- Tropylium-promoted Ritter reactions
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The Ritter reaction used to be one of the most powerful synthetic tools to functionalize alcohols and nitriles, providing valuableN-alkyl amide products. However, this reaction has not been frequently used in modern organic synthesis due to its employment of strongly acidic and harsh reaction conditions, which often lead to complicated side reactions. Herein, we report the development of a new method using salts of the tropylium ion to promote the Ritter reaction. This method works well on a range of alcohol and nitrile substrates, giving the corresponding products in good to excellent yields. This reaction protocol is amenable to microwave and continuous flow reactors, offering an attractive opportunity for further applications in organic synthesis.
- Doan, Son H.,Hussein, Mohanad A.,Nguyen, Thanh Vinh
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supporting information
p. 8901 - 8904
(2021/09/10)
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- Non-alkylator anti-glioblastoma agents induced cell cycle G2/M arrest and apoptosis: Design, in silico physicochemical and SAR studies of 2-aminoquinoline-3-carboxamides
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Malignant gliomas are the most common brain tumors, with generally dismal prognosis, early clinical deterioration and high mortality. Recently, 2-aminoquinoline scaffold derivatives have shown pronounced activity in central nervous system disorders. We herein reported a series of 2-aminoquinoline-3-carboxamides as novel non-alkylator anti-glioblastoma agents. The synthesized compounds showed comparable activity to cisplatin against glioblastoma cell line U87 MG in vitro. Among them, we found that 6a displayed good inhibitory activity against A172 and U118 MG glioblastoma cell lines and induced cell cycle arrest in the G2/M phase and apoptosis in U87 MG by flow cytometry analysis. Additionally, 6a displayed low cytotoxicity to several normal human cell lines. In silico study showed 6a had promising physicochemical properties and was predicted to cross the blood–brain barrier. Moreover, preliminary structure–activity relationships are also investigated, shedding light on further modifications towards more potent agents on this series of compounds. Our results suggest this compound has a promising potential as an anti-glioblastoma agent with a differential effect between tumor and non-malignant cells.
- Gu, Xiangyu,Liu, Jianwen,Ni, Xintong,Qi, Yingxue,Qian, Xuhong,Shao, Xusheng,Xu, Xiaoyong,Yuan, Pengtao
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supporting information
(2021/09/22)
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- X-ray Structure and Molecular Docking Guided Discovery of Novel Chitinase Inhibitors with a Scaffold of Dipyridopyrimidine-3-carboxamide
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Chitinases are the glycosyl hydrolase for catalyzing the degradation of chitin and play an indispensable role in bacterial pathogenesis, fungal cell wall remodeling, and insect molting. Thus, chitinases are attractive targets for therapeutic drugs and pes
- Yuan, Pengtao,Jiang, Xi,Wang, Siyu,Shao, Xusheng,Yang, Qing,Qian, Xuhong
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p. 13584 - 13593
(2020/12/02)
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- Synthesis and biological evaluation of flavone-8-acrylamide derivatives as potential multi-target-directed anti Alzheimer agents and investigation of binding mechanism with acetylcholinesterase
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In a search for novel multifunctional anti-Alzheimer agents, a congeneric set of seventeen flavone-8-acrylamide derivatives (8a─q)were synthesized and evaluated for their cholinesterase inhibitory, antioxidant, neuroprotective and modulation of Aβ aggregation activities. The target compounds showed effective and selective inhibitory activity against the AChE over BuChE. In addition, the target compounds also showed moderate anti-oxidant activity and strong neuroprotective capacities, and accelerated dosage-dependently the Aβ aggregation. Also, we presented here a complete study on the interaction of 8a, 8d, 8e, 8h and 8i with AChE. Through fluorescence emission studies, the binding sites number found to be 1, binding constants were calculated as 2.04 × 104, 2.22 × 104, 1.18 × 104, 9.8 × 103 and 3.2 × 104 M?1 and free energy change as ?5.83, ?5.91, ?5.51, ?5.41 and ?6.12 kcal M?1 at 25 °C which were well agreed with the computational calculations indicating a strong binding affinity of flavones and AChE. Furthermore, the CD studies revealed that the secondary structure of AChE became partly unfolded upon binding with 8a, 8d, 8e, 8h and 8i.
