- Inter-Ring Torsions in N-Phenylmaleimide and Its o-Halo Derivatives: An Experimental and Computational Study
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Structures of N-phenylmaleimide and its o-halophenyl derivatives have been determined in the solid state and show the angle between the phenyl and pyrolinyl ring planes to vary from 49.5° to 83.9° with increasing values for compounds with the larger ortho halophenyl substituents (H F ≤ Cl ≤ Br I). Experimental torsions and trends in the series are supported by semiempirical AM1 and ab initio SCF, DFT, and MP2 calculations. Calculations (AM1) on N-phenylmaleimide modeling the torsional deformation between the rings show that the barrier to planarity has a lower energy than that through a perpendicular conformation. In its o-halo derivatives, molecular planarity is not possible, and torsional deformation proceeds through the perpendicular conformation with diminishing, possibly vanishing, barriers with increasing halogen size. For chloro, bromo, and iodo derivatives, twisted ground-state molecular conformations reside in broad minima essentially centered around the perpendicular conformations. The unusually strong, longer wavelength electronic bands observed in the solution spectra of the series were modeled by Zindo/S CIS computations at the optimum AM1 molecular geometries. The observed lower energy (285-305 nm) band for the parent through the o-bromo derivative appears to arise from a {n(O,N); π (phenyl)} → π*(maleimide) transition. The next higher energy (250-285 nm) band appears to be essentially a phenyl π Ρ π* transition. In the o-iodo derivative, a phenyl π → * (C-I) transition appears to contribute to the longer wavelength band. Trends in the observed electronic spectra in acetonitrile within the series of compounds accord roughly with the results of the computations.
- Miller, Christopher W.,Hoyle, Charles E.,Valente, Edward J.,Magers, David H.,Joensson, E. Sonny
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- The discovery, design and synthesis of potent agonists of adenylyl cyclase type 2 by virtual screening combining biological evaluation
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Adenylate cyclases (ACs), play a critical role in the conversion of adenosine triphosphate (ATP) into the second messenger cyclic adenosine monophosphate (cAMP). Studies have indicated that adenylyl cyclase type 2 (AC2) is potential drug target for many diseases, however, up to now, there is no AC2-selective agonist reported. In this research, docking-based virtual screening with the combination of cell-based biological assays have been performed for discovering novel potent and selective AC2 agonists. Virtual screening disclosed a novel hit compound 8 as an AC2 agonist with EC50 value of 8.10 μM on recombinant human hAC2 + HEK293 cells. The SAR (structure activity relationship) based on the derivatives of compound 8 was further explored on recombinant AC2 cells and compound 73 was found to be the most active agonist with the EC50 of 90 nM, which is 160-fold more potent than the reported agonist Forskolin and could selectively activate AC2 to inhibit the expression of Interleukin-6. The discovery of a new class of AC2-selective agonists would provide a novel chemical probe to study the physiological function of AC2.
- Li, Shanshan,Song, Gao,Wang, Liang-Liang,Weng, Zhiying,Xu, Guowei,Yang, Weimin,Yang, Yanming,Yang, Yaqing,Zhang, Jiajun,Zuo, Zhili
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- Catalyst and Additive-Free Diastereoselective 1,3-Dipolar Cycloaddition of Quinolinium Imides with Olefins, Maleimides, and Benzynes: Direct Access to Fused N,N′-Heterocycles with Promising Activity against a Drug-Resistant Malaria Parasite
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A convenient and eco-friendly synthesis of various fused N-heterocyclic compounds through catalyst and additive-free 1,3 dipolar cycloadditions of quinolinium imides with olefins, maleimides, and benzynes in excellent yields and diastereoselectivities is reported. The thermally controlled diastereoselective [3 + 2] cycloaddition reaction between quinolinium imides and olefins provided cis-isomers at low temperature and trans-isomers at high temperature. A reaction between quinolinium imides with substituted maleimides gave four-ring-fused N-heterocyclic compounds in high yields as a single diastereomer. The aryne precursors also provided four-ring-fused N,N′-heterocyclic compounds in high yields. The in vitro antiplasmodial activity of selected molecules revealed that this class of molecules possesses potential for ongoing studies against malaria.
