- Enzyme-Inspired Lysine-Modified Carbon Quantum Dots Performing Carbonylation Using Urea and a Cascade Reaction for Synthesizing 2-Benzoxazolinone
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Catalysts as the dynamo of chemical reactions along with solvents play paramount roles in organic transformations in long-lasting modes. Thus, developing effective and biobased catalysts in nontoxic solvents is highly in demand. In this report, carbon quantum dots (CQDs) functionalized with-lysine (Lys-CQDs) were generated from entirely nature-derived materials; they were demonstrated to be a promising catalyst for C-N bond formation in choline chloride urea (ChCl/U), a natural deep eutectic solvent (NADES). Among a number of synthesized CQDs, Lys-CQD turned out to be a powerful catalyst in the model reaction with aniline to afford phenyl urea. This type of transformation is important because aniline as a nucleophile has low activity, and urea is a very weak electrophile but an abundant natural source of the carbonyl moiety at the same time. The optimized reaction was performed under a highly desirable condition without using tedious and toxic workup processes at a low temperature (37 °C for aliphatic amines and 60 °C for aniline derivatives), as well as by embracing the broad scope of products in good to high yields even with weak nucleophiles such as aniline. A proposed acid-activated mechanism was suggested for the model reaction that was further confirmed by detecting ammonia as the leaving group. To show further multifunctionality of the catalyst, a cascade catalysis approach was developed for synthesizing 2-benzoxazolinone, which was furnished in a two-step transformation, starting from 2-aminophenol. Using X-ray crystallography, the structure of the final product in the cascade reaction was also determined. The catalyst was characterized using various analytical techniques including SEM, TEM, AFM, XRD, IR spectroscopy, UV-vis spectroscopy, DLS, and fluorescence spectroscopy. Measuring the acid/base sites by back titration, the catalyst was shown to be highly functionalized by the lysine functional group. The size of the catalyst was determined to be in the range of 1-8 nm, having a well-dispersed surface. In all, Lys-modified CQD, as a metal-free catalyst, was synthesized, characterized, and optimized for carbonylation, as well as a cascade reaction, under mild conditions. The whole process including catalyst synthesis and organic transformations is economically competitive and fulfills all requirements toward viability.
- Hasani, Morteza,Kalhor, Hamid R.
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p. 10778 - 10788
(2021/09/08)
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- Dual palladium-photoredox catalyzed chemoselective C-H arylation of phenylureas
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A highly chemoselective C-H arylation of phenylureas has been accomplished using dual palladium-photoredox catalysis at room temperature without any additives, base or external oxidants. Regioselective C-H arylation ofN,N'-diaryl substituted unsymmetrical phenylureas has also been accomplished by a careful choice of aryl groups.
- Babu, Sakamuri Sarath,Shahid,Gopinath, Purushothaman
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supporting information
p. 5985 - 5988
(2020/06/04)
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- Catalytic hydration of cyanamides with phosphinous acid-based ruthenium(ii) and osmium(ii) complexes: scope and mechanistic insights
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The synthesis of a large variety of ureas R1R2NC(O)NH2 (R1 and R2 = alkyl, aryl or H; 26 examples) was successfully accomplished by hydration of the corresponding cyanamides R1R2NCN using the phosphinous acid-based complexes [MCl2(η6-p-cymene)(PMe2OH)] (M = Ru (1), Os (2)) as catalysts. The reactions proceeded cleanly under mild conditions (40-70 °C), in the absence of any additive, employing low metal loadings (1 molpercent) and water as the sole solvent. In almost all the cases, the osmium complex 2 featured a superior reactivity in comparison to that of its ruthenium counterpart 1. In addition, for both catalysts, the reaction rates observed for the hydration of the cyanamide substrates were remarkably faster than those involving classical aliphatic and aromatic nitriles. Computational studies allowed us to rationalize all these trends. Thus, the calculations indicated that the presence of a nitrogen atom directly linked to the CN bond depopulates electronically the nitrile carbon by inductive effect when coordinated to the metal center, thus favouring the intramolecular nucleophilic attack of the OH group of the phosphinous acid ligand to this carbon. On the other hand, the higher reactivity of Os vs. Ru seems to be related with the lower ring strain on the incipient metallacycle that starts to form in the transition state associated with this key step in the catalytic cycle. Indirect experimental evidence of the generation of the metallacyclic intermediates was obtained by studying the reactivity of [RuCl2(η6-p-cymene)(PMe2OH)] (1) towards dimethylcyanamide in methanol and ethanol. The reactions afforded compounds [RuCl(η6-p-cymene)(PMe2OR)(NCNMe2)][SbF6] (R = Me (5a), Et (5b)), resulting from the alcoholysis of the metallacycle, which could be characterized by single-crystal X-ray diffraction. This journal is
