- Asymmetric synthesis of piperidines using the nitro-Mannich reaction☆
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A method for the synthesis of functionalized piperidines containing 3 contiguous stereocentres in the 2-,3- and 4- positions uses a diastereoselective nitro-Mannich to control stereochemistry. The nitro-Mannich reaction between a β-aryl/heteroaryl substituted nitroalkanes and glyoxylate imine provides β-nitro-amines with good selectivity (70:30 to >95:5) for the syn, anti-diastereoisomers. Reductive cyclisation with BF3.OEt2 and Et3SiH gave, after purification, stereochemically pure piperidines in 19–57% yield for ten examples with different 4-aryl/heteroaryl substituents.
- Anderson, James C.,Bouvier-Israel, Eva,Rundell, Christopher D.,Zhang, Xiangyu
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- Intramolecular Sakurai Allylation of Geminal Bis(silyl) Enamide with Indolenine. A Diastereoselective Cyclization to Form Functionalized Hexahydropyrido[3,4- b]Indole
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A fluoride-promoted intramolecular Sakurai allylation of geminal bis(silyl) enamide with indolenine has been developed. The reaction facilitates an efficient cyclization to give hexahydropyrido[3,4-b]indoles in good yields with high diastereoselectivity. The resulted cis, trans-stereochemistry further enables the ring-closing metathesis (RCM) reaction of two alkene moieties, giving a tetracyclic N-hetereocycle widely found as the core structure in akuammiline alkaloids.
- Chen, Yi,Gao, Lu,Song, Xuanyi,Song, Zhenlei
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supporting information
p. 124 - 128
(2021/01/13)
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- Synthesis of Bidentate Nitrogen Ligands by Rh-Catalyzed C-H Annulation and Their Application to Pd-Catalyzed Aerobic C-H Alkenylation
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A new class of bidentate ligands was prepared by a modular approach involving Rh-catalyzed C-H annulation reactions. The resulting conformationally constrained ligands enabled the Pd-catalyzed C-H alkenylation at electron-rich and sterically less hindered positions of electron-rich arenes while promoting the facile oxidation of Pd(0) intermediates by oxygen. This newly introduced ligand class is complementary to the ligands developed for Pd-catalyzed oxidative reactions and may find broad application in transition-metal-catalyzed reactions.
- Kim, Hyun Tae,Kang, Eunsu,Kim, Minkyu,Joo, Jung Min
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supporting information
p. 3657 - 3662
(2021/05/10)
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- Synthesis, in vitro cytotoxicity, and molecular docking study of novel 3,4-dihydroisoquinolin-1(2H)-one based piperlongumine analogues
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With the aim of expanding the scope of SAR on piperlongumine (PL), a naturally occurring anticancer molecule, we have designed a novel hybrid molecule bearing 3,4-dihydroisoquinolin-1(2H)-one and trans-cinnamic acids. The structure, based on hybridization strategy, is used for hybridization of naturally occurring scaffolds. We have synthesized 14 hybrid molecules by coupling 3,4-dihydroisoquinolin-1(2H)-one core with cinnamic acids using the mix anhydride approach. The newly synthesized inhibitors were evaluated for cell viability against breast cancer MCF-7 and cervical cancer HeLa cell lines. Furthermore, the active compounds were screened for their potential in breast cancer MDA-MB-231, cervical cancer C33A cell lines, prostate cancer DU-145, PC-3, and normal VERO cells. From the series, compound 10g was seen to inhibit MCF-7 cell growth significantly with GI50 50 = 20 μM) and C33A (GI50 = 3.2 μM). While the inhibitor 10i inhibits MCF-7 breast cancer cell growth GI50 = 3.42 μM along with inhibition of cell growth in MDA-MB-231 (GI50 = 30 μM), HeLa (GI50 = 7.67 μM), C33A (GI50 = 13 μM), DU-145 (GI50 = 6.45 μM), PC-3 (GI50 = 8.68 μM), and VERO (GI50 = 2.93 μM), respectively. Furthermore, molecular docking study demonstrated these compounds could bind tightly to the colchicine domain of tubulin through a network of favorable steric and electrostatic interactions and thus act as a tubulin polymerization inhibitor.
- Kulkarni, Mahesh R.,Lad, Nitin P.,Khedkar, Vijay M.,Gaikwad, Nitin D.
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p. 1359 - 1370
(2021/04/09)
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- Boron-Templated Dimerization of Allylic Alcohols to Form Protected 1,3-Diols via Acid Catalysis
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We report an unprecedented boron-templated dimerization of allylic alcohols that generates a 1,3-diol product with two stereogenic centers in high yield and diastereoselectivity. This acid-catalyzed reaction is achieved via in situ formation of a boronic ester intermediate that facilitates selective cyclization and formation of a cyclic boronic ester product. High yields are observed with a variety of allylic alcohols, and mechanistic studies confirm the role of boron as a template for the reaction.
