- Investigation of active sites using solid state 27Al and 31P MAS NMR in ceramic amorphous aluminophosphate materials prepared from different potassium salts of phosphate for the synthesis of diphenyl urea derivatives
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Ceramic amorphous aluminophosphate (CAmAlP) catalysts were prepared by precipitation method using different phosphate salts of potassium such as KH2PO4, K4P2O7 and K2HPO4 as well as H3PO4. The prepared materials were characterized by PXRD, FT-IR, XPS, SEM, BET Surface area, NH3-TPD, 27Al NMR and 31P NMR analytical methods. The catalytic activity of the materials was checked in the synthesis of diphenyl urea (DPU) from aniline and diethyl carbonate, under refluxing conditions. Further, the general application of the catalysts was tested using various substituted anilines. The recyclability of the catalysts was also studied. Uncertainties in percentage yields were calculated to check the reproducible surface properties. The P-XRD, BET Surface area and NH3-TPD results indicated that the materials were amorphous with mesoporous texture, surface areas and acidities in the range 200–260 m2/g and 0.4–0.7 mmol/g respectively. 27Al NMR studies revealed that Al is present in three different coordination states such as tetrahedral, pentagonal and octahedral. The relative percentages of these Al sites depends on the type of the potassium precursor phosphate salt used. Both tetrahedral and pentagonal Al sites in conjunction with each other represented catalytically active sites. An increase in the pentagonal sites contributed to additional increments to the catalytic activity of CAmAlP. The catalyst prepared from KH2PO4 was found to be the best and demonstrated 96% DPU yield.
- Harish,Kathyayini,Baby, Bindhu,Nagaraju
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- Antiproliferative effects of novel urea derivatives against human prostate and lung cancer cells; And their inhibition of β-glucuronidase activity
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Twenty-one novel urea derivatives were synthesized and their structures characterized by mass, NMR, IR, and UV spectroscopy. These compounds were evaluated for their antiproliferative profile against human PC-3 (prostate) and NCI-H460 (lung) cancer cell lines. Among them, compound 21 N-(3-nitrophenyl)- N′-(1-phenylethyl)urea was found to be active against both PC-3 (IC 50 ± SEM: 20.13 ± 0.91 μM) and NCI-H460 (GI 50: 22 ± 2.6 μM) cell lines; hence has the potential to be further studied as anticancer agent. These compounds were also investigated for their ability to inhibit urease, β-glucuronidase, and phosphodiesterase enzymes. N-(2,6-Dimethylphenyl)-N′-(4′-nitrophenyl)urea (1) demonstrated 90 % inhibition of β-glucuronidase enzyme (IC50 ± SEM: 3.38 ± 0.043 μM).
- Perveen, Shahnaz,Mustafa, Sana,Qamar, Kehkashan,Dar, Ahsana,Khan, Khalid M.,Choudhary, Muhammad Iqbal,Khan, Ajmal,Voelter, Wolfgang
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p. 1099 - 1113
(2014/03/21)
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- A simple and efficient synthesis of diaryl ureas with reduction of the intermediate isocyanate by triethylamine
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Thirty symmetrical diaryl urea derivatives were synthesised in moderate to excellent yields from arylamine and triphosgene with triethylamine as a reducing agent for the intermediate, isocyanate. It was significant that part of the products could be collected in almost quantitative yield without column chromatography. The procedure under mild reaction conditions was tolerant of a wide range of functional groups. The structures of the compounds were determined by NMR, MS and X-ray crystallographic analyses.
- Zhou, Shuguang,Yao, Ting,Yi, Jicheng,Li, Dashuai,Xiong, Jing
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p. 315 - 319
(2013/07/27)
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- 1,3-disubstituted ureas as antiglycating agents
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Twenty one (21) 1,3-disubstituted urea derivatives were screened for their antiglycating potential and some of them displayed promising activity. Compound N-butyl-N'-(4-nitrophenyl)urea (6) and Nisopropyl-N'-(4-nitrophenyl)urea (18) exhibited excellent activity and could be investigated in search of medicines treating diabetes and associated complications.