- álvarez, Daniel,Cadierno, Victorio,Crochet, Pascale,González-Fernández, Rebeca,López, Ramón,Menéndez, M. Isabel
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p. 4084 - 4098
(2020/07/09)
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- Optimization of 5-arylidene barbiturates as potent, selective, reversible LSD1 inhibitors for the treatment of acute promyelocytic leukemia
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Histone lysine specific demethylase 1 (LSD1) is overexpressed in diverse hematologic disorders and recognized as a promising target for blood medicines. In this study, molecular docking-based virtual screening united with bioevaluation was utilized to identify novel skeleton of 5-arylidene barbiturate as small-molecule inhibitors of LSD1. Among the synthesized derivatives, 12a exhibited reversible and potent inhibition (IC50 = 0.41 μM) and high selectivity over the MAO-A and MAO-B. Notably, 12a strongly induced differentiation effect on acute promyelocytic leukemia NB4 cell line and distinctly escalated the methylation level on histone 3 lysine 4 (H3K4). Our findings indicate that 5-arylidene barbiturate may represent a new skeleton of LSD1 inhibitors and 12a deserve as a promising agent for the further research.
- Xu, Siyuan,Zhou, Chen,Liu, Rongfeng,Zhu, Qihua,Xu, Yungen,Lan, Fei,Zha, Xiaoming
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p. 4871 - 4880
(2018/09/22)
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- A green and facile approach for the synthesis of N-monosubstituted ureas in water: Pd catalyzed reaction of arylcyanamides (an unexpected behavior of electron withdrawing groups)
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The Fe3O4 magnetic nano-particles were prepared, coated with tetraethyl orthosilicate (TEOS), functionalized with 3-chloropropyltrimethoxysilane (CPTMS), further functionalized with 2,2′-(piperazine-1,4-diylbis(methylene) dianiline (PDMD) and the corresponding Pd complex synthesized as a novel nano-magnetic heterogeneous catalyst (Fe3O4@SiO2@CPTMS@PDMD@Pd) to be used for the synthesis of various N-monosubstituted ureas in water. Also, in another attempt to see the effect of HCOOH, the hydration reaction of arylcyanamide was carried out in the presence of HCOOH (water + 98% HCOOH) which had two effects: it decreased the amount of the Pd catalyst from 40 to 30 mg, and the reaction condition was changed from the reflux condition to room temperature. Interestingly, the arylcyanamides with electron withdrawing groups influence the course of the reaction and need more reaction times for completion which is an unexpected behavior, probably due to the high electron density around the central carbon atom of the nitrile group.
- Habibi, Davood,Heydari, Somayyeh,Faraji, Alireza,Keypour, Hasan,Mahmoudabadi, Masoumeh
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p. 520 - 529
(2018/06/26)
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- Selective and facile oxidative desulfurization of thioureas and thiobarbituric acids with singlet molecular oxygen generated from trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane
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An efficient and facile procedure using trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane has been developed for oxidative desulfurization of thioureas and thiobarbituric acids. The reactions proceeded smoothly very fast under mild conditions in basic media at room temperature to afford the respective ureas in excellent yields. Simple procedure and work up, mild conditions, high yields, short reaction times, use of highly potent and non-toxic oxidant are the main merits of the present method.
- Azarifar, Davood,Golbaghi, Maryam
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- One-Pot Synthesis of N-Monosubstituted Ureas from Nitriles via Tiemann Rearrangement
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Amidoximes, obtained from the reaction of nitriles with hydroxylamine, underwent Tiemann rearrangement in the presence of benzenesulfonyl chlorides (TsCl or o-NsCl) to form the N-substituted cyanamides. Subsequently, acidic hydrolysis of the cyanamides afforded the corresponding N-monosubstituted ureas. The synthesis of N-monosubstituted ureas from nitriles was accomplished by three steps in one pot, which provides a direct access to versatile N-monosubstituted urea derivatives from a wide variety of nitriles.
