- Synergistic Cooperative Effect of L-Arginine-[bmim]Br in Cascade Decarboxylative Knoevenagel-Thia-Michael Addition Reactions: Green Approach Towards C?S Bond Formation with In Situ Generated Unactivated α,β-Unsaturated Ester
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In this report, a synergistic combination of L-arginine and [bmim]Br has been realized for the first time towards step-economical synthesis of β-aryl-β-sulfanyl esters from aromatic aldehyde, malonate and thiol via cascade thia-Michael addition reaction on in situ formed unactivated β-aryl-α,β-unsaturated esters (via decarboxylative Knoevenagel reaction) under metal-and acid/base-free conditions. Furthermore, the gram scalability and recyclability of the catalytic system (up to 5 cycles) makes our one-pot two-step protocol more economically efficient and synthetically attractive for cascade C?C and C?S bond formation than traditional two-step methods. The synergistic interaction of the catalytic system i. e. L-arginine with [bmim]Br has been probed by NMR (1H and 13C) studies. (Figure presented.).
- Singh, Richa,Thopate, Yogesh,Equbal, Danish,Sinha, Arun K.
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Read Online
- Concise and efficient synthesis of cinepazide
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An efficient synthesis of cinepazide has been carried out in four steps with an overall yield of 51%. The synthesis was started from a commercially available 3,4,5-tri-methoxy benzaldehyde. All the reactions were very clean and the isolation of products was also very easy.
- Nagaiah,Narsaiah, A. Venkat
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Read Online
- First synthesis of tabamides A–C and their derivatives: In vitro nitric oxide inhibitory activity
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The first synthesis of natural phenolic amides, tabamides A–C (1–3), and their derivatives (4–12) was accomplished using Stobbe condensation and amide coupling reactions as key steps. The in vitro nitric oxide (NO) inhibitory effects of these compounds in LPS-induced RAW-264.7 macrophages were evaluated as an indicator of anti-inflammatory activity. All compounds tested had a concentration-dependent inhibitory effect on NO production by RAW-264.7 macrophages without significant cytotoxicity. Compound 6, a tabamide A derivative (IC50 = 82.6 μM), followed by tabamide A (1, IC50 = 100.7 μM), was the most potent from the series. The present study revealed that tabamide A (1) could be considered as a lead structure to develop NO production-targeted anti-inflammatory agents.
- Damodar, Kongara,Jeon, Sung Ho,Lee, Jeong Tae,Shin, Sooyong
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supporting information
(2021/11/10)
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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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- Synthesis method of beta-chloro acid ester and alpha, beta-unsaturated acid ester compound
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The invention belongs to the technical field of organic chemistry, and particularly relates to a synthesis method of beta-chloro acid ester and an alpha, beta-unsaturated acid ester compound. The structure of the compound is characterized by 1H NMR and 13C NMR and is confirmed. The method comprises the steps of by taking acetonitrile as a solvent, carrying out fragmentation on olefin, chlorooxalic acid monoester and 2, 6-dimethyl pyridine under a photocatalytic condition to generate an alkoxyacyl free radical intermediate, carrying out free radical addition reaction on the alkoxyacyl free radical intermediate and the olefin to generate carbon free radicals, then carrying out chlorination reaction to obtain the beta-chloro acid ester compound, and carrying out dehydrochlorination reaction under a DBU condition to generate the alpha, beta-unsaturated acid ester compound. The preparation method of the compound disclosed by the invention has the advantages of starting from olefin, being mild in condition, simple and efficient, strong in functional group compatibility and wide in substrate application range, and various beta-chloro acid ester and alpha, beta-unsaturated acid ester compounds can be synthesized from highly commercialized raw materials. On the basis of photoreaction of fluid chemistry, a target product can also be obtained with a relatively good yield, and the method has very good industrial and medicinal chemistry application values.
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Paragraph 0103-0107
(2021/08/11)
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- Hypervalent iodine(iii) induced oxidative olefination of benzylamines using Wittig reagents
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We have developed hypervalent iodine(iii) induced oxidative olefination of primary and secondary benzylamines using 2C-Wittig reagents, which provides easy access to α,β-unsaturated esters. Mild reaction conditions, good to excellent yields with high (E) selectivity, and a broad substrate scope are the key features of this reaction. We have successfully carried out the gram-scale synthesis of α,β-unsaturated esters.
- Ramavath, Vijayalakshmi,Rupanawar, Bapurao D.,More, Satish G.,Bansode, Ajay H.,Suryavanshi, Gurunath
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p. 8806 - 8813
(2021/05/26)
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- A de novo peroxidase is also a promiscuous yet stereoselective carbene transferase
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By constructing an in vivo-assembled, catalytically proficient peroxidase, C45, we have recently demonstrated the catalytic potential of simple, de novo-designed heme proteins. Here, we show that C45's enzymatic activity extends to the efficient and stereoselective intermolecular transfer of carbenes to olefins, heterocycles, aldehydes, and amines. Not only is this a report of carbene transferase activity in a completely de novo protein, but also of enzyme-catalyzed ring expansion of aromatic heterocycles via carbene transfer by any enzyme.
- Stenner, Richard,Steventon, Jack W.,Seddon, Annela,Anderson, J.L. Ross
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p. 1419 - 1428
(2020/01/28)
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- Accessing dihydro-1,2-oxazine via cloke-wilson-type annulation of cyclopropyl carbonyls: application toward the diastereoselective synthesis of pyrrolo[1,2- b][1,2]oxazine
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A convenient additive-free synthesis of dihydro-4H-1,2-oxazines via a Cloke-Wilson-type ring expansion of the aryl-substituted cyclopropane carbaldehydes with the hydroxylamine salt is introduced. Comparatively less active cyclopropyl ketones also follow a similar protocol if supplemented by catalytic p-toluene sulfonic acid monohydrate. The transformation is performed in an open-to-air flask as it shows negligible sensitivity toward air/moisture. Dihydro-4H-1,2-oxazines when subjected to cycloaddition with the cyclopropane diester afford a trouble-free formulation of the valued hexahydro-2H-pyrrolo[1,2-b][1,2]oxazine derivatives. A cascade one-pot variant of this two-step strategy offers a comparable overall yield of the final product.