- Perveen, Shahnaz,Mustafa, Sana,Khan, Khalid Mohammed,Choudhary, Muhammad Iqbal
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p. 1603 - 1611
(2014/03/21)
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- Palladium-catalyzed carbonylation of amines: Switchable approaches to carbamates and N,N′-disubstituted ureas
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Switchable access to carbamates and ureas has been developed by solvent control palladium-catalyzed carbonylation of aromatic amines under an atmosphere of carbon monoxide. A variety of N-phenylcarbamates and N,N′- diphenylureas was easily synthesized in good to excellent yields from readily available aromatic amines under mild conditions. Copyright
- Guan, Zheng-Hui,Lei, Hao,Chen, Ming,Ren, Zhi-Hui,Bai, Yinjuan,Wang, Yao-Yu
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supporting information; experimental part
p. 489 - 496
(2012/04/04)
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- Discovery of the first small molecule inhibitor of human DDX3 specifically designed to target the RNA binding site: Towards the next generation HIV-1 inhibitors
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Efficacy of currently approved anti-HIV drugs is hampered by mutations of the viral enzymes, leading invariably to drug resistance and chemotherapy failure. Recent data suggest that cellular co-factors also represent useful targets for anti-HIV therapy. H
- Radi, Marco,Falchi, Federico,Garbelli, Anna,Samuele, Alberta,Bernardo, Vincenzo,Paolucci, Stefania,Baldanti, Fausto,Schenone, Silvia,Manetti, Fabrizio,Maga, Giovanni,Botta, Maurizio
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supporting information; experimental part
p. 2094 - 2098
(2012/04/17)
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- Substituted urea derivatives: A potent class of antidepressant agents
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A series of fourteen (14) N-nitrophenyl-N'-(alkyl/aryl)urea and symmetrical 1,3-disubstituted urea derivatives were synthesized and evaluated for their antidepressant activity in mice. Among them, N-(4-nitrophenyl)-N'-(1'- phenylethyl)urea (1), demonstrat
- Perveen, Shahnaz,Mustafa, Sana,Khan, Muhammad A.,Dar, Ahsana,Khan, Khalid M.,Voelter, Wolfgang
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experimental part
p. 330 - 336
(2012/08/28)
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- COMPOUNDS WITH DDX3 INHIBITORY ACTIVITY AND USES THEREOF
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The present invention relates to the medical use of the compound of formula 1,2,3 or 4
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Page/Page column 148
(2011/04/25)
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- An unplanned synthesis of symmetrical 1,3-disubstituted ureas
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When urea derivatives (N-aryl-N′, N'-dialkyl urea) or (N-aryl-N'-alkyl/arvl urea) la-lu react with diethylcarbamyl chloride at 50-60°C symmetrical 1,3-disubstituted ureas 2a-2f were furmed as major products instead of forming ployureas.
- Perveen, Shahnaz,Mustafa, Sana,Khan, Khalid Mohammed
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experimental part
p. 229 - 234
(2011/10/05)
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- Effect of successive increase in alcohol chains on reaction with isocyanates and isothiocyanates
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The reaction of isocyanates and isothiocyanates with long-chain alcohols, e.g. n-hexanol, n-heptanol and n-octanol, exclusively gave N-aryl-O-alkyl carbamates, while N-aryl-O-alkyl carbamates were formed along with symmetrical 1,3-disubstituted ureas and thioureas when the same reactions were carried out with small-chain alcohols at room temperature without using any solvent.
- Perveen, Shahnaz,Yasmin, Arfa,Khan, Khalid Mohammed
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experimental part
p. 18 - 23
(2010/04/23)
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- An 'inside-out' approach to suramin analogues
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An approach to the synthesis of suramin analogues has been realised, which avoids synthetic problems associated with conventional routes. The use of isobutyl ester protecting groups for sulfonic acids was crucial to the success of the strategy, because these were able to be cleanly deprotected with sodium iodide, yielding the sodium salts of the corresponding sulfonic acids.