- Kumar, Rakesh,Chaudhary, Sandeep,Kumar, Rohit,Upadhyay, Pooja,Sahal, Dinkar,Sharma, Upendra
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p. 11552 - 11570
(2018/09/25)
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- Direct Experimental Evidence for Halogen–Aryl π Interactions in Solution from Molecular Torsion Balances
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We dissected halogen–aryl π interactions experimentally using a bicyclic N-arylimide based molecular torsion balances system, which is based on the influence of the non-bonded interaction on the equilibria between folded and unfolded states. Through comparison of balances modulated by higher halogens with fluorine balances, we determined the magnitude of the halogen–aryl π interactions in our unimolecular systems to be larger than ?5.0 kJ mol?1, which is comparable with the magnitude estimated in the biomolecular systems. Our study provides direct experimental evidence of halogen–aryl π interactions in solution, which until now have only been revealed in the solid state and evaluated theoretically by quantum-mechanical calculations.
- Sun, Han,Horatscheck, André,Martos, Vera,Bartetzko, Max,Uhrig, Ulrike,Lentz, Dieter,Schmieder, Peter,Nazaré, Marc
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supporting information
p. 6454 - 6458
(2017/05/29)
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- Potent Nematicidal Activity of Maleimide Derivatives on Meloidogyne incognita
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Different maleimide derivatives were synthesized and assayed for their in vitro activity on the soil inhabiting, plant-parasitic nematode Meloidogyne incognita, also known as root-knot nematode. The compounds maleimide, N-ethylmaleimide, N-isopropylmaleimide, and N-isobutylmaleimide showed the strongest nematicidal activity on the second stage juveniles of the root-knot nematode with EC50/72h values of 2.6 ± 1.3, 5.1 ± 3.4, 16.2 ± 5.4, and 19.0 ± 9.0 mg/L, respectively. We also determined the nematicidal activity of copper sulfate, finding an EC50 value of 48.6 ± 29.8 mg/L. When maleimide at 1 mg/L was tested in combination with copper sulfate at 50 mg/L, we observed 100% mortality of the nematodes. We performed a GC-MS metabolomics analysis after treating nematodes with maleimide at 8 mg/L for 24 h. This analysis revealed altered fatty acids and diglyceride metabolites such as oleic acid, palmitic acid, and 1-monopalmitin. Our results suggest that maleimide may be used as a new interesting building block for developing new nematicides in combination with copper salts.
- Eloh, Kodjo,Demurtas, Monica,Mura, Manuel Giacomo,Deplano, Alessandro,Onnis, Valentina,Sasanelli, Nicola,Maxia, Andrea,Caboni, Pierluigi
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p. 4876 - 4881
(2016/07/06)
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- Synthesis and biological evaluation of novel N-aryl maleimide derivatives clubbed with α-hydroxyphosphonates
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A series of novel molecules 5a-g containing N-aryl maleimide and α-hydroxyphosphonate moieties were synthesized. A distinct approach for high-yielding synthesis of α-hydroxyphosphonates has been discovered using various catalyst and solvents. The structures of the synthesized compounds were elucidated by IR, NMR, MS and CHN analysis. All the synthesized compounds were tested for qualitative (Zone of inhibition) and quantitative (MIC) antimicrobial activities against two pathogenic bacteria such as Bacillus subtilis (NCIM 2250) and Escherichia coli (ATCC 25922) and four pathogenic fungi such as Candida albicans (MTCC 277), Candida tropicalis (MTCC184), Aspergillus niger (MCIM 545) and Aspergillus clavatus (MTCC 132). The investigation of antimicrobial screening data revealed that most of the tested compounds are moderate to good microbial inhibitors.
- Patil, Nilesh S.,Deshmukh, Ganesh B.,Patil, Sambhaji V.,Bholay, Avinash D.,Gaikwad, Nitin D.
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p. 490 - 497
(2014/07/21)
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- Discovery and structural optimization of pyrazole derivatives as novel inhibitors of Cdc25B
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Structural optimization and preliminary structure-activity relationship studies of a series of N-substituted maleimide fused-pyrazole analogues with Cdc25B inhibitory activity, starting from a high-throughput screening hit, are illustrated. A simplified 3,5-diacyl pyrazole analogue was obtained as the most potent compound (118, IC50 = 0.12 μM) with a 270-fold increase in potency.