- Banerjee, Prabal,Kumar, Pankaj,Kumar, Rakesh
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supporting information
p. 6535 - 6550
(2020/06/09)
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- Asymmetric total synthesis of dihydroisocoumarins: 6-methoxymellein, kigelin and fusarentin 6, 7 dimethyl ether by employing proline catalysed asymmetric α-aminoxylation
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A concise asymmetric total synthesis of dihydroisocoumarins such as 6-methoxymellein, kigelin and fusarentin 6,7-dimethyl ether in high enantiopurity have been achieved from non-chiral aldehydes by employing proline catalysed asymmetric α-aminoxylation reaction. The required stereochemistry of hydroxyl group have been generated by alternating L or D proline as a organocatalyst in α-aminoxylation step and lactone ring is assembled by oxa-Pictet-Spengler cyclisation reaction as the key steps.
- Mane, Baliram B.,Markad, Sachin B.,Waghmode, Suresh B.
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- Iron-Catalyzed Cross-Coupling of Bis-(aryl)manganese Nucleophiles with Alkenyl Halides: Optimization and mechanistic investigations
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Various substituted bis-(aryl)manganese species were prepared from aryl bromides by one-pot insertion of magnesium turnings in the presence of LiCl and in situ trans-metalation with MnCl2 in THF at ?5 ?C within 2 h. These bis-(aryl)manganese reagents undergo smooth iron-catalyzed cross-couplings using 10 mol% Fe(acac)3 with various functionalized alkenyl iodides and bromides in 1 h at 25 ?C. The aryl-alkenyl cross-coupling reaction mechanism was thoroughly investigated through paramagnetic 1H-NMR, which identified the key role of tris-coordinated ate-iron(II) species in the catalytic process.
- Rousseau, Lidie,Desaintjean, Alexandre,Knochel, Paul,Lefèvre, Guillaume
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supporting information
(2020/02/18)
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- Preparation method for cinepazide maleate
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The invention provides a preparation method for cinepazide maleate, which comprises the following steps of: (1) carrying out Wittig reaction on 3, 4, 5-trimethoxybenzaldehyde serving as an initial rawmaterial and phosphine ylide to obtain (E)-3, 4, 5-trimethoxyethyl cinnamate (intermediate I), (2) hydrolyzing the (E)-3, 4, 5-trimethoxyethyl cinnamate to obtain a key intermediate 3, 4, 5-trimethoxy cinnamic acid (intermediate II), (3) in the presence of 1-hydroxybenzotriazole, triethylamine and carbodiimide hydrochloride, coupling the intermediate I with anhydrous piperazine to synthesize 1-(3, 4, 5-trimethoxycinnamoyl) piperazine (intermediate III), (4) reacting the 1-(3, 4, 5-trimethoxycinnamoyl) piperazine with 2-bromo-1 (pyrrolidine-1-yl) ethyl ketone to generate cinepazide (an intermediate IV), and (5) salifying the cinepazide in the step (4) and maleic acid to generate the target product cinepazide maleate. The preparation method has the advantages of cheap and easily available raw materials, simple operation, short production period, high yield, easy purification, good control of the product quality, reduction of the pollutant discharge, environmental protection, and realization of industrial production.
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Paragraph 0032
(2020/04/17)
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- Excavating precursors from the traditional Chinese herb Polygala tenuifolia and Gastrodia elata: Synthesis, anticonvulsant activity evaluation of 3,4,5-trimethoxycinnamic acid (TMCA)ester derivatives
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Epilepsy is a group of neurological disorders characterized by recurrent seizures that disturbs about 60 million people worldwide. In this article, a novel series of 3,4,5-trimethoxycinnamic acid (TMCA)ester derivatives 1–35 were designed inspired from the traditional Chinese herb pair drugs Polygala tenuifolia and Gastrodia elata and synthesized followed by in vivo and in silico evaluation of their anticonvulsant potential. All the synthesized derivatives were biologically evaluated for their anticonvulsant potential using two acute model of seizures induced in mice, the maximal electroshock (MES)and sc-pentylenetetrazole (PTZ)models. Simultaneously, the motor impairment as a surrogate of acute neurotoxicity and in vitro screening of cytotoxicity against HepG-2 cells line were assessed through the rotarod performance test and CCK-8 assay, respectively. In addition, the physicochemical and pharmacokinetic parameters of the active compounds were determined. Our results showed that compounds 5, 7, 8, 13, 20, 25, 28, 30 and 32 exhibited preferable anticonvulsant activity in primary evaluation, with compounds 28 and 32 being the most promising anticonvulsant agents in according to results of subsequent pharmacology and toxicity evaluation. Additionally, the molecular modeling experiments predicted good binding interactions of part of the obtained active molecules with the gamma-aminobutyric acid (GABA)transferas. Therefore, it could be concluded that the synthesized derivatives 28 and 32 would represent useful lead compounds for further investigation in the development of anticonvulsant agents.
