1007-36-9Relevant academic research and scientific papers
Chloromethylated polystyrene immobilized ruthenium complex of 2-(2-pyridyl)benzimidazole catalyst for the synthesis of bioactive disubstituted ureas by carbonylation reaction
Dey, Tusar Kanto,Ghosh, Kajari,Basu, Priyanka,Molla, Rostam Ali,Islam, Sk. Manirul
, p. 9168 - 9176 (2018)
Polymer supported transition metal complex catalysts have numerous applications as heterogeneous catalysts due to their ease of synthesis and commercial availability. Ru-Py-Merf was synthesized by anchoring 2-(2-pyridyl)benzimidazole to the polymer matrix, followed by loading of ruthenium salt. This Ru-Py-Merf material was thoroughly characterized by FTIR spectroscopy, UV-vis absorption spectroscopy, FE-SEM analysis, EDAX analysis, CHN analysis, AAS spectroscopy and TGA. Ru-Py-Merf showed excellent catalytic activity in the synthesis of symmetric and asymmetric disubstituted ureas by reductive carbonylation of nitrobenzenes and anilines. The as-synthesized Ru-Py-Merf catalyst is entirely heterogeneous in nature, thermally stable and can be easily reused up to six times.
Synthesis and architecture of polystyrene-supported Schiff base-palladium complex: Catalytic features and functions in diaryl urea preparation in conjunction with Suzuki-Miyaura cross-coupling reaction by reductive carbonylation
Basu, Priyanka,Riyajuddin, Sk,Dey, Tusar Kanto,Ghosh, Aniruddha,Ghosh, Kaushik,Islam, Sk Manirul
, p. 37 - 50 (2018)
This work represents an efficient and unique phosphine-free approach for the polystyrene embedded Schiff-base palladium catalyzed diaryl urea synthesis and Suzuki-Miyaura cross-coupling reaction by reductive carbonylation process. The careful instrumental investigations with FE-SEM, TEM, EDAX, TGA, UV–Vis, FTIR, AAS, and elemental analysis precisely characterized the developed heterogeneous catalyst. Reaction parameters, like catalytic natures, starting materials, reaction environment, and solvent were examined sequentially. The present work has been adequately addressed to account for the generation and characterization of a new polymer bound Pd-catalyst and using it in the synthesis of diaryl ureas and diaryl ketones, with no substantial decay of catalytic activity.
Reaction of β-Nitro Enamines with Isocyanates, Isothiocyanates and Dimethyl Acetylenedicarboxylate
Tokumitsu, Takao
, p. 3871 - 3876 (1986)
β-Nitro enamines (1) reacted with isocyanates and isothiocyanates to give β-(substituted carbamoyl) and β-(substituted thiocarbamoyl) β-nitro enamines, respectively.The reaction of 1 with benzoyl isothiocyanate gave β-(benzoylthiocarbamoyl) β-nitro enamines (8) and/or a mixture of 8 and 4(1H)-pyrimidinethione derivatives (9), which were cyclization products of 8.The isolated 8 afforded the corresponding 9 in high yields upon heating in DMF.The reaction of 1 with dimethyl acetylenedicarboxylate gave cycloadducts (12) and/or a mixture of 12 and δ-nitro dienamino diesters (13) which were ring cleavage products of 12.Compounds 12 afforded 13 upon heating in toluene or xylene.
Splitting a Substrate into Three Parts: Gold-Catalyzed Nitrogenation of Alkynes by C-C and C≡C Bond Cleavage
Qin, Chong,Su, Yijin,Shen, Tao,Shi, Xiaodong,Jiao, Ning
, p. 350 - 354 (2016/01/25)
A gold-catalyzed nitrogenation of alkynes for the synthesis of carbamides and amino tetrazoles through C-C and C≡C bond cleavages is described. A diverse set of functionalized carbamide and amino tetrazole derivatives were selectively constructed under mild conditions. The chemoselectivity can be easily switched by the selection of the acid additives. The reaction is characterized by its broad substrate scope, direct construction of high value products, easy operation under air, and mild conditions at room temperature. This chemistry provides a way to transform alkynes by splitting the substrate into three parts.
Microwave-assisted synthesis of symmetrical and unsymmetrical N,N 0-disubstituted thioureas and ureas over MgO in dry media
Valizadeh, Hassan,Dinparast, Leila
experimental part, p. 251 - 254 (2012/07/01)
Under mild microwave irradiation conditions a variety of symmetrical and unsymmetrical A,N′-disubsti-tuted thioureas and ureas were prepared via the reaction of Af-monosubstituted hydroxylamines with isocyanate and isothiocyanate derivatives over MgO under solvent-free conditions. This new method afforded satisfactory results with good yields, short reaction time, and simplicity in the experimental procedure.