- Shaik, Jeelan Basha,Yeggoni, Daniel Pushparaju,Kandrakonda, Yelamanda Rao,Penumala, Mohan,Zinka, Raveendra Babu,Kotapati, Kasi Viswanath,Darla, Mark Manidhar,Ampasala, Dinakara Rao,Subramanyam, Rajagopal,Amooru, Damu Gangaiah
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- New Flavone-Cyanoacetamide Hybrids with a Combination of Cholinergic, Antioxidant, Modulation of β-Amyloid Aggregation, and Neuroprotection Properties as Innovative Multifunctional Therapeutic Candidates for Alzheimer's Disease and Unraveling Their Mechanism of Action with Acetylcholinesterase
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In line with the modern multi-target-directed ligand paradigm of Alzheimer's disease (AD), a series of 19 compounds composed of flavone and cyanoacetamide groups have been synthesized and evaluated as multifunctional agents against AD. Biological evaluation demonstrated that compounds 7j, 7n, 7o, 7r, and 7s exhibited excellent inhibitory potency (AChE, IC50 of 0.271 ± 0.012 to 1.006 ± 0.075 μM) and good selectivity toward acetylcholinesterase, significant antioxidant activity, good modulation effects on self-induced Aβ aggregation, low cytotoxicity, and neuroprotection in human neuroblastoma SK-N-SH cells. Further, an inclusive study on the interaction of 7j, 7n, 7o, 7r, and 7s with AChE at physiological pH 7.2 using fluorescence, circular dichroism, and molecular docking methods suggested that these derivatives bind strongly to the peripheral anionic site of AChE mostly through hydrophobic interactions. Overall, the multifunctional profiles and strong AChE binding affinity highlight these compounds as promising prototypes for further pursuit of innovative multifunctional drugs for AD.
- Basha, Shaik Jeelan,Mohan, Penumala,Yeggoni, Daniel Pushparaju,Babu, Zinka Raveendra,Kumar, Palaka Bhagath,Rao, Ampasala Dinakara,Subramanyam, Rajagopal,Damu, Amooru Gangaiah
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p. 2206 - 2223
(2018/05/23)
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- Synthesis, pharmacological assessment, molecular modeling and in silico studies of fused tricyclic coumarin derivatives as a new family of multifunctional anti-Alzheimer agents
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A series of fused tricyclic coumarin derivatives bearing iminopyran ring connected to various amido moieties were developed as potential multifunctional anti-Alzheimer agents for their cholinesterase inhibitory and radical scavenging activities. In vitro studies revealed that most of these compounds exhibited high inhibitory activity on acetylcholinesterase (AChE), with IC50 values ranging from 0.003 to 0.357 μM which is 2-220 folds more potent than the positive control, galantamine. Their inhibition selectivity against AChE over butyrylcholinesterase (BuChE) has increased about 194 fold compared with galantamine. The developed compounds also showed potent ABTS radical scavenging activity (IC50 7.98-15.99 μM). Specifically, the most potent AChE inhibitor 6n (IC50 0.003 ± 0.0007 μM) has an excellent antioxidant profile as determined by the ABTS method (IC50 7.98 ± 0.77 μM). Moreover, cell viability studies in SK N SH cells showed that the compounds 6m-q have significant neuroprotective effects against H2O2-induced cell death, and are not neurotoxic at all concentrations except 6n and 6q. The kinetic analysis of compound 6n proved that it is a mixed-type inhibitor for EeAChE (Ki1 0.0103 μM and Ki2 0.0193 μM). Accordingly, the molecular modeling study demonstrated that 6m-q with substituted benzyl amido moiety possessed an optimal docking pose with interactions at catalytic active site (CAS) and peripheral anionic site (PAS) of AChE simultaneously and thereby they might prevent aggregation of Aβ induced by AChE. Furthermore, in silico ADMET prediction studies indicated that these compounds satisfied all the characteristics of CNS acting drugs. Most active inhibitor 6n is permeable to BBB as determined in the in vivo brain AChE activity. To sum up, the multipotent therapuetic profile of these novel tricyclic coumarins makes them promising leads for developing anti-Alzheimer agents.