- Zhao, Zefeng,Bai, Yajun,Xie, Jing,Chen, Xufei,He, Xirui,Sun, Ying,Bai, Yujun,Zhang, Yangyang,Wu, Shaoping,Zheng, Xiaohui
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- Design, Antileishmanial Activity, and QSAR Studies of a Series of Piplartine Analogues
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Piplartine is an alkamide found in different Piper species and possesses several biological activities, including antiparasitic properties. Thus, the aim of the present study was to evaluate a series of 32 synthetic piplartine analogues against the Leishmania amazonensis promastigote forms and establish the structure-activity relationship and 3D-QSAR of these compounds. The antileishmanial effect of the compounds was determined using the MTT method. Most compounds were found to be active against L. amazonensis. Among 32 assayed derivatives, compound (E)-(-)-bornyl 3-(3,4,5-trimethoxyphenyl)-acrylate exhibited the most potent antileishmanial activity (IC50 = 0.007 ± 0.008 μM, SI > 10), followed by benzyl 3,4,5-trimethoxybenzoate (IC50 = 0.025 ± 0.009 μM, SI > 3.205) and (E)-furfuryl 3-(3,4,5-trimethoxyphenyl)-acrylate (IC50 = 0.029 ± 0.007 μM, SI > 2.688). It was found that the rigid substituents contribute to increasing antiparasitic activity against L. amazonensis promastigotes. The presence of the unsaturated heterocyclic substituent in the phenylpropanoid chemical structure (furfuryl group) resulted in a bioactive derivative. Molecular simplification of benzyl 3,4,5-trimethoxybenzoate by omitting the spacer group contributed to the bioactivity of this compound. Furthermore, bornyl radical appears to be important for antileishmanial activity, since (E)-(-)-bornyl 3-(3,4,5-trimethoxyphenyl)-acrylate exhibited the most potent antileishmanial activity. These results show that some derivatives studied would be useful as prototype molecules for the planning of new derivatives with profile of antileishmanial drugs.
- Nóbrega, Flávio R.,Silva, Larisse V.,Bezerra Filho, Carlos Da Silva M.,Lima, Tamires C.,Castillo, Yunierkis P.,Bezerra, Daniel P.,Lima, Tatjana K. Souza,Sousa, Dami?o P. De
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- Synthesis of Functionalized Indolines and Dihydrobenzofurans by Iron and Copper Catalyzed Aryl C-N and C-O Bond Formation
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A simple and effective one-pot, two-step intramolecular aryl C-N and C-O bond forming process for the preparation of a wide range of benzo-fused heterocyclic scaffolds using iron and copper catalysis is described. Activated aryl rings were subjected to a highly regioselective, iron(III) triflimide-catalyzed iodination, followed by a copper(I)-catalyzed intramolecular N-or O-arylation step leading to indolines, dihydrobenzofurans, and six-membered analogues. The general applicability and functional group tolerance of this method were exemplified by the total synthesis of the neolignan natural product, (+)-obtusafuran. DFT calculations using Fukui functions were also performed, providing a molecular orbital rationale for the highly regioselective arene iodination process.
- Henry, Martyn C.,Senn, Hans Martin,Sutherland, Andrew
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p. 346 - 364
(2019/01/08)
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- Synthesis and biological evaluation of 4-arylcoumarins as potential anti-Alzheimer's disease agents
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Alzheimer's disease (AD) is a progressive neurological degenerative disease that has complex pathogenesis. A variety of studies in humans indicate that several enzymes inhibitors can be useful in the treatment of AD, including acetylcholinesterase (AchE), butyrylcholinesterase (BuChE) and monoamine oxidase (MAO). Various substituted 4-arylcoumarin derivatives were synthesised, and their activity in vitro were investigated, including AChE/BuChE inhibitory activity, MAO inhibitory activity, and antioxidant activity. Most of the compounds were found to exhibit high inhibitory activity, and individual compounds have extremely excellent activities. Therefore 4-arylcoumarins provides an idea for drugs design for the development of therapeutic or preventive agents for AD.
- Miao, Yuhang,Sun, Jie,Wang, Xiaojing,Yang, Jie,Yun, Yinling
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- METHOD FOR THE SYNTHESIS AND PURIFICATION OF ARYL ACID ESTERS
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The general inventive concepts are directed to the discovery that certain aryl acids can be esterified under particular conditions to provide the resulting ester as a solid that precipitates in good yield from the reaction mixture. The esters may then be isolated and purified with relative ease. Accordingly, a method for the esterification, isolation, and purification of aryl acids is provided.
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Paragraph 0029-0030
(2019/10/17)
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- Mild, Metal-Free and Protection-Free Transamidation of N-Acyl-2-piperidones to Amino Acids, Amino Alcohols and Aliphatic Amines and Esterification of N-Acyl-2-piperidones
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Amides are indispensable building blocks of biological systems, pharmaceuticals, and materials. We report a highly selective method for the synthesis of amides via transamidation process. Transamidation of N-acyl-2-piperidones with a broad range of amines is demonstrated under exceedingly mild and metal-free reaction condition that relies on the amide bond twist to weaken the amidic resonance. Transamidation proceeds under the neat condition at room temperature, in short reaction times (30–90 min) with good yields. Considerable variation is tolerated with both amine and imide substrates. Of note, amines bearing carboxylic acids (glycine and serine) and hydroxyl groups (dopamine, tyramine, etc.) are well tolerated which are otherwise problematic under the metal-catalyzed protocol. Our current method is applicable for transamidation of both alkyl and aryl-N-acyl-2-piperidones. The practical value of the method is highlighted by the synthesis of four natural product amide alkaloids in high yields under mild reaction conditions. In the absence of nucleophilic amines, N-acyl-2-piperidones undergoes esterification with EtOH at elevated temperature. Single crystal X-ray analysis of an N-acyl-2-piperidone shows amide bond twist, τ = –20.39° and pyramidalization, χN = –11.73°. This weakens the amidic conjugation and might be the factor controlling the reactivity and selectivity of these imides. We envision that the N-acyl-2-piperidone scaffold would be useful in the synthesis of pharmaceuticals and materials.
- Subramani, Muthuraman,Rajendran, Saravana Kumar
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p. 3677 - 3686
(2019/06/08)
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- Piplartine analogues and cytotoxic evaluation against glioblastoma
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Piplartine (1) is an alkamide extracted from plants of the genus Piper which shows several pharmacological properties, including antitumor activity. To improve this activity, a series of analogues based on 1 have been synthesized by esterification and amidation using the 3,4,5-trimethoxycinnamic acid-like starting material. During the study, the moieties 3-(3,4,5-trimethoxyphenyl)acrylate and 3-(3,4,5-trimethoxyphenyl)acrylamide were maintained on esters and amides respectively. Meanwhile, functional changes were exploited, and it was revealed that the presence of two aromatic rings in the side-chain was important to improve the cytotoxic activity against the U87MG cell line, such as the compound (E)-benzhydryl 3-(3,4,5-trimethoxyphenyl)acrylate (10), an ester that exhibited strong cytotoxicity and a similar level of potency to that of paclitaxel, a positive control. Compound 10 had a marked concentration-dependent inhibitory effect on the viability of the U87MG cell line with apoptotic and oxidative processes, showing good potential for altering main molecular pathways to prevent tumor development. Moreover, it has strong bioavailability with non-genotoxic and non-cytotoxic properties on human blood cells. In conclusion, the findings of the present study demonstrated that compound 10 is a promising agent that may find applications combatting diseases associated with oxidative stress and as a prototype for the development of novel drugs used in the treatment of glioblastoma.
