- An efficient one-pot synthesis of industrially valuable primary organic carbamates and: N -substituted ureas by a reusable Merrifield anchored iron(ii)-anthra catalyst [FeII(Anthra-Merf)] using urea as a sustainable carbonylation source
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An efficient synthesis of primary carbamates and N-substituted ureas is explored with a newly developed heterogeneous polymer supported iron catalyst in the presence of a sustainable carbonylation source. The Merrifield anchored iron(ii)-anthra catalyst [FeII(Anthra-Merf)] was synthesized by functionalization of Merrifield polymer followed by grafting of iron metal. The catalyst [FeII(Anthra-Merf)] was characterized by several techniques, like SEM, EDAX, TGA, PXRD, XPS, FTIR, CHN, AAS and UV-Vis analysis. The designed polymer embedded [FeII(Anthra-Merf)] complex is a remarkably successful catalyst for the synthesis of primary organic carbamates and N-substituted ureas by using safe carbonylation agent urea with different derivatives of alcohols and amines, respectively. The reported catalyst is a potential candidate towards contributing a satisfactory yield of isolated products under suitable reaction conditions. The catalyst is recyclable and almost non-leaching in nature after six runs with an insignificant drop in catalytic activity. Thus we found an economical and viable catalyst [FeII(Anthra-Merf)] for primary carbamates and N-substituted urea synthesis under moderate reaction conditions.
- Basu, Priyanka,Dey, Tusar Kanto,Ghosh, Aniruddha,Biswas, Surajit,Khan, Aslam,Islam, Sk. Manirul
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p. 2630 - 2643
(2020/02/20)
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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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- One-pot, solvent-free access to unsymmetrical ureas by palladium-catalysed reductive alkylation using molecular hydrogen
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Palladium-catalysed reductive alkylation of monosubstituted ureas has been studied in the presence of aldehydes and using molecular hydrogen as a clean reductant. Unsymmetrical N,N′-disubstituted ureas were formed in good to excellent isolated yields (60-93 %) without the production of salt waste. This reaction was incorporated to a one-pot, solvent-free sequence involving the alkylation of monosubstituted ureas generated in situ from the corresponding amines. Unsymmetrical N,N′-disubstituted ureas were prepared in 60-93 % isolated yield by palladium-catalysed reductive alkylation of monosubstituted ureas using aldehydes as alkylating agents and molecular hydrogen as a clean reductant. A one-pot, solvent-free sequence was also developed from the corresponding amines. Copyright
- Mohy El Dine, Tharwat,Chapron, Simon,Duclos, Marie-Christine,Duguet, Nicolas,Popowycz, Florence,Lemaire, Marc
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p. 5445 - 5454
(2013/09/02)
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- Transamidation of primary amides with amines catalyzed by zirconocene dichloride
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Zirconocene dichloride (Cp2ZrCl2) has been shown to be an effective catalyst for the transamidation of primary amides with amines in cyclohexane at 80°C in 5-24 hours. For favourable substrates, the reaction can be performed at temperatures as low as 30°C.
- Atkinson, Benjamin N.,Chhatwal, A. Rosie,Lomax, Helen V.,Walton, James W.,Williams, Jonathan M. J.
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supporting information
p. 11626 - 11628,3
(2012/12/12)
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- Transamidation of primary amides with amines catalyzed by zirconocene dichloride
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Zirconocene dichloride (Cp2ZrCl2) has been shown to be an effective catalyst for the transamidation of primary amides with amines in cyclohexane at 80°C in 5-24 hours. For favourable substrates, the reaction can be performed at temperatures as low as 30°C.
- Atkinson, Benjamin N.,Chhatwal, A. Rosie,Lomax, Helen V.,Walton, James W.,Williams, Jonathan M. J.
