- Synthesis of cinnamic acid derivatives using ethanol as solvent or microwave assisted method
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A comparison study about some parameters which influence the condensation of veratraldehyde with malonic acid in the presence of piperidine using ethanol as solvent and microwave irradiation was done, the obtainment of several substituted cinnamic acids are reported.
- Pellon,Mamposo,Gonzalez,Calderon
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Read Online
- Photo-Promoted Decarboxylative Alkylation of α, β-Unsaturated Carboxylic Acids with ICH2CN for the Synthesis of β, γ-Unsaturated Nitriles
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An efficient, catalyst/photocatalyst-free, and cost-effective methodology for the decarboxylative alkylation of α,β-unsaturated carboxylic acids to synthesize β,γ-unsaturated nitriles has been developed. The reaction proceeded in an environmentally benign atmosphere of blue light-emitting diode irradiation with K2CO3 and water at room temperature. The methodology worked for a wide range of substrates (22 examples) with up to 83% yield. The protocol is also compatible for gram-scale synthesis.
- Pan, Chunxiang,Yang, Chunhui,Li, Kangkui,Zhang, Keyang,Zhu, Yuanbin,Wu, Shiyuan,Zhou, Yongyun,Fan, Baomin
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supporting information
p. 7188 - 7193
(2021/10/01)
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- Larvicidal activity and in silico studies of cinnamic acid derivatives against Aedes aegypti (Diptera: Culicidae)
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Cinnamic acid derivatives (CAD's) represent a great alternative in the search for insecticides against Aedes aegypti mosquitoes since they have antimicrobial and insecticide properties. Ae. aegypti is responsible for transmitting Dengue, Chikungunya, and Zika viruses, among other arboviruses associated with morbimortality, especially in developing countries. In view of this, in vitro analyses of n-substituted cinnamic acids and esters were performed upon 4th instar larvae (L4) of Ae. aegypti, as well as, molecular docking studies to propose a potential biological target towards this mosquitoes species. The larvicide assays proved that n-substituted ethyl cinnamates showed a more pronounced activity than their corresponding acids, in which p-chlorocinnamate (3j) presented a LC50 value of 8.3 μg/mL. Thusly, external morphologic alterations (rigid and elongated body, curved bowel, and translucent or darkened anal papillae) of mosquitoes’ group exposed to compound 3j, were observed by microscopy. In addition, an analytical method was developed for the quantification of the most promising analog by using high-performance liquid chromatography with UV detection (HPLC-UV). Molecular docking studies suggested that the larvicide action is associated with inhibition of acetylcholinesterase (AChE) enzyme. Therefore, expanding the larvicidal study with the cinnamic acid derivatives against the vector Ae. aegypti is important for finding search for more effective larvicides and with lower toxicity, since they have already shown good larvicidal properties against Ae. aegypti.
- Bezerra Fran?a, Saraliny,Carine Barros de Lima, Luana,Rychard da Silva Cunha, Cristhyan,Santos Anuncia??o, Daniela,Ferreira da Silva-Júnior, Edeildo,Ester de Sá Barreto Barros, Maria,José da Paz Lima, Dimas
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- Cinnamoyl-memantine hybrids: Synthesis, X-ray crystallography and biological activities
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Herein, framework combinations of antioxidant substituted cinnamic acids and memantine (N-methyl-D-aspartate receptor antagonist) in a new multi-targeted chemical entity were described. The amide bond formation of the memantine hybrids 1–5 was performed by EDC/HOBt coupling reaction. The chemical structures of the synthesized compounds were confirmed by means of melting points, UV, IR, 1H NMR, 13C NMR, and HRMS. Additionally, the crystal structures of memantine hybrids (2–5) were also studied by single-crystal X-ray diffraction. The single-crystal X-ray analysis revealed that the compounds 2, 5 crystallize in a centrosymmetric manner both in monoclinic space group (SG) P21/c, (No 14) and in a non-centrosymmetric manner for compounds 3 and 4, SG R3, (No 146) and SG P212121, (No 19), respectively. Furthermore, preliminary in vitro screenings of their neuroprotective and radical scavenging activities were performed. The radical scavenging activity of synthesized memantine hybrids was measured against 1,1-diphenyl-2-picrylhydrazyl (DPPH●), hydroxyl (OH●) and superoxide (O2●?) radicals and compared with the standard antioxidants (ferulic and sinapic acids). Radical scavenging activity studies show that amongst the tested hybrids, N-sinapoyl amide of memantine (3) emerges as the most potent antioxidant in all tests. Moreover, in vitro evaluation of anti-Alzheimer effects showed that the obtained memantine hybrids displayed neuroprotection in the moderate levels. Generally, they possess a little weaker activity as compared to the positive control memantine. Taken together, our findings reveal that the N-sinapoylamide of memantine (3) can be considered as a promising neuroprotective agent for Alzheimer's disease, acting as well as a potent radical scavenger.