- McGeary, Ross P.,Bennett, Andrew J.,Tran, Quoc B.,Prins, Johannes,Ross, Benjamin P.
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experimental part
p. 3990 - 3997
(2009/10/09)
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- Controlling molecular crystal polymorphism with self-assembled monolayer templates
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The control of crystal polymorphism is a long-standing issue in solid-state chemistry, which has many practical implications for a variety of commercial applications. At least four different crystalline forms of 1,3-bis(m- nitrophenyl) urea (MNPU), a clas
- Hiremath, Rupa,Basile, Joseph A.,Varney, Stephen W.,Swift, Jennifer A.
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p. 18321 - 18327
(2007/10/03)
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- Neat carbomethoxypivaloylketene - Preparation and chemical reactivity
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Neat carbomethoxypivaloylketene, the first fairly persistent α-oxoketene stabilized both electronically as well as sterically, is generated by flash vacuum pyrolysis of the corresponding furan-2,3-dione. It adds primary amines to afford pivaloyl-malonic acid amides and undergoes hetero-Diels-Alder reactions to furnish usual and unusual [4 + 2] adducts. Some stereo- and regiochemical features are verified with aid of 2D NMR experiments and a X-ray structure analysis.
- Stadler, Alexander,Zangger, Klaus,Belaj, Ferdinand,Kollenz, Gert
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p. 6757 - 6763
(2007/10/03)
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- A simple one-pot procedure for preparing symmetrical diaryllureas from carbon dioxide and aromatic amines
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Symmetrical diarylureas can be prepared by purging an aromatic amine with carbon dioxide in the presence of a strong amidine base followed addition of solid commercially available Me3N·SO3. Work up is simply by dilution with water. The procedure is far simpler and safer than traditional methods using phosgene or isocyanates.
- Cooper,Falcone
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p. 2467 - 2474
(2007/10/02)
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- Experimental and Theoretical Studies of Substituent Effects in Hydrogen Bond Based Molecular Recognition of a Zwitterion by Substituted Arylureas
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Electron withdrawing groups have a strong effect on hydrogen bonding to aryl ureas.The effect of para substituents modestly exceeds the effect of meta substituents.Among common substituent parameters, ?- (ρ = 1.77, r2 = 0.988) is found to be the best predictor for the observed effects of para substituents in aryl ureas.Semi-empirical and ab initio methods are used to calculate charge distributions in substituted benzene derivatives and in these ureas.A comparison of experimental and predicted (AM1, STO3G, 321-G*, 631-G**) dipole moments of benzene derivatives is presented.It is shown that calculated surface electric potentials for these thioureas succesfully predict the relative hydrogen bonded association energies.
- Wilcox, Craig S.,Kim, Eun-il,Romano, David,Kuo, Lung Huang,Burt, Arthur L.,Curran, Dennis P.
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p. 621 - 634
(2007/10/02)
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- NEW ROUTE FOR THE SYNTHESIS OF SYMMETRICAL DIARYLUREA
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Several esters of aryl carbamic acid were thermally dissociated into symmetrically diarylurea in high yields.The electronic effect and position of the substitution in the aryl groups as well as the role of the alkyl groups on the thermal reaction are discussed.
- Hassan, Alaa A.,Mourad, Aboul-Fetouh E.
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p. 397 - 404
(2007/10/02)
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- A new route for the synthesis of symmetrical diarylureas
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Several esters of arylcarbamic acid have been thermally dissociated into symmetrical diarylureas in high yields.The electronic effect and position of substitution in the aryl groups as well as the role of alkyl groups on thermal reaction have been discussed.