- da Nóbrega, Flávio Rogério,Ozdemir, Ozlem,Nascimento Sousa, Sheila Cristina S.,Barboza, Joice Nascimento,Turkez, Hasan,de Sousa, Dami?o Pergentino
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- Synthesis of cinnamic ester derivatives from Oxalis pes-caprae using immobilized Br?nsted dual acidic ionic liquid and microwaves
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An efficient and mild synthesis of three naturally occurring cinnamic ester derivatives (5, 6 and 7) isolated from methanol extract of Oxalis pes-caprae has been described, which show inhibitory effects on the germination and growth of Lactuca sativa. 3,4,5-Trimethoxybenzaldehyde (1) has been used as the starting material. Esterification reaction has been achieved via a novel approach using immobilized Bransted dual acidic ionic liquid and microwaves.
- Shallu,Sharma, Madan L.,Singh, Jasvinder
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p. 1385 - 1390
(2019/05/22)
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- Identification of N-Hydroxycinnamamide analogues and their bio-evaluation against breast cancer cell lines
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The present study demonstrates the identification of N-hydroxycinnamamide derivatives and their anticancer potential against human triple-negative breast cancer cell line MDA-MB?231, MCF-7 and non-malignant origin cell line, HEK-293 (human embryonic kidney). MTT assay was studied with HEK-293 cell line. Anticancer potential of the N-hydroxycinnamamide derivatives were compared with marked drug Tamoxifen through in vitro study. The compound numbers 3b and 3h exhibit most potent activity against antagonistic breast cancer cells (MDA-MB-231) with IC50 13μM and 5μM respectively. Compound 3h promotes DNA fragmentation and induction of apoptosis. Furthermore, loss of mitochondrial membrane potential induced by compound 3h. The major mechanism of compound 3h for anti-breast cancer activity was probably initiation of reactive oxygen species (ROS) in cancer cells thereby persuading apoptotic cell deaths in cancer cells.
- Shukla, Akhilesh Kumar,Hamidullah,Shrivash, Manoj Kumar,Tripathi, Vishwa Deepak,Konwar, Rituraj,Pandey, Jyoti
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p. 475 - 483
(2018/08/21)
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- Modular synthesis and biological investigation of 5-hydroxymethyl dibenzyl butyrolactones and related lignans
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Dibenzyl butyrolactone lignans are well known for their excellent biological properties, particularly for their notable anti-proliferative activities. Herein we report a novel, efficient, convergent synthesis of dibenzyl butyrolactone lignans utilizing the acyl-Claisen rearrangement to stereoselectively prepare a key intermediate. The reported synthetic route enables the modification of these lignans to give rise to 5-hydroxymethyl derivatives of these lignans. The biological activities of these analogues were assessed, with derivatives showing an excellent cytotoxic profile which resulted in programmed cell death of Jurkat T-leukemia cells with less than 2% of the incubated cells entering a necrotic cell death pathway.
- Davidson, Samuel J.,Pilkington, Lisa I.,Dempsey-Hibbert, Nina C.,El-Mohtadi, Mohamed,Tang, Shiying,Wainwright, Thomas,Whitehead, Kathryn A.,Barker, David
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- Bu 4 N + -Controlled Addition and Olefination with Ethyl 2-(Trimethylsilyl)acetate via Silicon Activation
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Catalytic Bu 4 NOAc as silicon activator of ethyl 2-(trimethylsilyl)acetate, in THF, was utilized for the synthesis of β-hydroxy esters, whereas employing catalytic Bu 4 NOTMS gave α,β-unsaturated esters. The established reaction conditions were applicable to a diverse range of aromatic, heteroaromatic, aliphatic aldehydes and ketones. Reactions were achieved at room temperature without taking any of the specialized precautions that are in place for other organometallics. A stepwise olefination pathway via silylated β-hydroxy esters with subsequent elimination to form the α,β-unsaturated ester has been demonstrated. The key to selective product formation lies in use of the weaker acetate activator which suppresses subsequent elimination whereas stronger TMSO - activator (and base) facilitates both addition and elimination steps. The use of tetrabutyl ammonium salts for both acetate and trimethylsilyloxide activators provide enhanced silicon activation when compared to their inorganic cation counterparts.
- Das, Manas,Manvar, Atul,Fox, Ian,Roberts, Dilwyn J.,O'Shea, Donal F.
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supporting information
p. 2401 - 2406
(2017/09/30)
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- Piperlongumine derived cyclic sulfonamides (sultams): Synthesis and in?vitro exploration for therapeutic potential against HeLa cancer cell lines
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A novel modification of piperlongumine is designed, bearing a cyclic sulphonamide (sultam) and its synthesis is described. For the first time herein we report the synthesis and biological evaluation of the natural product derived cyclic sulfonamides using Grubbs second generation catalyst (Grubbs II) via ring closing metathesis approach. Synthesis of a series of piperlongumine derived sultams is done in a moderate to good yield using Wittig reaction, Ring-Closing Metathesis (RCM) and, amide synthesis by using mixed anhydride, approach. All synthesized compounds were evaluated for anticancer activity and some demonstrated dose dependent reduction in HeLa cell growth. Of these 7, 10 and 14 significantly reduced the cell growth. Consequently their calculated GI50values were found to be 0.1 or 0.1?μM.
- Lad, Nitin P.,Kulkarni, Sarang,Sharma, Rajiv,Mascarenhas, Malcolm,Kulkarni, Mahesh R.,Pandit, Shivaji S.
