621-04-5Relevant academic research and scientific papers
Stabilization of the hindered urea bond through de-tert-butylation
Yang, Yingfeng,Ying, Hanze,Jia, Yunchao,Chen, Yingying,Cheng, Jianjun
supporting information, p. 3812 - 3815 (2021/04/21)
We report the discovery of an acid-assisted de-tert-butylation reaction that can instantly “turn off” the dynamicity of hindered urea bonds (HUBs) and thus broaden their applications. The reaction is demonstrated to be widely applicable to different hindered urea substrates, leading to improved chemical stabilities and mechanical properties of HUB-containing materials.
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.
Copper-catalyzed domino reaction of carbodiimides and benzoic acid derivatives for the synthesis of quinazolinediones
Duangjan, Chanikan,Rukachaisirikul, Vatcharin,Saithong, Saowanit,Kaeobamrung, Juthanat
supporting information, p. 3537 - 3540 (2018/08/29)
Quinazolinediones were obtained from 2-iodobenzoic acids and carbodiimide derivatives under mild reaction conditions via a copper-catalyzed domino reaction. The absence of an external base was essential to avoid the generation of amide by-products. Both alkyl- and aryl-substituted carbodiimides gave the corresponding quinazolinediones. However, the use of aryl-substituted carbodiimides resulted in low yields due to an undesired elimination process.
A synthetic N, N '-di-substituted ureas method
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Paragraph 0075-0078, (2016/11/17)
The invention discloses a method for synthesizing N,N'-disubstituent urea. The method comprises the following steps: adding N-substituent urea, a metal iridium, rhodium or ruthenium complex catalyst, an alkali, a compound alcohol and a solvent (or no solvent) to a reaction container; reacting at 90-130 DEG C for a plurality of hours and cooling the reaction mixture to room temperature; carrying out rotary evaporation to remove the solvent, and then separating through a column, so as to obtain a target compound. Compared with the prior art, N,N'-disubstituent urea which is obtained by regional selective alkylation reaction between commercial or easily synthesized N-substituent urea and the alcohol reflects and displays three significant advantages: 1) the alcohol which is nearly non-toxic is utilized as an alkylating reagent; 2) just water is generated as a by-product in the reaction, and harm to environment is not generated; 3) reaction atom economy is high. Therefore, the reaction accords with the requirements of green chemistry, and has a broad development prospect.
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.
Efficient copper(II)-catalyzed transamidation of non-activated primary carboxamides and ureas with amines
Zhang, Min,Imm, Sebastian,Baehn, Sebastian,Neubert, Lorenz,Neumann, Helfried,Beller, Matthias
, p. 3905 - 3909 (2012/06/04)
Amid(e) them all: Primary carboxamides and ureas react with aromatic and aliphatic amines in the presence of a copper catalyst to give a wide range of functionalized amides (see scheme). Copyright
Iron(II)-catalyzed oxidation of sp3 C-H bonds adjacent to a nitrogen atom of unprotected arylureas with tert-butyl hydroperoxide in water
Wei, Ying,Ding, Hongqian,Lin, Shaoxia,Liang, Fushun
supporting information; experimental part, p. 1674 - 1677 (2011/05/13)
With a FeSO4/TBHP system in water, direct oxidation of sp 3 C-H bonds adjacent to nitrogen of arylureas to give both unprecedented tert-butoxylated and hydroxylated products 2 was revealed. Under elevated temperatures, either 2-oxo-N-arylpyrrolidine-1-carboxamides 3 or 1,3-diarylureas 4 were attained, depending on the aliphatic ring size of the arylurea substrates.
The preparation and characterization of nineteen new phthalidyl spirohydantoins
Lengyei, Istvan,Patel, Hardik J.,Stephani, Ralph A.
experimental part, p. 349 - 375 (2009/09/08)
Abstract - Nineteen new N,N-disubstituted phthalidyl spirohydantoins (6a-s) were prepared for the purpose of pharmacological testing. Their structure was deduced from the IR, 1H-NMR, 13C-NMR, mass spectra and elemental analysis. The two possible structural isomers - only one of which is formed - can be distinguished unequivocally on the basis of selective diastereotopicity of the α-methylene hydrogens adjacent to N-3′ of the hydantoin ring.
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.
Phenylureas. Part 1. Mechanism of the basic hydrolysis of phenylureas
Laudien,Mitzner
, p. 2226 - 2229 (2007/10/03)
The mechanism of the hydrolytic decomposition of phenylureas in basic media in the pH range 12 to 14 is investigated. In this pH range a levelling of the rate-pH curve is observed as well as a change of the substituent influence on the hydrolysis rate. These experimental findings suggest the formation of an unreactive side product of the phenylurea in a parasitic side equilibrium at sufficiently high pH. The urea dissociates at the aryl-NH group to give its conjugate base. For the hydrolytic decomposition of phenylureas an addition-elimination mechanism is proposed as has been established for the alkaline hydrolysis of carboxylic acid esters and amides.