- Nazari, S. Hadi,Forson, Kelton G.,Martinez, Erin E.,Hansen, Nicholas J.,Gassaway, Kyle J.,Lyons, Nathan M.,Kenney, Karissa C.,Valdivia-Berroeta, Gabriel A.,Smith, Stacey J.,Michaelis, David J.
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supporting information
p. 9589 - 9593
(2019/12/02)
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- Arene Trifunctionalization with Highly Fused Ring Systems through a Domino Aryne Nucleophilic and Diels–Alder Cascade
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A convenient and efficient domino aryne process was developed under transition-metal-free conditions to generate a range of tetra- and pentacyclic ring systems. This transformation was realized via a 1,2-benzdiyne through a nucleophilic and Diels–Alder reaction cascade using styrene as the diene moiety. Three new chemical bonds, namely one C?N and two C?C bonds, and two benzofused rings could be constructed concomitantly, which was made possible by distinct chemoselective control at both the 1,2-aryne and 2,3-aryne stages. Moreover, in-depth studies were carried out on the domino aryne precursors and controlling the diastereoselectivity.
- He, Jia,Jia, Zizi,Tan, Hongcheng,Luo, Xiaohua,Qiu, Dachuan,Shi, Jiarong,Xu, Hai,Li, Yang
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supporting information
p. 18513 - 18518
(2019/11/19)
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- Highly Enantioselective Synthesis of Functionalized Glutarimide Using Oxidative N-Heterocyclic Carbene Catalysis: A Formal Synthesis of (?)-Paroxetine
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A simple yet highly effective approach toward enantioselective synthesis of trans-3,4-disubstituted glutarimides from readily available starting materials is developed using oxidative N-heterocyclic carbene catalysis. The catalytic reaction involves a formal [3 + 3] annulation between enals and substituted malonamides enabling the production of glutarimide derivatives in a single chemical operation via concomitant formation of C-C and C-N bonds. The reaction offers easy access to a broad range of functionalized glutarimides with excellent enantioselectivity and good yield. Synthetic application of the method is demonstrated via formal synthesis of (?)-paroxetine and other bioactive molecules.
- Porey, Arka,Santra, Surojit,Guin, Joyram
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supporting information
p. 5313 - 5327
(2019/04/16)
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- Fabrication of Pd/CuFe2O4 hybrid nanowires: A heterogeneous catalyst for Heck couplings
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The development of environmentally benign transformations is indispensable in organic synthesis. Herein, a hybrid heterogeneous catalyst, palladium(0) on copper ferrite nanowires, has been synthesized, characterized, and for the first time, employed in the Jeffrey Heck reaction between iodoarenes and allylic alcohols, and good to excellent yields have been obtained. In addition, the catalyst was found to be suitable for the usual Heck coupling. The nanocatalyst was recovered and reused up-to multiple runs without any noticeable loss of its catalytic activity.
- Lakshminarayana,Mahendar,Ghosal,Sreedhar,Satyanarayana,Subrahmanyam, Ch.
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p. 1646 - 1654
(2018/02/09)
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- Ligand-accelerated non-directed C-H functionalization of arenes
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The directed activation of carbon-hydrogen bonds (C-H) is important in the development of synthetically useful reactions, owing to the proximity-induced reactivity and selectivity that is enabled by coordinating functional groups. Palladium-catalysed non-directed C-H activation could potentially enable further useful reactions, because it can reach more distant sites and be applied to substrates that do not contain appropriate directing groups; however, its development has faced substantial challenges associated with the lack of sufficiently active palladium catalysts. Currently used palladium catalysts are reactive only with electron-rich arenes, unless an excess of arene is used, which limits synthetic applications. Here we report a 2-pyridone ligand that binds to palladium and accelerates non-directed C-H functionalization with arene as the limiting reagent. This protocol is compatible with a broad range of aromatic substrates and we demonstrate direct functionalization of advanced synthetic intermediates, drug molecules and natural products that cannot be used in excessive quantities. We also developed C-H olefination and carboxylation protocols, demonstrating the applicability of our methodology to other transformations. The site selectivity in these transformations is governed by a combination of steric and electronic effects, with the pyridone ligand enhancing the influence of sterics on the selectivity, thus providing complementary selectivity to directed C-H functionalization.