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p. 870 - 878
(2016/12/18)
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- Design and synthesis of a series of serine derivatives as small molecule inhibitors of the SARS coronavirus 3CL protease
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Synthesis of serine derivatives having the essential functional groups for the inhibitor of SARS 3CL protease and evaluation of their inhibitory activities using SARS 3CL R188I mutant protease are described. The lead compounds, functionalized serine derivatives, were designed based on the tetrapeptide aldehyde and Bai's cinnamoly inhibitor, and additionally performed with simulation on GOLD softwear. Structure activity relationship studies of the candidate compounds were given reasonable inhibitors ent-3 and ent-7k against SARS 3CL R188I mutant protease. These inhibitors showed protease selectivity and no cytotoxicity.
- Konno, Hiroyuki,Wakabayashi, Masaki,Takanuma, Daiki,Saito, Yota,Akaji, Kenichi
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supporting information
p. 1241 - 1254
(2016/03/01)
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- BF3·OEt2-mediated: Syn -selective Meyer-Schuster rearrangement of phenoxy propargyl alcohols for Z -β-aryl-α,β-unsaturated esters
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Synthesis of Z-β-aryl-α,β-unsaturated esters from readily available 1-aryl-3-phenoxy propargyl alcohols is achieved via a BF3-mediated syn-selective Meyer-Schuster rearrangement under ambient conditions. The reaction mechanism is postulated to involve an electrophilic borylation of an allene intermediate as the key step to kinetically control the stereoselectivity.
- Puri, Surendra,Hari Babu, Madala,Sridhar Reddy, Maddi
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p. 7001 - 7009
(2016/07/30)
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- Divergent Gold(I)-Catalyzed Skeletal Rearrangements of 1,7-Enynes
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The gold(I) complex catalyzed cycloisomerization and skeletal rearrangement of 1,n-enynes (n=5-7) is a powerful methodology for the efficient synthesis of complex molecular architectures. In contrast to 1,6-enynes, readily accessible homologous 1,7-enynes are largely unexplored in such transformations. Here, the divergent skeletal rearrangement of all-carbon 1,7-enynes by catalysis with a cationic gold(I) complex is reported. Depending on electronic and steric factors, differently substituted 1,7-enynes react via different carbocations formed from a common gold carbene intermediate to yield on the one hand novel exocyclic allenes and on the other hand tricyclic hexahydro-anthracenes through a novel dehydrogenative Diels-Alder reaction. Two birds with a gold-stone! Divergent gold(I) catalysis unraveled a novel cycloisomerization and a dehydrogenative Diels-Alder reaction of 1,7-enynes.
- Mei?, Rebecca,Kumar, Kamal,Waldmann, Herbert
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supporting information
p. 13526 - 13530
(2015/09/22)
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- Highly trans-Selective Arylation of Achmatowicz Rearrangement Products by Reductive γ-Deoxygenation and Heck-Matsuda Reaction: Asymmetric Total Synthesis of (-)-Musellarins A-C and Their Analogues
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Fully functionalized pyranuloses derived from Achmatowicz rearrangement (AR) are versatile building blocks in organic synthesis. However, access to trans-2,6-dihydropyrans from pyranuloses remains underexplored. Herein, we report a new two-step trans arylation of AR products to access 2,6-trans-dihydropyranones. This new trans-arylation method built on numerous plausible, but unsuccessful, direct arylation reactions, including Ferrier-type and Tsuji-Trost-type reactions, was finally enabled by an unprecedented, highly regioselective γ-deoxygenation of AR products by using Zn/HOAc and a diastereoselective Heck-Matsuda coupling. The synthetic utility of the reaction was demonstrated in the first asymmetric total synthesis of (-)-musellarins A-C and 12 analogues in 11-12 steps. The brevity and efficiency of our synthetic route permitted preparation of enantiomerically pure musellarins and analogues (>20 mg) for preliminary cytotoxicity evaluation, which led us to identify two analogues with three-to-six times greater potency than the musellarins as promising new leads. O leaves, Ar comes: A highly regio- and diastereoselective trans-arylation of Achmatowicz rearrangement products by an unprecedented Zn-mediated reductive γ-deoxygenation and Heck-Matsuda reaction was developed for the efficient synthesis of trans-2-aryl-6-alkyl dihydropyranones (see scheme: L.A.=Lewis acid). The synthetic utility of this new method was further demonstrated in the first asymmetric total synthesis of (-)-musellarins A-C and 12 analogues in 11-12 steps.
- Li, Zhilong,Ip, Fanny C. F.,Ip, Nancy Y.,Tong, Rongbiao
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supporting information
p. 11152 - 11157
(2015/11/10)
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- Polyethyleneimine-Supported Triphenylphosphine and Its Use as a Highly Loaded Bifunctional Polymeric Reagent in Chromatography-Free One-Pot Wittig Reactions
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A polyethyleneimine-supported triphenylphosphine reagent has been synthesized and used as a highly loaded bifunctional homogeneous reagent in a range of one-pot Wittig reactions that afforded high yields of the desired products after simple purification procedures. The approach also served efficiently in tandem reaction sequences involving a one-pot Wittig reaction followed by conjugate reduction of the newly formed alkene product in situ. In these transformations, the phosphine oxide groups generated in the Wittig reaction served as the catalyst for activating trichlorosilane in the subsequent reduction reaction.
- Xia, Xuanshu,Toy, Patrick H.
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supporting information
p. 1737 - 1743
(2015/07/20)
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- First Enantioselective Synthesis of Surinamensinol B and a Non-Natural Polysphorin Analogue by a Two-Stereocentered Hydrolytic Kinetic Resolution
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An efficient and economical approach to the synthesis of antitumor and anti-inflammatory surinamensinol B (1) and antimalarial polysphorin analogue 2 has been achieved with high enantiomeric purity (96 % ee) by starting from commercially available 3,4,5-trimethoxybenzaldehyde. The key steps of the strategy include a Co-catalyzed two-stereocentered hydrolytic kinetic resolution (HKR) of racemic 2-[(methoxymethoxy)(3,4,5-trimethoxyphenyl)methyl]oxirane (13) as the chiral inducing step followed by a Mitsunobu reaction. Chiral epoxide 14 and chiral diol 15 were utilized in the syntheses of both compounds.