- Chochkova, Maya,Jiang, Hailun,Kyoseva, Radoslava,Stoykova, Boyka,Tsvetanova, Elina,Alexandrova, Albena,Liu, Rui,Li, Zhuorong,Mitrev, Yavor,Dimitrova-Sbirkova, Hristina,?tícha, Martin,Shivachev, Boris
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- Photocatalytic decarboxylative alkenylation of α-amino and α-hydroxy acid-derived redox active esters by NaI/PPh3 catalysis
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Herein, we report the photocatalytic decarboxylative alkenylation reactions of N-(acyloxy)phthalimide derived from α-amino and α-hydroxy acids with 1,1-diarylethene, and with cinnamic acid derivatives through double decarboxylation, using sodium iodide and triphenylphosphine as redox catalysts. The reaction proceeds under mild irradiation conditions with visible blue light (440 nm or 456 nm) in an acetone solvent without recourse to transition-metal or organic dye based photoredox catalysts. The reaction proceeds via photoactivation of a transiently self-assembled chromophore from N-(acyloxy)phthalimide and NaI/PPh3. Solvation plays a crucial role in the reactivity.
- Fu, Ming-Chen,Fu, Yao,Shang, Rui,Wang, Ya-Ting,Zhao, Bin
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supporting information
p. 2495 - 2498
(2020/03/06)
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- Toward a Scalable Synthesis and Process for EMA401, Part II: Development and Scale-Up of a Pyridine- A nd Piperidine-Free Knoevenagel-Doebner Condensation
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During route scouting for EMA401 (1), an angiotensin II type 2 antagonist, we identified the synthesis of key amino acid intermediate 2 via its cinnamic acid derivative 3 as a streamlined option. In general, cinnamic acids can be synthesized from the corresponding aldehydes by a Knoevenagel-Doebner condensation in pyridine with piperidine as an organocatalyst. We aimed to replace both of these reagents and found novel conditions involving toluene as the solvent and morpholine as the organocatalyst. Scale-up of the process allowed the production of 25 kg of cinnamic acid 3 that was of the quality required for process development of the subsequent phenylalanine ammonia lyase-catalyzed step. The modified conditions were found to be widely applicable to alternative aldehydes and thus are of relevance to practitioners of chemical scale-up.
- Hardegger, Leo A.,Humair, Roger,Sidler, Eric
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p. 1756 - 1762
(2020/10/26)
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- Pd-Catalyzed decarboxylative cross-coupling reactions of epoxides with α,β-unsaturated carboxylic acids
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A Pd-catalyzed decarboxylative cross-coupling of α,β-unsaturated carboxylic acids with cyclic and acyclic epoxides has been developed. Both β-monosubstituted and β-disubstituted unsaturated carboxylic acids, as well as conjugated diene unsaturated carboxylic acids are suitable reaction substrates. Substituted homoallylic alcohols were obtained in moderate to good yields. The product was obtained as a mixture of diastereomers favoring the anti diastereomer of the cyclic epoxides. This work provides a method for the modification of complex organic molecules containing α,β-unsaturated carboxylic acids.
- Lu, Xiao-Yu,Li, Jin-Song,Wang, Shi-Qun,Zhu, Yu-Jing,Li, Yue-Ming,Yan, Lu-Yu,Li, Jia-Mei,Wang, Jin-Yu,Zhou, Hai-Pin,Ge, Xiu-Tao
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supporting information
p. 11123 - 11126
(2019/09/20)
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- Substituted cinnamic anhydrides act as selective inhibitors of acetylcholinesterase
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Cinnamic anhydrides have been shown to be more than reactive reagents, but they also act as inhibitors of the enzyme acetylcholinesterease (AChE). Thus, out of a set of 33 synthesised derivatives, several of them were mixed type inhibitors for AChE (from electric eel). Thus, (E)-3-(2,4-dimethoxyphenyl)acrylic anhydride (2c) showed Ki = 8.30 ± 0.94 μM and Ki′ = 9.54 ± 0.38 μM, and for (E)-3-(3-chlorophenyl)acrylic anhydride (2u) Ki = 8.23 ± 0.93 μM and Ki′ = 13.07 ± 0.46 μM were measured. While being not cytotoxic to many human cell lines, these compounds showed an unprecedented and noteworthy inhibitory effect for AChE but not for butyrylcholinesterase (BChE).