- Wang, Chien-Hong,Hsieh, Tsung-Han,Lin, Chia-Chi,Yeh, Wen-Hsiung,Lin, Chih-An,Chien, Tun-Cheng
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p. 1823 - 1826
(2015/08/06)
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- Hybrid Pd/Fe3O4 nanowires: Fabrication, characterization, optical properties and application as magnetically reusable catalyst for the synthesis of N-monosubstituted ureas under ligand-free conditions
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This paper reports the synthesis and use of Pd/Fe3O4 nanowires, as magnetically separable catalysts for ligand-free amidation coupling reactions of aryl halides with benzylurea under microwave irradiation. Then, the in situ hydrogenolysis of the products was performed to afford the N-monosubstituted ureas from good to excellent yields. This method has the advantages of high yields, simple methodology and easy work up. The catalyst can be recovered by using a magnet and reused several times without significant loss of its catalytic activity. The catalyst was characterized using the powder XRD, SEM, EDS and UV-vis spectroscopy. Experimental absorbance spectra was compared with results from the Gans theory.
- Nasrollahzadeh, Mahmoud,Azarian, Abbas,Ehsani, Ali,Sajadi, S.Mohammad,Babaei, Ferydon
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p. 168 - 175
(2014/05/20)
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- Green synthesis, optical properties and catalytic activity of silver nanoparticles in the synthesis of N-monosubstituted ureas in water
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We report the green synthesis of silver nanoparticles by using Euphorbia condylocarpa M. bieb root extract for the synthesis of N-monosubstituted ureas in water. UV-visible studies show the absorption band at 420 nm due to surface plasmon resonance (SPR) of the silver nanoparticles. This reveals the reduction of silver ions (Ag+) to silver (Ago) which indicates the formation of silver nanoparticles (Ag NPs). This method has the advantages of high yields, simple methodology and easy work up.
- Nasrollahzadeh, Mahmoud,Babaei, Ferydon,Mohammad Sajadi,Ehsani, Ali
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p. 423 - 429
(2014/06/23)
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- Synthesis of N-arylureas in water and their N-arylation with aryl halides using copper nanoparticles loaded on natural Natrolite zeolite under ligand-free conditions
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A new method for the synthesis of N-arylureas and their N-arylation with aryl halides has been developed using copper nanoparticles supported on natural Natrolite zeolite as a reusable heterogeneous catalyst under ligand-free conditions.
- Nasrollahzadeh, Mahmoud,Enayati, Mojtaba,Khalaj, Mehdi
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p. 26264 - 26270
(2014/07/08)
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- Synthesis and crystal structure of N-(3-benzylamino-2-cyano-3- methylthioacrylyl)-N′-(substituted phenyl)ureas
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Phenylurea groups were introduced into the frame of traditional cyanoacrylate and a series of N-(3-benzylamino-2-cyano-3-methylthioacrylyl)- N′-(substituted phenyl)ureas were synthesized. All compounds are new and their structures were confirmed by 1H NMR, 13C NMR and mass spectral analyses.
- Zhong, Shi Hua,Fan, Ming Liang,Liu, Bing Yu,Wei, Dong Mei,Liu, Jian Bing
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p. 295 - 300
(2013/07/27)
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- Nano cerium oxide as a recyclable catalyst for the synthesis of N-monosubstituted ureas with the aid of acetaldoxime as an effective water surrogate
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A new method for the synthesis of N-monosubstituted ureas has been developed by the reaction of cyanamides with acetaldoxime in the presence of nano cerium oxide as an efficient and recyclable catalyst.
- Sajadi, S. Mohammad,Maham, Mehdi
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p. 623 - 625
(2013/11/06)
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- Imidazole incorporated semicarbazone derivatives as a new class of anticonvulsants: Design, synthesis and in-vivo screening
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A series of novel imidazole incorporated semicarbazones was synthesized using an appropriate synthetic route and characterized by spectral analysis (IR, 1H NMR, 13C NMR and Mass). The anticonvulsant activity of the synthesized compounds was determined using doses of 30, 100, and 300 mg kg-1 against maximal electroshock seizure (MES), subcutaneous pentylenetetrazole (scPTZ) induced seizure and minimal neurotoxicity test. Six compounds exhibited protection in both models and 2-(1-(4-chlorophenyl)-2-(1H-imidazol-1-yl)ethylidene)-N-p- tolylsemicarbazone emerged as the most active compound of the series without any neurotoxicity and significant CNS depressant effect. Liver enzyme estimations (SGOT, SGPT, Alkaline phosphatase) of the compound also showed no significant change in the enzymes levels. Moreover, it caused 80% elevation of γ-amino butyric acid (GABA) levels in the whole mice brain, thus indicating that it could be a promising candidate in designing of a potent anticonvulsant drug.