- Shaik, Jeelan Basha,Palaka, Bhagath Kumar,Penumala, Mohan,Kotapati, Kasi Viswanath,Devineni, Subba Rao,Eadlapalli, Siddhartha,Darla, M. Manidhar,Ampasala, Dinakara Rao,Vadde, Ramakrishna,Amooru, G. Damu
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p. 219 - 232
(2015/11/24)
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- Synthesis, Biological Evaluation, and Molecular Docking of 8-imino-2-oxo-2H,8H-pyrano[2,3-f]chromene Analogs: New Dual AChE Inhibitors as Potential Drugs for the Treatment of Alzheimer's Disease
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Alzheimer's disease onset and progression are associated with the dysregulation of multiple and complex physiological processes, and a successful therapeutic approach should therefore address more than one target. In line with this modern paradigm, a series of 8-imino-2-oxo-2H,8H-pyrano[2,3-f]chromene analogs (4a–q) were synthesized and evaluated for their multitarget-directed activity on acetylcholinesterase, butyrylcholinesterase (BuChE), 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical, and amyloid-β peptide (Aβ) specific targets for Alzheimer's disease therapy. Most of the synthesized compounds showed remarkable acetylcholinesterase inhibitory activities in low nm concentrations and good ABTS radical scavenging activity, however, no evidence of BuChE inhibitory activity. Among them, 3-bromobenzylamide derivative 4m exhibited the best acetylcholinesterase inhibitory activity with IC50 value of 13 ± 1.4 nm which is 51-fold superior to galantamine, a reference drug. Kinetic and molecular docking studies indicated 4m as mixed-type inhibitor, binding simultaneously to catalytic active and peripheral anionic sites of acetylcholinesterase. Five compounds 4e, 4f, 4g, 4j, and 4k have shown 1.4- to 2.5-fold of higher antioxidant activities than trolox. Interestingly, the most active compound 4m demonstrated dosage-dependent acceleration of Aβ1?42 aggregation, which may reduce toxicity of oligomers. Overall, these results lead to discovery of fused tricyclic coumarins as promising dual binding site inhibitors of acetylcholinesterase and afford multifunctional compounds with potential impact for further pharmacological development in Alzheimer's therapy.
- Shaik, Jeelan Basha,Palaka, Bhagath Kumar,Penumala, Mohan,Eadlapalli, Siddhartha,Darla Mark, Manidhar,Ampasala, Dinakara Rao,Vadde, Ramakrishna,Amooru Gangaiah, Damu
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- Chemoenzymatic route to Tyrphostins involving lipase-catalyzed kinetic resolution of 1-phenylethanamine with alkyl cyanoacetates as novel acylating agents
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Ethyl and isopropyl cyanoacetates were tested as acylating agents in the kinetic resolution of racemic 1-phenylethanamine rac-1 catalyzed by lipase B from Candida antarctica. The best conversion combined with high enantioselectivity was achieved with ethyl cyanoacetate 2a as the acylating agent and immobilized lipase B from Candida antarctica (CaLB N435) as the biocatalyst. Enantiomers of the amides (R)-3 and (S)-3 were obtained with high enantiopurity (ee >98%) by lipase-catalyzed kinetic resolution and by chemical conversion of the residual (S)-1, respectively. The amides were reacted with various aromatic aldehydes 4a-c,e in Knoevenagel condensation to yield Tyrphostins rac-5a-c,e, (R)-5a-c,e and (S)-5a-c,e, which were tested as protein tyrosine kinase inhibitors on human cancer cell lines HCT 116, A549, PC9, PC9ER, Jurkat, and MV4-11. Although some of the novel Tyrphostins exhibited weak biological activities (EC50 ~6-60 μM), none of them proved to have a significant effect on the growth of the investigated cell lines.