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supporting information
p. 11626 - 11628
(2013/01/15)
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- A convenient, one-step synthesis of benzyl (Ar) ureas of the type ArCH 2NHCONHR from Ar and R1OCH2NHCONHR via ureidoalkylation
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A method for the one-step C-ureidoalkylation of phenol, anisole, or aniline rings furnishing ArCH2NHCONHR (Ar ) benzyl) products in moderate to good yields is described. With phenol ring systems, higher yields were attained when the reaction was worked up with an acidic ethanethiol addition to cleave any O-ureidoalkylation products that formed during the reaction.
- Meece, F. Alex,Jayasinghe, Champika,Histand, Gary,Burns, Dennis H.
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supporting information; experimental part
p. 3156 - 3159
(2009/09/05)
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- Preparation of mono-, di-, and trisubstituted ureas by carbonylation of aliphatic amines with S,S-dimethyl dithiocarbonate
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General procedures are reported to prepare N-alkylureas, N,N′-dialkylureas (both symmetrical and unsymmetrical), and N,N,N′-trialkylureas by carbonylation of aliphatic amines, employing S,S-dimethyl dithiocarbonate (DMDTC) as a phosgene substitute. All reactions were carried out in water. Symmetrical disubstituted ureas were prepared directly working at 60°C with a molar ratio of DMDTC:amine = 1:2, preferably under nitrogen. Unsymmetrical ureas were prepared in two steps via S-methyl N-alkyl-thiocarbamate intermediates, which are formed selectively in the first step at room temperature. These intermediates react in the second step with ammonia or various aliphatic amines, both primary and secondary, at temperatures varying between 50 and 70°C. All the target ureas were obtained in high yields (28 examples, average yield 94%) and with very high purity (generally >99.2%). Also to be noted is the recovery of a co-product of industrial interest, methanethiol, in an amount of two moles for each mole of DMDTC, with complete exploitation of the reagent. Georg Thieme Verlag Stuttgart.
- Artuso, Emma,Degani, Iacopo,Fochi, Rita,Magistris, Claudio
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p. 3497 - 3506
(2008/09/19)
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- Process for the N-alkylation or ureas
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Process for the N-alkylation of ureas by reacting a urea with an alkylating agent in the presence of a solid base and a phase transfer catalyst in a diluent.
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- The Synthesis of N-Substituted Ureas I: The N-Alkylation of Ureas
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Urea and N-alkylureas are N'-alkylated in low yields using aprotic dipolar solvents, like dimethylsulfoxide, solid potassium hydroxide, and alkyl halides.Phase transfer catalysis with tetrabutylammonium chloride in refluxing toluene results in high yield
- Hackl, Kurt A.,Falk, Heinz
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p. 599 - 606
(2007/10/02)
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- Process for the preparation of asymmetrically substituted ureas
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Process for the preparation of asymmetrically substituted ureas by reaction of a gaseous mixture of isocyanic acid and ammonia having a temperature of 260° to 600° C. with a primary or secondary amine.
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- Some Extensions of von Braun (BrCN) Reaction on Organic Bases, Part IV
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Extensions of von Braun cyanogen bromide reaction have been undertaken on some aliphatic and heterocyclic amines.Monocyanamides of all these bases yielded their respective urea and carboxamide derivatives on hydrolysis with dilute hydrochloric acid.They also gave the amido derivatives on reaction with Zn/HCl, as in the case of diisobutyl and di-2-butyl cyanamides. - Key words: von Braun Cyanogen Bromide Reaction
- Siddiqui, Salimuzzaman,Haider, S. Imtiaz,Ahmad, S. Salman,Siddiqui, B. Shaheen
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p. 546 - 549
(2007/10/02)
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- Process for reacting chloral with nitrogen compositions
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A flame retardant composition is prepared by reacting chloral with a nitrogen compound having the formula: STR1 wherein: (a) X= STR2 or, --SO2 --; (b) Z is selected from O or S; (c) R1, R2, R3 and R4 are selected from the group consisting of H, alkyl of 1 to 6 carbons, and substituted or unsubstituted hydroxyalkyl of 2 to 4 carbons and mixtures thereof in a temperature range of 25° to 100° C., in the absence of a solvent and in an apparatus that provides efficient mixing. These compositions are useful for preparing flame retardant polyurethane foams.
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