- Amir, Mohammad,Ali, Israr,Hassan, Mohd. Zaheen
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p. 571 - 580
(2013/07/28)
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- Ionic liquid mediated one-pot synthesis of 6-aminouracils
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A novel, one-pot synthesis of 6-aminouracils via in situ generated ureas and cyanoacetylureas in the presence of an ionic liquid catalyst, 1,1,3,3-tetramethylguanidine acetate, is described. The catalyst can be recycled for five consecutive runs without loss of activity. The mechanism for the ring closure of cyanoacetylurea to 6-aminouracil is also discussed.
- Chavan, Sunil S.,Degani, Mariam S.
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supporting information; experimental part
p. 296 - 299
(2012/03/26)
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- Design, synthesis, and potential CNS activity of some new bioactive 1-(4-substituted-phenyl)-3-(4-oxo-2-methyl- 4H-quinazolin-3-yl)-urea
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Twelve new 1-(4-substituted-phenyl)-3-(4-oxo- 2-methyl-4H-quinazolin-3-yl)- urea were synthesized and screened for anticonvulsant, CNS depressant, and sedativehypnotic activity. After i.p. injection to mice at doses of 30, 100, and 300 mg/kg body weight 2,3-Disubstitutedquinazolin- 4(3H)-one were examined in the maximal electroshock-induced seizures (MES) and subcutaneous pentylenetetrazole (scPTZ) induced seizure models in mice. Spectroscopic data and elemental analysis were consistent with the newly synthesized compounds. The neurotoxicity was assessed using the rotorod method. M3, M4 and M10 were found to be active in both MES screen and scPTZ screen at 0.5 h. All except M11 showed more than 44% decrease in locomotor activity after 1 h of compound administration via actophotometer screen. CNS-depressant activity screened with the help of the forced swim method resulted into some potent compounds. Except for M6 and M11 other tested compounds were found to exhibit potent CNS depressants activity as indicated by increased immobility time. It can be concluded that newly synthesized compounds possessed sedative-hypnotic and CNS depressant activities. Springer Science+Business Media, LLC 2010.
- Kashaw, Sushil K.,Kashaw, Varsha,Mishra, Pradeep,Jain,Stables
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experimental part
p. 738 - 745
(2012/05/20)
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- Microwave-assisted synthesis of N-monosubstituted urea derivatives
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An easy and rapid procedure for the preparation of N-monosubstituted ureas via reaction between potassium cyanate and a wide range of amines is described. The procedure was performed under microwave irradiation using water as solvent. This methodology is particularly attractive since it provides ureas in high yield and purity. Georg Thieme Verlag Stuttgart · New York.
- De Luca, Lidia,Porcheddu, Andrea,Giacomelli, Giampaolo,Murgia, Irene
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scheme or table
p. 2439 - 2442
(2010/11/18)
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- Synthesis, anticonvulsant and CNS depressant activity of some new bioactive 1-(4-substituted-phenyl)-3-(4-oxo-2-phenyl/ethyl-4H-quinazolin-3-yl)-urea
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Several new 1-(4-substituted-phenyl)-3-(4-oxo-2-phenyl/ethyl-4H-quinazolin-3-yl)-urea were synthesized and screened for anticonvulsant, CNS depressant and sedative-hypnotic activity in the mice. After i.p. injection to mice at doses of 30, 100, and 300 mg/kg body weight synthesized compounds were examined in the maximal electroshock induced seizures (MES) and subcutaneous pentylenetetrazole (scPTZ) induced seizure models in mice. Spectroscopic data and elemental analysis were consistent with the newly synthesized compounds. The neurotoxicity was assessed using the rotorod method. Compounds E1, E6, E9, E12, P3, P4 and P6 were found to be active in the MES screen whereas E1, P4, P6 and P11 were found to be active in the scPTZ screen. All except E6, E11 and P6 showed more than 50% decrease in locomotor activity at 1 h of compound administration via actophotometer screen. CNS depressant activity screened with the help of the forced swim method resulted into some potent compounds. All the compounds were found to exhibit potent CNS depressants activity as indicated by increased immobility time. It can be concluded that newly synthesized compounds possessed promising CNS activities.
- Kashaw, Sushil K.,Kashaw, Varsha,Mishra, Pradeep,Jain,Stables
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experimental part
p. 4335 - 4343
(2009/12/24)
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