1461-81-0Relevant academic research and scientific papers
A new practical method for the synthesis of unsymmetrical ureas via high-pressure-promoted condensation of 2,2,2-trichloroethyl carbamates (Troc-carbamates) with amines
Azad, Saleha,Kumamoto, Koji,Uegaki, Kaoru,Ichikawa, Yoshiyasu,Kotsuki, Hiyoshizo
, p. 587 - 590 (2006)
A new practical method for the synthesis of unsymmetrical ureas was achieved by condensation between 2,2,2-trichloroethyl carbamates (Troc-carbamates) and primary or secondary amines under high-pressure conditions.
A Fe3O4?SiO2/Schiff Base/Pd Complex as an Efficient Heterogeneous and Recyclable Nanocatalyst for One-Pot Domino Synthesis of Carbamates and Unsymmetrical Ureas
Inaloo, Iman Dindarloo,Majnooni, Sahar
, p. 6359 - 6368 (2019/11/05)
A palladium-catalyzed domino method for the direct synthesis of carbamates and ureas has been developed by using readily available and economical starting materials (aryl halide, carbon monoxide, sodium azide, amines and alcohols) in a one-pot approach. The domino process underwent carbonylation, Curtius rearrangement, and nucleophilic addition. This protocol provides a step-economical and highly efficient reaction to access the wide range of valuable carbamates, symmetrical and unsymmetrical ureas with high yields under remarkable mild reaction conditions that are important factors in pharmaceutical science, biochemistry and agricultural industries. Furthermore, the magnetically recoverable nanocatalyst (Fe3O4?SiO2/Pd(II)) can be conveniently and swiftly recycled using external magnet and reused at least for seven times without noticeable loss of its catalytic activity.
Iron(II)-Catalyzed Hydroamination of Isocyanates
South, Amy J.,Geer, Ana M.,Taylor, Laurence J.,Sharpe, Helen R.,Lewis, William,Blake, Alexander J.,Kays, Deborah L.
supporting information, p. 4115 - 4120 (2019/10/17)
A two-coordinate Fe(II) m-terphenyl complex acts as a precatalyst for the hydroamination of isocyanates, affording urea and biuret derivatives, with product selectivity accomplished via modification of the reaction conditions. Using a more nucleophilic amine facilitates the insertion of up to four isocyanates into the N-H bond, affording triuret and tetrauret derivatives.
Efficient Direct Halogenation of Unsymmetrical N -Benzyl- and N -Phenylureas with Trihaloisocyanuric Acids
Sanabria, Carlos M.,Costa, Bruno B. S.,Viana, Gil M.,De Aguiar, Lúcia C. S.,De Mattos, Marcio C. S.
supporting information, p. 1359 - 1367 (2017/12/26)
A simple and efficient methodology for the direct halogenation of N -phenylureas was developed using trihaloisocyanuric acids in acetonitrile at room temperature. This protocol proved to be effective for the construction of N -phenylureas with different patterns of substitution. Additionally, less reactive N -benzylureas were halogenated in the presence of a mixture of trifluoroacetic acid and acetonitrile at room temperature.
2-Picolylamino(diphenylphosphinoselenoic)amide supported zinc complexes: Efficient catalyst for insertion of N–H bond into carbodiimides, isocyanates, and isothiocyanate
Harinath, Adimulam,Bano, Kulsum,Ahmed, Shakil,Panda, Tarun K.
supporting information, p. 23 - 32 (2017/09/25)
We report here the hydroamination of heterocumulenes such as carbodiimides, isocyanates, and isothiocyanates by zinc complexes supported by the ligand 2-picolylamino-(diphenylphosphinoselenoic)amide [{(Ph2P-(?Se)}2NCH2(C5H4N)] (1). A series of zinc complexes [κ2-{(Ph2P-(?Se)}2NCH2(C5H4N)ZnX2] [(X?Cl (2), Br (3a), I (4)] were prepared from ligand 1 and the corresponding zinc dihalide in a 1:1 molar ratio at 60°C in a chloroform solvent. The reaction of ligand 1 and ZnBr2 in methanol yielded another zinc complex [κ2-{(Ph2P-(?Se)}2NCH2(C5H4N)ZnBr2(CH3OH)] (3b). The molecular structures of compounds 3a, 3b, and 4 were established through single-crystal X-ray diffraction analyses. The solid-state structures of all the complexes revealed a κ2- chelation through pyridine nitrogen and selenium atoms of ligand 1 to the zinc ion. Complex 2 proved to be a competent pre-catalyst for the addition of the amine N–H bond to carbodiimides, isocyanates, and isothiocyanates. The reaction scope was expanded to reactions of aliphatic and aromatic amines with phenylisocyanate and phenylisothiocyanate in toluene solvents, which proceeded rapidly at room temperature with 5 mol% catalyst loading to yield (up to 99%) the corresponding derivatives of urea and thio-urea. However, a temperature of 90°C was needed for the hydroamination of N,N′ dicyclohexylcarbodiimide. We also report the most plausible mechanism of the hydroamination reaction.