- Csuka, Pál,Boros, Zoltán,Orfi, László,Dobos, Judit,Poppe, László,Hornyánszky, Gábor
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p. 644 - 649
(2015/08/03)
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- Synthesis of new 8-formyl-4-methyl-7-hydroxy coumarin derivatives
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8-Formyl-4-Methyl-7-Hydroxy Coumarin Derivatives were synthesized via Penchem condensation followed by Duffs reaction. Treatment of this with N,N-di substituted cyano acetamides in the presence of piperdine afforded New 8- Formyl-4-Methyl-7-Hydroxy Coumarin Derivatives (7a-o). Their structures were characterized by IR, 1H and 13C NMR and Mass spectral and elemental analysis data.
- Manidhar,Rao, K. Uma Maheswara,Reddy, N. Bakthavatchala,Sundar, Ch. Syama,Reddy, C. Suresh
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p. 459 - 463
(2012/11/07)
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- Synthesis and insecticidal activities of novel neonicotinoid analogs bearing an amide moiety
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Figure represented. A series of novel neonicotinoid analogs containing an amide moiety were synthesized, characterized, and subsequently evaluated for their insecticidal activity. According to the preliminary bioassay, the compounds 6c, 6e, 6f, 6j, 6n, and 6r exhibited > 50% activity against Nilaparvata lugens at 100 mg/L. Amongst the active compounds, 6f and 6r revealed insecticidal activities similar to that displayed by standard buprofezin. J. Heterocyclic Chem., (2011)
- Wu, Jian,Yang, Song,Song, Bao-An,Bhadury, Pinaki S.,Hu, De-Yu,Zeng, Song,Xie, Hua-Peng
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scheme or table
p. 901 - 906
(2011/10/02)
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- Modulators of LXR
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Compounds, compositions and methods for modulating the activity of nuclear receptors are provided. In particular, heterocyclic compounds are provided for modulating the activity of nuclear receptors, including liver X receptor (LXR) and orphan nuclear receptors. In certain embodiments, the compounds are N-substituted pyridones.
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- Tyrphostins. 2. Heterocyclic and α-Substituted Benzylidenemalonitrile Tyrphostins as Potent Inhibitors of EGF Receptor and ErbB2/neu Tyrosine Kinases
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We have previously described a novel series of low molecular weight protein tyrosine kinase inhibitors which we named tyrphostins.The characteristic active pharmacophore of these compounds was the hydroxy-cis-benzylidenemalonitrile moiety.In this article we describe three novel groups of tyrphostins: (i) one group has the phenolic moiety of the cis-benzylidenemalononitrile replaced either with other substituted benzenes or with heteroaromatic rings, (ii) another is a series of conformationally constrained derivatives of hydroxy-cis-benzylidenemalononitriles in which the malononitrile moiety is fixed relative to the aromatic ring, and (iii) two groups of compounds in which the position trans to the benzenemalononitrile has been substituted by ketones and amides.Among the novel tyrphostins examined we found inhibitors which discriminate between the highly homologous EGF receptor kinase (HER1) and ErbB2/neu kinase (HER2).These findings may lead to selective tyrosine kinase blockers for the treatment of diseases in which ErbB2/neu is involved.
- Gazit, Aviv,Osherov, Nir,Posner, Israel,Yaish, Pnina,Poradosu, Enrique,et al.
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p. 1896 - 1907
(2007/10/02)
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