- Wang, Peng,Verma, Pritha,Xia, Guoqin,Shi, Jun,Qiao, Jennifer X.,Tao, Shiwei,Cheng, Peter T. W.,Poss, Michael A.,Farmer, Marcus E.,Yeung, Kap-Sun,Yu, Jin-Quan
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p. 489 - 493
(2017/11/28)
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- S,O-Ligand-Promoted Palladium-Catalyzed C-H Functionalization Reactions of Nondirected Arenes
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Pd(II)-catalyzed C-H functionalization of nondirected arenes has been realized using an inexpensive and easily accessible type of bidentate S,O-ligand. The catalytic system shows high efficiency in the C-H olefination reaction of electron-rich and electron-poor arenes. This methodology is operationally simple, scalable, and can be used in late-stage functionalization of complex molecules. The broad applicability of this catalyst has been showcased in other transformations such as Pd(II)-catalyzed C-H acetoxylation and allylation reactions.
- Naksomboon, Kananat,Valderas, Carolina,Gómez-Martínez, Melania,álvarez-Casao, Yolanda,Fernández-Ibá?ez, M. ángeles
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p. 6342 - 6346
(2017/09/15)
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- Silver-Catalyzed Cross-Olefination of Donor and Acceptor Diazo Compounds: Use of N-Nosylhydrazones as Diazo Surrogate
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The cross-olefination reaction of donor and acceptor diazo compounds was explored. The use of N-nosylhydrazones as diazo surrogates and the dependence on silver catalysis were crucial for the reaction development. A variety of (hetero)aryl N-nosylhydrazones and α-diazo esters, amides, and phosphonates were compatible, and the functionalized alkene products were afforded in good to high yields with moderate (Z)/(E) selectivities. The experimental and DFT calculation results suggest that the cross-selectivity is due to selective activation of the silver catalyst for donor diazo compounds.
- Liu, Zhaohong,Liu, Binbin,Zhao, Xue-Feng,Wu, Yan-Bo,Bi, Xihe
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supporting information
p. 928 - 932
(2017/02/15)
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- Bioactivity and structure-activity relationship of cinnamic acid esters and their derivatives as potential antifungal agents for plant protection
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A series of cinnamic acid esters and their derivatives were synthesized and evaluated for antifungal activities in vitro against four plant pathogenic fungi by using the mycelium growth rate method. Structure-activity relationship was derived also. Almost all of the compounds showed some inhibition activity on each of the fungi at 0.5 mM. Eight compounds showed the higher average activity with average EC50 values of 17.4-28.6 μg/mL for the fungi than kresoxim-methyl, a commercial fungicide standard, and ten compounds were much more active than commercial fungicide standards carbendazim against P. grisea or kresoxim-methyl against both P. grisea and Valsa Mali. Compounds C1 and C2 showed the higher activity with average EC50 values of 17.4 and 18.5 μg/mL and great potential for development of new plant antifungal agents. The structure-activity relationship analysis showed that both the substitution pattern of the phenyl ring and the alkyl group in the alcohol moiety significantly influences the activity. There exists complexly comprehensive effect between the substituents on the phenyl ring and the alkyl group in the alcohol moiety on the activity. Thus, cinnamic acid esters showed great potential the development of new antifungal agents for plant protection due to high activity, natural compounds or natural compound framework, simple structure, easy preparation, low-cost and environmentally friendly.
- Zhou, Kun,Chen, Dongdong,Li, Bin,Zhang, Bingyu,Miao, Fang,Zhou, Le
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- Discovery of synthetic methoxy-substituted 4-phenylbutyric acid derivatives as chemical chaperones
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In this study, we evaluated the chemical chaperone activity of synthetic 4-phenylbutyric acid (4-PBA) derivatives. These derivatives have a methoxy group at the benzene ring and/or longer or shorter fatty acid portions. Several 4-PBA derivatives demonstrated higher antiaggregation activity than 4-PBA. Moreover, 4-(4-methoxyphenyl)butanoic acid (7b) showed protective effects against endoplasmic reticulum stress-induced neuronal cell death.
- Mimori, Seisuke,Okuma, Yasunobu,Kaneko, Masayuki,Kawada, Koichi,Nomura, Yasuyuki,Murakami, Yasuoki,Hamana, Hiroshi
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supporting information
p. 1051 - 1052
(2013/09/24)
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- Synthesis of some phenylpropanoid glycosides (PPGs) and their acetylcholinesterase/xanthine oxidase inhibitory activities
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In this research, three categories of phenylpropanoid glycosides (PPGs) were designed and synthesized with PPGs isolated from Rhodiola rosea L. as lead compounds. Their inhibitory abilities toward acetylcholinesterase (AChE) and xanthine oxidase (XOD) were also tested. Some of the synthetic PPGs exhibited excellent enzyme inhibitory abilities.