Highly Regioselective Iodination of N-Phenylureas with Iodine/Trichloroisocyanuric Acid
Sanabria, Carlos M.,do Casal, Mariana T.,De Souza, Raphael B. A.,De Aguiar, Lúcia C. S.,De Mattos, Marcio C. S.
supporting information, p. 1648 - 1654 (2017/03/21)
An efficient regioselective iodination of N-phenylureas was developed using iodine/trichloroisocyanuric acid in acetonitrile at room temperature. This protocol proved to be effective on a broad range of substituted N-phenylureas, forming the p-iodinated compounds in 65-96% yield under mild and neutral conditions.
Synthesis of ureas in the bio-alternative solvent Cyrene
Mistry, Liam,Mapesa, Kopano,Bousfield, Thomas W.,Camp, Jason E.
supporting information, p. 2123 - 2128 (2017/07/24)
Cyrene as a bio-alternative solvent: a highly efficient, waste minimizing protocol for the synthesis of ureas from isocyanates and secondary amines in the bio-available solvent Cyrene is reported. This method eliminated the use of toxic solvents, such as
A facile method for the preparation of unsymmetrical ureas utilizing zirconium (IV) chloride
Lee, Anna,Kim, Hee-Kwon,Thompson, David H.
, p. 154 - 160 (2016/02/26)
A facile synthetic method for the preparation of unsymmetrical ureas from amines is described. Carbamoyl imidazole compounds were prepared by the reaction of 1, 1-carbonyldiimidazole with primary or secondary amines, and further activation by treatment with zirconium(IV) chloride to generate the desired urea. This reaction protocol was applied to the synthesis of tri and tetrasubstituted ureas with high yields. This study provides an alternative guideline for the practical preparation of various unsymmetrical ureas.
Hydroamination of carbodiimides, isocyanates, and isothiocyanates by a bis(phosphinoselenoic amide) supported titanium(IV) complex
Bhattacharjee, Jayeeta,Das, Suman,Kottalanka, Ravi K.,Panda, Tarun K.
supporting information, p. 17824 - 17832 (2016/11/18)
The hydroamination of heterocumulenes such as carbodiimides, isocyanates, and isothiocyanates by a bis(phosphinoselenoic amide) supported titanium(iv) complex as a precatalyst is reported here. The titanium(iv) complex [{Ph2P(Se)NCH2CH2NPPh2(Se)}Ti(NMe2)2] (1) was synthesised by the reaction of tetrakis-(dimethylamido)titanium(iv) [Ti(NMe2)4] with [{Ph2P(Se)NHCH2CH2NHPPh2(Se)}] in toluene at ambient temperature. Titanium complex 1 proved to be a competent pre-catalyst for the addition of an amine N-H bond to carbodiimides, isocyanates, and isothiocyanates. The reaction scope was expanded to reactions of aliphatic and aromatic amines with phenylisocyanates and phenylisothiocyanates in toluene solvents proceeding rapidly at room temperature with 5 mol% catalyst loadings to yield the corresponding urea and thio-urea derivatives up to 99%. However, ambient temperature was needed for hydroamination of 1,3-dicyclohexylcarbodiimide. The amine addition reactions with isocyanates showed first order kinetics with respect to catalyst 1 as well as substrates. The most plausible mechanism for the hydroamination reaction was established by isolating 1,1-dimethylphenyl urea as a side product.
Imidazolin-2-iminato Ligand-Supported Titanium Complexes as Catalysts for the Synthesis of Urea Derivatives
Naktode, Kishor,Das, Suman,Bhattacharjee, Jayeeta,Nayek, Hari Pada,Panda, Tarun K.
supporting information, p. 1142 - 1153 (2016/02/09)
The reactions of tetrakis(dimethylamido)titanium(IV) [Ti(NMe2)4] with three different imidazolin-2-imines (ImRNH; R = tert-butyl (tBu), mesityl (Mes), and 2,6-diisopropylphenyl (Dipp)) afforded the corresponding titanium i
