environment-friendly new method is provided for preparing the N,N-dialkyl oxamide.
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Paragraph 0042; 0043; 0044; 0045; 0046
(2016/11/17)
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- A ruthenium racemisation catalyst for the synthesis of primary amines from secondary amines
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A Ru-based half sandwich complex used in amine and alcohol racemization reactions was found to be active in the splitting of secondary amines to primary amines using NH3. Conversions up to 80% along with very high selectivities were achieved. However, after about 80% conversion the catalyst lost activity. Similar to Shvo's catalyst, the complex might deactivate under the influence of ammonia. It was revealed that not NH3 but mainly the primary amine is responsible for the deactivation.
- Pingen, Dennis,Altinta?, ?i?dem,Rudolf Schaller, Max,Vogt, Dieter
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supporting information
p. 11765 - 11771
(2016/07/28)
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- Iron-catalyzed reaction of urea with alcohols and amines: A safe alternative for the synthesis of primary carbamates
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A general study of the iron-catalyzed reaction of urea with nucleophiles is here presented. The carbamoylation of alcohols allows for the synthesis of N-unsubstituted (primary) carbamates, including present drugs (Felbamate and Meprobamat, without the necessity to apply phosgene and related derivatives. Using amines as nucleophiles gave rise to the respective mono-and disubstituted ureas via selective transamidation reaction. These atom-economical transformations provide a direct and selective access to valuable compounds from cheap and readily available urea using a simple Lewis-acidic iron(Icatalyst.
- Pe?a-López, Miguel,Neumann, Helfried,Beller, Matthias
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p. 2233 - 2238
(2017/07/25)
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- Designing of thermally stable amide functionalized benzimidazolium perchlorate ionic liquid for transamidation of primary carboxamides
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In the present work, we have designed and synthesized a thermally stable catalyst based on functionalized benzimidazolium perchlorate ionic liquid and tested its efficacy towards metal free and solvent free transamidation of amides and amines. The ionic liquid comprising the perchlorate ion has shown remarkably better activity than those which contain other anions and accordingly a plausible mechanism for the catalytic activity is arrived. The developed catalytic system has shown excellent activity towards the transamidation of alicyclic and aromatic amines with acetamide, benzamide and p-nitrobenzamide under mild conditions. Furthermore, the transamidation of nicotinamide with benzylamine in presence of the ionic liquid catalyst was found to occur with very good yields and thus provides a facile route for the synthesis of pharmaceutically significant compounds. The catalyst has exhibited very good thermal stability upto 203 °C and very good recyclability upto 5 runs without significant loss in its activity.
- Muskawar, Prashant Narayan,Thenmozhi,Bhagat, Pundlik Rambhau
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p. 158 - 167
(2015/09/28)
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- Process for preparing N,N'-substituted urea derivatives using cerium dioxide catalyst
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Cerium oxide and amine derivatives the present invention refers to the presence of a catalyst characterized by N signals from the video signals from the, N '-substituted fabric sheet winding relates to manufacturing method. In the present invention a high quality catalytic component, cerium oxide, amine compound in an atmosphere in carbon dioxide gas starting from the carboxylated the reaction takes place in the by N for high yield according to the reaction condition, N '-substituted urea forming the, after catalyst used may be reused the ease of separating the..
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Paragraph 0037; 0045-0047
(2017/01/02)
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- By fixing carbon dioxide production of alkylurea compd.
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PROBLEM TO BE SOLVED: To provide a method for preparing a urea compound by fixing carbon dioxide. SOLUTION: This invention relates to a method for preparing the urea compound by reacting a carbon dioxide raw material with an amine compound raw material by a reaction system with a medium containing at least carbon dioxide as a reaction medium, chemically fixing carbon dioxide to the amine compound, and synthesizing the urea compound corresponding to the amine compound raw material. This invention also relates to a method for preparing the urea compound by synthesizing the urea compound corresponding to the amine compound with water in which carbon dioxide is dissolved or carbon dioxide containing water as the reaction medium. According to this invention, the corresponding urea compound can be synthesized at a high selection rate from the amine compound by the carbon dioxide fixation process. COPYRIGHT: (C)2012,JPOandINPIT
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Paragraph 0050; 0051
(2016/11/14)
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- Facile synthesis of 1-trifluoromethylalkenes via the decarboxylation of α-trifluoromethyl-β-lactones
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DCC-mediated cyclodehydration of α-trifluoromethyl-β-hydroxy acids provides α-trifluoromethylated β-lactone intermediates, without loss of stereoselectivity. These lactones undergo facile decarboxylation providing a simple route to obtain both alkyl and aryl trifluoromethylated alkenes in excellent yields and stereoselectivity.
- Veeraraghavan Ramachandran,Otoo, Barnabas
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p. 12388 - 12390
(2015/08/03)
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- Copper(II)-catalysed oxidative carbonylation of aminols and amines in water: A direct access to oxazolidinones, ureas and carbamates
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Copper(II) chloride catalyses the oxidative carbonylation of aminols, amine and alcohols to give 2-oxazolidinones, ureas and carbamates. Reaction proceeds smoothly in water under homogeneous conditions (Ptot = 4 MPa; PO2 = 0.6 MPa, PCO), at 100°C in relatively short reaction times (4 h) and without using bases or any other additives. This methodology represents an economic and environmentally benign non-phosgene alternative for the preparation of these three important N-containing carbonyl compounds.
- Casiello, Michele,Iannone, Francesco,Cotugno, Pietro,Monopoli, Antonio,Cioffi, Nicola,Ciminale, Francesco,Trzeciak, Anna M.,Nacci, Angelo
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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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- Selective N-methylation of aliphatic amines with CO2 and hydrosilanes using nickel-phosphine catalysts
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A method using CO2 and PhSiH3 for the methylation of primary and secondary aliphatic amines catalyzed by Ni (0) complexes was developed, selectively producing the monomethylated products in moderate to good yields. For that purpose, two catalysts were used: [(dippe)Ni(μ-H)]2 and the commercially available Ni(COD)2/dcype, both of which were rather efficient in this process. With a slight experimental modification, the reaction allowed the production of monomethylated ureas in good yields by using low amounts of PhSiH3. On the basis of the experimental results, we propose a possible reaction mechanism for the formation of the new C-N bond.
- Gonzlez-Sebastin, Lucero,Flores-Alamo, Marcos,Garca, Juventino J.
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p. 763 - 769
(2015/05/12)
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- Process for Preparing Disubstituted Urea and Carbamate Compounds from Amines, Carbon Dioxide, and Epoxides
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The present disclosure relates to a method for preparing a disubstituted urea and carbamate compounds simultaneously through a one-pot reaction of an amine, carbon dioxide and an alkylene oxide compound in the presence of an ionic liquid-based complex catalyst system containing indium. In accordance with the present disclosure, a disubstituted urea and carbamate compounds can be prepared simultaneously at high yield. In addition, the ionic liquid-based catalyst containing indium according to the present disclosure is economical because it can be reused several times.
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Paragraph 0061; 0062
(2015/05/26)
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