- Hassan, Alaa A,Mourad, Aboul-fetouh E
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p. 277 - 279
(2007/10/02)
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- Hydrogen bond directed cocrystallization and molecular recognition properties of diarylureas
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The hydrogen bond directed molecular recognition properties of a series of diarylurea (DAU) compounds have been studied using cocrystallization to probe hydrogen bond donor and acceptor selectivity of the host and guest molecules. Diarylureas with meta-substituted electron-withdrawing groups on the aryl rings are capable of forming cocrystal complexes with a wide variety of hydrogen bond acceptors. One particular DAU, 1,3-bis(m-nitrophenyl)urea, behaves primarily as a proton donor, one of the few organic molecules known to have this property. Its hydrogen bond accepting ability is drastically reduced, possibly because of two very weak CH?O interactions occurring in response to the presence of guest acceptor molecules and effectively negating the powerful proton-accepting ability of the urea carbonyl group. Only DAU compounds with meta-substituted electron-withdrawing groups have this property. The crystal structures of four DAU compounds and six of their cocrystal structures are reported. In addition, 19 other DAU cocrystals were prepared and characterized by chemical and spectroscopic means, and their hydrogen bond patterns were assigned based on spectroscopic analogies to those with known crystal structures. From this data hydrogen bond rules for diarylureas have been derived for use in predicting hydrogen bond patterns in related structures.
- Etter, Margaret C.,Urba?czyk-Lipkowska, Zofia,Zia-Ebrahimi, Mohammad,Panunto, Thomas W.
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p. 8415 - 8426
(2007/10/02)
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- Nucleophilic Substitutions at Carbonic Acid Derivatives. XX. Aminolysis of Bis(trichlormethyl)carbonate
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The rate constants for the two steps of the reaction of bis(trichlormethyl)carbonate with substituted anilines have been determinated by conductivity measurements.The first relatively fast step of the reaction is the nucleophilic attack of the amine to the bis(trichloromethyl)carbonate leading to trichloromethylurethane through a six or four centers transition state in wich the carbon-nitrogen bond is formed parallel with the transfer of the proton.In this reaction a phosgene molecule is also produced, which reacts very fast with amine to form a N,N'-diarylurea.The s econd, much slower step, is the nucleophilic attack of the amine to the trichloromethylurethane.Through a similar transition state in which the proton transfer has even a higher importance, a N,N'-disubstituted urea and an other molecule of phosgene are formed.
- Cotarca, Livius,Bacaloglu, R.,Csunderlik, C.,Marcu, N.,Tarnaveanu, A.
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p. 1052 - 1062
(2007/10/02)
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- Novel Bis as Antitrypanosomal Agents
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A series of novel 1,1'-(4,1-phenylene)bis was prepared and evaluated for activity against Trypanosoma rhodesiense in mice.The importance of the bis structure and the nature of the spacer between the two phenyl rings for optimal activity have been revealed.The potent parenteral activity of several analogues within this series as well as preliminary indication of oral activity lends encouragement to further development of this structural class.
- Turner, William R.,Werbel, Leslie M.
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p. 1728 - 1740
(2007/10/02)
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- SUBSTITUENT EFFECTS ON HYDROLYTIC STABILITY AND HERBICIDAL ACTIVITY OF 3-ARYLIMIDAZOLIDINE-2,4-DIONES
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Twenty-one derivatives of imidazolidine-2,4-dione have been prepared by reactions of substituted amino acids with aryl isocyanates in aqueous medium.Pre- and post-emergent herbicidal activities of all the compounds have been tested, and stability of five derivatives has been followed in aqueous medium within the pH range from 7.6 to 13.0.The highest pre-emergent herbicidal activity has been found with the derivatives XI-XVI which inhibit the growth of most indicator plants at the doses of 1.6 kg/ha.The derivatives studied are relatively stable in aqueous medium, the hydrolysis half-life of the compound XI being 9 days at pH 8.
- Cegan, Alexandr,Vecera, Miroslav
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p. 1521 - 1528
(2007/10/02)
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