- Lalwani, Komal G.,Sudalai, Arumugam
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p. 7344 - 7351
(2015/11/25)
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- Ethyl cinnamate derivatives as promising high-efficient acaricides against Psoroptes cuniculi: Synthesis, bioactivity and structure-activity relationship
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This paper reported the synthesis, structure-activity relationship (SAR) and acaricidal activity in vitro against Psoroptes cuniculi, a mange mite, of 25 ethyl cinnamate derivatives. All target compounds were synthesized and elucidated by means of MS, 1H- and 13C-NMR analysis. The results showed that 24 out of 25 tested compounds at 1.0 mg/mL demonstrated acaricidal activity in varying degrees. Among them, 6, 15, 26, 27 and 30 showed significant activity with median lethal concentration values (LC50) of 89.3, 119.0, 39.2, 29.8 and 41.2 μg/mL, respectively, which were 2.1- to 8.3-fold the activity of ivermectin (LC50=247.4 μg/mL), a standard drug in the treatment of Psoroptes cuniculi. Compared with ivermectin, with a median lethal time value (LT50) of 8.9 h, 27 and 30 showed smaller LTM50 values of 7.9 and 1.3 h, respectively, whereas 6, 15 and 26 showed slightly larger LT50 values of 10.6, 11.0 and 10.4 h at 4.5 μmol/mL. SARs showed that the presence of o-NO2 or m-NO2 on the benzene ring significantly improved the activity, whereas the introduction of a hydroxy, methoxy, acetoxy, methylenedioxy, bromo or chloro group reduced the activity. (E)-Cinnamates were more effective than their (Z)-isomer. Nevertheless, the carbon-carbon double bond in the acrylic ester moiety was proven not to be essential to improve the activity of cinnamic acid esters. Thus, the results strongly indicate that cinnamate derivatives, especially their dihydro derivatives, should be promising candidates or lead compounds for the development of novel acaricides for the effective control of animal or human acariasis.
- Zhang, Bingyu,Lv, Chao,Li, Weibo,Cui, Zhiming,Chen, Dongdong,Cao, Fangjun,Miao, Fang,Zhou, Le
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p. 255 - 262
(2015/04/22)
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- Synthesis of neolignans as microtubule stabilisers
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Tubulin is a well established target for anticancer drug development. Lignans and neolignans were synthesized as tubulin interacting agents. Neolignans 10 and 19 exhibited significant anticancer activity against MCF-7 and MDAMB-231 human breast cancer cell lines. Both the compounds effectively induced stabilization of microtubule at 4 and 20 μM concentrations respectively. Neolignan 10 induced G2/M phase arrest in MCF-7 cells. Docking experiments raveled that 10 and 19 occupied the same binding pocket of paclitaxel with some difference in active site amino acids and good bioavailability of both the compounds. In in vivo acute oral toxicity 10 was well tolerated up to 300 mg/kg dose in Swiss-albino mice.
- Sathish Kumar,Singh, Aastha,Kumar, Amit,Singh, Jyotsna,Hasanain, Mohammad,Singh, Arjun,Masood, Nusrat,Yadav, Dharmendra K.,Konwar, Rituraj,Mitra, Kalyan,Sarkar, Jayanta,Luqman, Suaib,Pal, Anirban,Khan, Feroz,Chanda, Debabrata,Negi, Arvind S.
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p. 1342 - 1354
(2014/03/21)
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- COMPOUNDS FOR TREATMENT OF ANGIOGENESIS-MEDIATED DISEASES
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Synthetic cremastranone and cremastranone analogs are disclosed. Additionally, methods for synthesizing cremastranone and cremastranone analogs are disclosed. Methods of treating ocular neovascularization disorders and treating angiogenesis-mediated disease are also disclosed.
- -
-
Paragraph 0161-0163; sheet 4
(2014/12/09)
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- Synthesis and Evaluation of a Series of 3,4,5-Trimethoxycinnamic Acid Derivatives as Potential Antinarcotic Agents
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A series of 3,4,5-trimethoxycinnamic acid derivatives was prepared and evaluated for antinarcotic effects on morphine dependence in mice and binding affinities on serotonergic receptors. The key synthetic strategies involve generation of ketones 6-7, esters 9-12 through condensation reaction, and amides 13-19 via coupling reaction using 1-hydroxybenzotriazole/ethyl(dimethylaminopropryl)carbodiimide system in high yield. We found that the naloxone-induced morphine withdrawal syndrome was significantly suppressed by new synthetic 3,4,5-trimethoxycinnamic acid derivatives (20mg/kg/day). Most of 3,4,5-trimethoxycinnamic acid derivatives were found to have high affinity to 5-HT1A receptor. The naloxone-induced morphine withdrawal syndrome was attenuated by (+)8-OH-DPAT (0.1mg/kg/day, i.p.), a 5-HT1A receptor agonist. In cortical neuronal cells, (+)8-OH-DPAT (1μm) produced an elevation of the pERK 1/2 expression, and the elevated pERK levels were inhibited by WAY 100635, a 5-HT1A receptor-specific antagonist. Interestingly, the pERK levels were increased by the 3,4,5-trimethoxycinnamic acid derivatives and the derivatives-mediated changes in pERK levels were blocked by the WAY 100635. These results suggested that new synthetic 3,4,5-trimethoxycinnamic acid derivatives have a potential antinarcotic effect through acting as a 5-HT1A receptor agonist in mice.