- Li, Xiao-Dong,Kang, Shuai-Tao,Li, Guo-Yu,Li, Xian,Wang, Jin-Hui
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experimental part
p. 3580 - 3596
(2011/07/07)
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- Structure mechanism insights and the role of nitric oxide donation guide the development of oxadiazole-2-oxides as therapeutic agents against schistosomiasis
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Schistosomiasis is a chronic parasitic disease affecting hundreds of millions of individuals worldwide. Current treatment depends on a single agent, praziquantel, raising concerns of emergence of resistant parasites. Here, we continue our explorations of an oxadiazole-2-oxide class of compounds we recently identified as inhibitors of thioredoxin glutathione reductase (TGR), a selenocysteine-containing flavoenzyme required by the parasite to maintain proper cellular redox balance. Through systematic evaluation of the core molecular structure of this chemotype, we define the essential pharmacophore, establish a link between the nitric oxide donation and TGR inhibition, determine the selectivity for this chemotype versus related reductase enzymes, and present evidence that these agents can be modified to possess appropriate drug metabolism and pharmacokinetic properties. The mechanistic link between exogenous NO donation and parasite injury is expanded and better defined. The results of these studies verify the utility of oxadiazole-2-oxides as novel inhibitors of TGR and as efficacious antischistosomal agents. 2009 American Chemical Society.
- Rai, Ganesha,Sayed, Ahmed A.,Lea, Wendy A.,Luecke, Hans F.,Chakrapani, Harinath,Prast-Nielsen, Stefanie,Jadhav, Ajit,Leister, William,Shen, Min,Inglese, James,Austin, Christopher P.,Keefer, Larry,Arnér, Elias S. J.,Simeonov, Anton,Maloney, David J.,Williams, David L.,Thomas, Craig J.
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supporting information; experimental part
p. 6474 - 6483
(2010/03/31)
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- Practical one-pot syntheses of ethyl 4-substituted-1 H-pyrrole-3- carboxylates from aldehydes
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Ethyl 4-substituted-1H-pyrrole-3-carboxylates were prepared in a one-pot manner starting from aromatic or aliphatic aldehydes via a Horner-Wadsworth- Emmons reaction and subsequent reaction with tosylmethylisocyanide (TosMIC) in the presence of sodium tert-amylate in toluene. Judicious selection of base and solvent led to the use of a single solvent, i.e., toluene, for reactions as well as for crystallization to render the one-pot process more practical and greener than the stepwise version. hisin@ lels.com.
- Chang, Jay Hyok,Shin, Hyunik
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p. 291 - 293
(2013/01/03)
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- Preparation of active and robust palladium nanoparticle catalysts stabilized by diamine-functionalized mesoporous polymers
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A two-step chemical modification process is designed for synthesizing novel diamine-functionalized mesopolymers, which combine the advantage of organic polymers and mesoporous materials, and serve as an efficient scaffold for supporting highly dispersed, catalytically active and robust Pd nanoparticles (NPs). The Royal Society of Chemistry 2008.
- Xing, Rong,Liu, Yueming,Wu, Haihong,Li, Xiaohong,He, Mingyuan,Wu, Peng
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supporting information; scheme or table
p. 6297 - 6299
(2009/04/13)
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- Inhibition of uridine phosphorylase: Synthesis and structure-activity relationships of aryl-substituted 5-benzyluracils and 1-[(2- hydroxyethoxy)methyl]-5-benzyluracils
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A series of 1-[(2-hydroxyethoxy)methyl]-5-benzyluracils were synthesized and tested for inhibition of murine liver uridine phosphorylase (UrdPase). Inhibitors of UrdPase are reported to enhance the chemotherapeutic utility of 5-fluoro-2'-deoxyuridine and 5-fluorouracil and to ameliorate zidovudine- induced anemia in animal models. We prepared a series of 5-aryl-substituted analogues of 5-benzylacyclouridine (BAU), a good inhibitor of UrdPase (IC50 of 0.46 μM), to develop a compound with enhanced potency and improved pharmacokinetics. The first phase of structure-activity relationship studies on a series of 32 aryl-substituted 5-benzyluracils found several 5-(3- alkoxybenzyl) analogues of 5-benzyluracil with enhanced potency. The acyclovir side chain, the (2-hydroxyethoxy)methyl group, was substituted on the more potent aryl-substituted 5-benzyluracils. The two most potent compounds, 10y (3-propoxy) and 10dd (3-sec-butoxy), were inhibitors of UrdPase with IC50s of 0.047 and 0.027 μM, respectively. Six compounds were tested in vivo for effects on steady-state concentrations of circulating uridine in rats. Plasma uridine levels were elevated 3-9-fold by compound levels that ranged from 8 to 50 μM.
- Orr,Musso,Boswell,Kelley,Joyner,Davis,Baccanari
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p. 3850 - 3856
(2007/10/02)
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