- Chen, Hai-Jun,Liu, Yong,Wang, Li-Na,Shen, Qiang,Li, Jia,Nan, Fa-Jun
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scheme or table
p. 2876 - 2879
(2010/07/04)
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- Synthesis and in vitro evaluation of N-substituted maleimide derivatives as selective monoglyceride lipase inhibitors
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The endocannabinoid 2-arachidonoylglycerol (2-AG) plays a major role in many physiological processes, and its action is quickly terminated via enzymatic hydrolysis catalyzed by monoglyceride lipase (MGL). Regulating its endogenous level could offer therapeutic opportunities; however, few selective MGL inhibitors have been described so far. Here, we describe the synthesis of N-substituted maleimides and their pharmacological evaluation on the recombinant human fatty acid amide hydrolase (FAAH) and on the purified human MGL. A few N-arylmaleimides were previously described (Saario, S. M.; Salo, O. M.; Nevalainen, T.; Poso, A.; Laitinen, J. T.; Jarvinen, T.; Niemi, R. Characterization of the Sulfhydryl-Sensitive Site in the Enzyme Responsible for Hydrolysis of 2-Arachidonoylglycerol in Rat Cerebellar Membranes. Chem. Biol. 2005, 12, 649-656) as MGL inhibitors, and along these lines, we present a new set of maleimide derivatives that showed low micromolar IC50 and high selectivity toward MGL vs FAAH. Then, structure-activity relationships have been investigated and, for instance, 1-biphenyl-4-ylmethylmaleimide inhibits MGL with an IC50 value of 790 nM. Furthermore, rapid dilution experiments reveal that these compounds act as irreversible inhibitors. In conclusion, N-substituted maleimides constitute a promising class of potent and selective MGL inhibitors.
- Matuszak, Nicolas,Muccioli, Giulio G.,Labar, Geoffray,Lambert, Didier M.
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experimental part
p. 7410 - 7420
(2010/04/30)
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- Design and synthesis of a novel DNA-encoded chemical library using Diels-Alder cycloadditions
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DNA-encoded chemical libraries are increasingly being employed for the identification of binding molecules to protein targets of pharmaceutical relevance. Here, we describe the synthesis and characterization of a DNA-encoded chemical library, consisting of 4000 compounds generated by Diels-Alder cycloaddition reactions. The compounds were encoded with unique DNA fragments which were generated through a stepwise assembly process and serve as amplifiable bar codes for the identification and relative quantification of library members.
- Buller, Fabian,Mannocci, Luca,Zhang, Yixin,Dumelin, Christoph E.,Scheuermann, Joerg,Neri, Dario
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supporting information; experimental part
p. 5926 - 5931
(2009/05/31)
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- Evaluation of N-aromatic maleimides as free radical photoinitiators: A photophysical and photopolymerization characterization
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Photopolymerizable compositions were prepared using acrylate monomers in combination with various N-aromatic maleimides. N-aromatic maleimides were segregated into two groups: those that could adopt a planar conformation and those that could not adopt a planar conformation. The maleimides were characterized using single-crystal X-ray diffraction spectroscopy, laser flash photolysis spectroscopy, UV-vis absorption spectroscopy, and photodifferential scanning calorimetry. Planar N-aromatic maleimides were found to have a low relative excited-state triplet yield, showing significant shift of the primary maleimide UV absorption band with changes in solvent polarity, and did not initiate free radial polymerization upon direct UV excitation. Twisted N-aromatic maleimides have a higher relative triplet yield, show negligible shift of the primary maleimide UV absorption band, with solvent polarity, and initiate free radical polymerization upon direct excitation. Addition of benzophenone was found to dramatically increase the initiation efficiency of both planar and twisted N-aromatic maleimides to levels approaching that of conventional cleavage photoinitiators.
- Miller, Chris W.,Sonny J?nsson,Hoyle, Charles E.,Viswanathan, Kalyanaraman,Valente, Edward J.
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p. 2707 - 2717
(2007/10/03)
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- Synthesis of Oxindole Derivatives from N-Alkenyl-o-Chloroanilides with Zero-Valent Nickel Complex
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Oxindole derivatives have been obtained from N-alkenyl-o-chloroanilides by reaction with tetrakis(triphenylphoaphine)nickel(0) in toluene as solvent in good yields.A detailed analysis of all the products of the reaction allows to confirm the postulated mechanism of the cyclization reaction.The o-chloroanilides of the 3-cyclohexenylacetic acid fails in the cyclization reaction, since the torsional hindrance seems to avoid that the endocyclic double bond may be orthogonally to the ortho-?-nickel complex intermediate on the aromatic ring.
- Canoira, L.,Rodriguez, J. G.
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p. 1511 - 1518
(2007/10/02)
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