- Jung, Jae-Chul,Moon, Sohyeon,Min, Dongguk,Park, Woo Kyu,Jung, Mankil,Oh, Seikwan
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p. 389 - 398
(2013/04/10)
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- Synthesis of methoxylated goniothalamin, aza-goniothalamin and γ-pyrones and their in vitro evaluation against human cancer cells
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The present work describes the preparation of three novel series of compounds based on the structure of goniothalamin, a natural styryl lactone which has been found to display cytotoxic and antiproliferative activities against a variety of cancer cell lines. A focused library of 29 novel goniothalamin analogues was prepared and evaluated against seven human cancer cell lines. While the γ-pyrones and the aza-goniothalamin analogues were less potent than the lead compound, 2,4-dimethoxy analogue 88 has shown to be more potent in vitro than goniothalamin against all cancer cell lines evaluated. Furthermore, it was more potent than doxorubicin against NCI-ADR/RES, OVCAR-03 and HT-29 while being less toxic to human keratinocytes (HaCat). The 3,5-dimethoxy analogue 90 and 2,4,5-trimethoxy analogue 92 also displayed promising antiproliferative activity when compared to goniothalamin (1). These results provide new elements for the design and synthesis of novel representatives of this family of natural compounds.
- Barcelos, Rosimeire Coura,Pastre, Julio Cezar,Caixeta, Vanessa,Vendramini-Costa, Débora Barbosa,De Carvalho, Jo?o Ernesto,Pilli, Ronaldo Aloise
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experimental part
p. 3635 - 3651
(2012/07/27)
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- Synthesis and biological evaluation of new piplartine analogues as potent aldose reductase inhibitors (ARIs)
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As a continuation of our efforts directed towards the development of anti-diabetic agents from natural sources, piplartine was isolated from Piper chaba, and was found to inhibit recombinant human ALR2 with an IC50 of 160 μM. To improve the efficacy, a series of analogues have been synthesized by modification of the styryl/aromatic and heterocyclic ring functionalities of this natural product lead. All the derivatives were tested for their ALR2 inhibitory activity, and results indicated that adducts 3c, 3e and 2j prepared by the Michael addition of piplartine with indole derivatives displayed potent ARI activity, while the other compounds displayed varying degrees of inhibition. The active compounds were also capable of preventing sorbitol accumulation in human red blood cells.
- Rao, Vidadala Ramasubba,Muthenna, Puppala,Shankaraiah, Gundeti,Akileshwari, Chandrasekhar,Babu, Kothapalli Hari,Suresh, Ganji,Babu, Katragadda Suresh,Chandra Kumar, Rotte Sateesh,Prasad, Kothakonda Rajendra,Yadav, Potharaju Ashok,Petrash, J. Mark,Reddy, Geereddy Bhanuprakash,Rao, Janaswamy Madhusudana
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p. 344 - 361
(2013/01/15)
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- Novel natural product-based cinnamates and their thio and thiono analogs as potent inhibitors of cell adhesion molecules on human endothelial cells
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In the present study, we report the design and synthesis of novel analogs of cinnamates, thiocinnamates and thionocinnamates and evaluated the potencies of these analogs to inhibit TNF-α induced ICAM-1 expression on human endothelial cells. By using whole cell-ELISA, our screening data demonstrated that ethyl 3′,4′,5′-trimethoxythionocinnamate (ETMTC) is the most potent inhibitor of TNF-α induced ICAM-1, VCAM-1 and E-selectin. As functional consequences, ETMTC abrogated TNF-α induced adhesion of neutrophils to the endothelial monolayer. Structure-activity relationship studies revealed the critical role of the chain-length of the alkyl group in the alcohol moiety, number of methoxy groups in the aromatic ring of the cinnamoyl moiety and the presence of the α, β- C-C double bond in the thiocinnamates and thionocinnamates.
- Kumar, Sarvesh,Singh, Brajendra K.,Arya, Pragya,Malhotra, Shashwat,Thimmulappa, Rajesh,Prasad, Ashok K.,Van Der Eycken, Erik,Olsen, Carl E.,Depass, Anthony L.,Biswal, Shyam,Parmar, Virinder S.,Ghosh, Balaram
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scheme or table
p. 5498 - 5511
(2011/12/15)
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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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- Synthesis of gingerol and diarylheptanoids
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The synthesis of gingerol 1 and related compounds 2-5 along with diarylheptanoids 6-8 has been accomplished using a Keck allylation, Crimmins' aldol reaction, aldehyde coupling with acetylene, and chelation controlled reductions as the key reactions. The absolute configuration of these molecules was confirmed by preparing their acetonide derivatives and by comparison of the NMR data with natural compounds.
- Sabitha, Gowravaram,Srinivas, Chitti,Reddy, Teega Rammohan,Yadagiri, Kurra,Yadav, Jhillu Singh
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experimental part
p. 2124 - 2133
(2012/03/27)
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- Formal total synthesis of (-)-raphidecursinol B
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An efficient enantioselective formal total synthesis of antimalarial natural product (-)-raphidecursinol B along with its all stereoisomers is described from commercially available 3,4,5-trimethoxybenzaldehyde using the Sharpless asymmetric dihydroxylation, regioselective α-tosylation, epoxide opening and Mitsunobu reaction as the key reaction steps.
- Das, Sanjit Kumar,Das, Sajal Kumar,Panda, Gautam
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scheme or table
p. 5100 - 5107
(2010/11/03)
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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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- Two variations of solvent-reduced wittig olefination reactions - Comparison of solventless wittig reactions to wittig reactions under ultrasonication with minimal work-up
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Stabilized and semi-stabilized phosphoranes can be subjected to solventless Wittig reactions with carbaldehydes. Simple heating of a mixture of added components at 100°C in an electric oven gives the corresponding olefins in good yield. Alternatively, the Wittig reactions can be carried out in a biphasic medium under ultrasonication. In this case, the Wittig products can be isolated by simple evaporation of the organic phase without additional work-up.