The vinyl moiety as a handle for regiocontrol in the preparation of unsymmetrical 2,3-aliphatic-substituted indoles and pyrroles
Huestis, Malcolm P.,Chan, Lina,Stuart, David R.,Fagnou, Keith
supporting information; experimental part, p. 1338 - 1341 (2011/04/21)
Rho-Rho-Rho your boat: A rhodium catalyst effects the regioselective oxidative coupling of enynes with N-aryl ureas (X=NR2) and N-vinylacetamides (X=C(O)Me), affording the corresponding 2-alkenylindoles and 2-alkenylpyrroles in good yield. Simple hydrogenation delivers the C2/C3-aliphatic-substituted indole or pyrrole (see scheme).
Intramolecular hydrogen bonding in medicinal chemistry
Kuhn, Bernd,Mohr, Peter,Stahl, Martin
supporting information; experimental part, p. 2601 - 2611 (2010/08/05)
The formation of intramolecular hydrogen bonds has a very pronounced effect on molecular structure and properties. We study both aspects in detail with the aim of enabling a more rational use of this class of interactions in medicinal chemistry. On the basis of exhaustive searches in crystal structure databases, we derive propensities for intramolecular hydrogen bond formation of five- to eight-membered ring systems of relevance in drug discovery. A number of motifs, several of which are clearly underutilized in drug discovery, are analyzed in more detail by comparing small molecule and protein-ligand X-ray structures. To investigate effects on physicochemical properties, sets of closely related structures with and without the ability to form intramolecular hydrogen bonds were designed, synthesized, and characterized with respect to membrane permeability, water solubility, and lipophilicity. We find that changes in these properties depend on a subtle balance between the strength of the hydrogen bond interaction, geometry of the newly formed ring system, and the relative energies of the open and closed conformations in polar and unpolar environments. A number of general guidelines for medicinal chemists emerge from this study
Flash vacuum pyrolysis of 1,2,5-oxadiazole 2-oxides and 1,2,3-triazole 1-oxides
Mitchell, William R.,Paton, R. Michael
experimental part, p. 34 - 54 (2011/02/21)
The flash vacuum pyrolysis (FVP, 450-600 °C/10-3 mmHg) of 3,4-diaryl- and 3,4-dialkyl-1,2,5-oxadiazole 2-oxides (furoxans) has been investigated. In all cases the 1,2,5-oxadiazole ring cleaved cleanly at O(1)-N(2) and C(3)-C(4) to afford two nitrile oxide fragments, which were trapped in high yield (75-97%) as their isoxazoline cycloadducts by reaction with alk-1-enes. At higher temperatures (700-800 °C) isocyanates were formed as by-products. The dimerisation of acetonitrile oxide to dimethylfuroxan was followed by 1H NMR spectroscopy, and the rate constant for the 2 nd order reaction determined. The furoxans were converted into isocyanates in good yield (61-95%) by FVP, followed by sulfur dioxide-mediated isomerisation of the resulting nitrile oxides. 2,4,5-Trisubstituted-1,2,3- triazole 1-oxides showed greater thermal stability, but at 700-800 °C decomposition of the 4,5-dimethyl compound 25b lead to 1,2-di(5-methyl-2-phenyl- 1,2,3-triazol-2-yl)ethane as the major product; attempts to trap acetonitrile oxide were unsuccessful. ARKAT USA, Inc.
Synthesis and anticonvulsant activity of new N-1′,N-3′-disubstituted-2′H,3H,5′H-spiro-(2-benzofuran-1,4′-imidazolidine)-2′,3,5′-triones
Patel, Hardik J.,Sarra, Joe,Caruso, Francesco,Rossi, Miriam,Doshi, Utkarsh,Stephani, Ralph A.
, p. 4644 - 4647 (2007/10/03)
Thirteen new N-1′,N-3′-disubstituted-2′H,3H,5′H-spiro-(2-benzofuran-1,4′-imidazolidine)-2′,3,5′-triones were synthesized and their pharmacological activity determined with the objective to better understand their SAR for anticonvulsant activity. The anticonvulsant effects of these compounds were evaluated by standard pentylenetetrazol (scPTZ test) and maximum electroshock seizure (MES test) models in mice. Most of the compounds showed ability to protect against the pentylenetetrazol-induced convulsions. Compound 3o (the N-1′-p-nitrophenyl, N-3′-ethyl derivative) in the N-1′-aryl, N-3′-alkyl disubstituted series exhibited maximum activity with ED50 of 41.8 mg/kg in scPTZ convulsion model.
Synthesis and characterisation of platinum(II) ureylene complexes, and the X-ray structure of [Pt{PhNC(O)NAd}(COD)] (Ad = 1-adamantyl, COD = 1,5-cyclo-octadiene)
Dinger, Maarten B.,Henderson, William,Nicholson, Brian K.,Wilkins, Alistair L.
, p. 303 - 312 (2007/10/03)
Reaction of [PtCl2(COD)] or cis-[PtCl2(PPh3)2] with a range of mono-and di-substituted ureas, together with urea itself, and an excess of silver(I) oxide gives ureylene complexes 3 and 4 containing the Pt-N-C(O)