- Watanabe, Masataka,Morais, Goreti Ribeiro,Mataka, Shuntaro,Ideta, Keiko,Thiemann, Thies
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p. 909 - 915
(2007/10/03)
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- Free-radical-scavenging and xanthine oxidase inhibitory constituents from Stereospermum personatum
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Bioassay-guided fractionation of different extracts of both stem and stem bark of Stereospermum personatum led to the isolation of free-radical-scavenging and xanthine oxidase inhibitory molecules along with three new anthraquinones, sterequinones F-H (1-3), a new naphthoquinone, sterequinone I (4), two new phenethyl esters, 2(4′-hydroxyphenyl)ethyl undecanoate (14) and 2(4′-hydroxyphenyl)ethyl nonacosanoate (15), and a new 3,4,5-trimethoxycinnamyl ether, 2-methoxy-4-[3′-(3″,4″, 5″trimethoxyphenyl)allyloxymethyl]phenol (16), together with known compounds. The antioxidant and xanthine oxidase inhibitory potentials of the isolated compounds are reported.
- Sampath Kumar,Tiwari, Ashok K.,Venkat Reddy,Aparna,Jagadeeshwar Rao,Zehra Ali,Madhusudana Rao
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p. 1615 - 1621
(2008/09/17)
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- A microwave-accelerated esterification of α,β-unsaturated acids with alkyl or aryl carbonochloridate and triethylamine in acetonitrile as a novel esterifying reagent mixture
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An efficient synthesis of α,β-unsaturated esters by treatment of the corresponding acids with alkyl or aryl carbonochloridate, triethylamine, and acetonitrile was accomplished for the first time under microwave irradiation for 10 min. The esters 1b-24b were isolated in 71-97% yield.
- Pathania, Vinod,Sharma, Anuj,Sinha, Arun K.
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p. 811 - 816
(2007/10/03)
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- 1,3-Dipolar cycloaddition route to novel isoxazole-type derivatives related to combretastatin A-4
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A series of compounds related to combretastatin A-4, containing a five-membered heterocyclic ring interposed between the two phenyl groups have been prepared. Synthetic approach involves 1,3-dipolar cycloaddition of various 3,4,5-trimethoxyphenyl units with an in situ generated nitrile oxide from a suitable aldoxime using sodium hypochlorite. Depending on the nature of the dipolarophile, 3,5-diarylisoxazole derivatives were obtained along with the 3,4-regioisomeric isomers.
- Kaffy, Julia,Monneret, Claude,Mailliet, Patrick,Commer?on, Alain,Pontikis, Renée
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p. 3359 - 3362
(2007/10/03)
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- Radical cyclisation based approach to lignans. Synthesis of 4-arylmethyldihydrofuran-2-ones
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Bromoacetalisation of the cinnamyl alcohols 7a-d, obtained from the corresponding benzaldehydes, generated the bromoacetals 10a-d. The 5-exo trig radical cyclisation of the bromoacetals 10a-d followed by one step hydrolysis-oxidation of the resulting cyclic acetals 11a-d furnished the title compounds 6a-d, respectively, well-established intermediates of a variety of lignans.
- Srikrishna,Danieldoss
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p. 2357 - 2364
(2007/10/03)
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- Kinetic study of microwave-assisted Wittig reaction of stabilised ylides with aromatic aldehydes
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The Wittig reaction of a pool of stabilised ylides and aromatic aldehydes was carried out in a microwave oven. Only a few minutes were needed for high conversion rates under microwave heating in comparison to hour time with traditional methods.
- Frattini, Sara,Quai, Monica,Cereda, Enzo
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p. 6827 - 6829
(2007/10/03)
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- Studies on the Constituents of the Seeds of Hernandia ovigera L. VII. Syntheses of (+/-)-Hernolactone and (+/-)-Hernandin
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Two new lignans, hernolactone (1) and hernandin (2), isolated from the seeds of Hernandia ovigera L. were synthesized in racemic forms.Firstly, (+/-)-1 was obtained by utilizing the conjugate addition reaction of 4 with butenolide followed by alkylation with trimethoxybenzyl bromide and subsequent removal of the protecting groups.Synthesis of 2 was pursued using the corresponding 4-phenyl-1,2-dihydronaphthalene lactone (18).The cleavage of the lactone moiety of 18 afforded an unsaturated hydroxy acid (22).Subsequent hydrogenation of 22 followed by acidification with concentrated hydrochloric acid gave isopicrohernandin (21), leaving the 2,3-trans, 3,4-cis hydroxy acid (23), which was lactonized by means of N,N-dicyclohexylcarbodiimide to afford (+/-)-2.Keywords: Hernandia ovigera; hernolactone; hernandin; lignan; dibenzylbutyrolactone lignan; phenyltetralin lignan; isopicrohernandin; Diels-Alder reaction
- Tanoguchi, Mariko,Kashima, Tatsuhiko,Saika, Hideyuki,Inoue, Taishi,Arimoto, Masao,Yamaguchi, Hideo
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- LA REACTION DE WITTIG-HORNER EN MILIEU HETEROGENE VI. SELECTIVITE DE LA REACTION SUR DES COMPOSES BIFONCTIONNELS
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Heterogenous media of low basicity (K2CO3 or KHCO3), liquid-liquid or solid-liquid allow the Wittig-Horner reaction of fragile and unprotected aldehydes (hydroxyaldehydes, nitroaldehyde and ketoaldehydes) with excellent yields.The reaction is applied to the synthesis of Royal Jelly acid and Queen Substance of Honey bee.
- Villieras, Jean,Rambaud, Monique,Graff, Micheline
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- THE PALLADIUM-CATALYSED ARYLATION OF ACTIVATED ALKENES WITH AROYL CHLORIDES
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Aroyl chlorides react with activated alkenes in presence of a tertiary amine and a catalytic amount of palladium acetate to give arylated alkenes, specifically cinnamic acid derivatives and stilbenes.The reaction involves a highly efficient decarbonylation of the aroyl chloride.High yields can be obtained at low catalyst concentration by choice of an appropriate base.The reaction is not particularly sensitive to substituents in the aroyl chloride, although strongly electron-donating groups are advantagenous (yields up to 98percent).With monosubstituted alkenes E-isomers are formed with almost complete specificity.A mechanism for the reaction is proposed.
- Blaser, Hans-Ulrich,Spencer, Alwyn
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p. 267 - 274
(2007/10/02)
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