- Gie?el, Josephine M.,Serbian, Immo,Loesche, Anne,Csuk, René
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- METHOD FOR THE SYNTHESIS AND PRODUCTION OF ALKENYL COMPOUND
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PROBLEM TO BE SOLVED: To provide a method for producing an efficient alkenyl compound conveniently and inexpensively. SOLUTION: A first compound represented by formula (1) reacts with a second compound represented by formula (3), in the presence of amino acid, in solvent containing amine, in a range of 50-200°C, to produce an alkenyl compound represented by formula (A) [where R1 is hydrogen or an optionally substituted C1-C30 alkyl group, R2 is a carboxyl group or the like, R3 and R4 are hydrogen, an optionally substituted C1-C30 alkyl group or the like]. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0081; 0082
(2018/09/20)
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- Lithium perchlorate catalyzed electrophilic activation: A convenient one-pot synthesis of trans-cinnamic acids
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Background: Currently perchlorate catalysts gain much attention in organic synthesis due to ease of operation, wide applicability, high yield, and economy. This is evident through increasing number of citation related to their application in industry as well as other allied fields. The aim of this paper is to describe a methodology using lithium perchlorate to catalyze the Knoevenagel condensation reaction for the synthesis of biologically active trans-cinnamic acid in good to excellent yield. Methods: We discuss herein an economic, user-friendly one-pot synthesis of trans-cinnamic acids by refluxing a mixture of a malonic acid with aryl aldehyde in pyridine. The product was easily isolated via filtration and thereafter washed and characterized by spectroscopic methods. Results: This method is robust, stereoselective and high yielding. It can be utilized to synthesize a wide array of trans-cinnamic acids in good to excellent yield using 20% of lithium perchlorate catalyst. It is also useful in the synthesis of aliphatic α,β-unsaturated carboxylic acid. Conclusion: The role of lithium perchlorate as a mild catalyst in the synthesis of trans-cinnamic acid was explored. The reactions afforded a good yield of various products with simpler isolation.
- Kaur, Paranjeet,Khatik, Gopal L.
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p. 688 - 692
(2018/07/13)
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- Photoinduced, Copper-Promoted Regio- and Stereoselective Decarboxylative Alkylation of α,β-Unsaturated Acids with Alkyl Iodides
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The first example of UV light-induced, copper-catalyzed regio- and stereoselective decarboxylative coupling of α,β-unsaturated acids with alkyl iodides was reported. Under standard conditions, the 1°, 2°, and 3° alkyl iodides proceeded smoothly with the E-selective alkenes obtained in uniformly good yields and high stereoselectivities.
- Wang, Chao,Lei, Yingjie,Guo, Mengzhun,Shang, Qinyu,Liu, Hong,Xu, Zhaoqing,Wang, Rui
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p. 6412 - 6415
(2017/12/08)
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- Direct comparison of the enzymatic characteristics and superoxide production of the four aldehyde oxidase enzymes present in mouse
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Aldehyde oxidases (AOXs) are molybdoflavoenzymes with an important role in the metabolism and detoxification of heterocyclic compounds and aliphatic as well as aromatic aldehydes. The enzymes use oxygen as the terminal electron acceptor and produce reduced oxygen species during turnover. Four different enzymes, mAOX1, mAOX3, mAOX4, and mAOX2, which are the products of distinct genes, are present in the mouse. A direct and simultaneous comparison of the enzymatic properties and characteristics of the four enzymes has never been performed. In this report, the four catalytically active mAOX enzymes were purified after heterologous expression in Escherichia coli. The kinetic parameters of the four mouse AOX enzymes were determined and compared with the use of six predicted substrates of physiologic and toxicological interest, i.e., retinaldehyde, N1-methylnicotinamide, pyridoxal, vanillin, 4-(dimethylamino)cinnamaldehyde (p-DMAC), and salicylaldehyde. While retinaldehyde, vanillin, p-DMAC, and salycilaldehyde are efficient substrates for the four mouse AOX enzymes, N1-methylnicotinamide is not a substrate of mAOX1 or mAOX4, and pyridoxal is not metabolized by any of the purified enzymes. Overall, mAOX1, mAOX2, mAOX3, and mAOX4 are characterized by significantly different KM and kcat values for the active substrates. The four mouse AOXs are also characterized by quantitative differences in their ability to produce superoxide radicals. With respect to this last point, mAOX2 is the enzyme generating the largest rate of superoxide radicals of around 40% in relation to moles of substrate converted, and mAOX1, the homolog to the human enzyme, produces a rate of approximately 30% of superoxide radicals with the same substrate.
- Kücükg?ze, G?khan,Terao, Mineko,Garattini, Enrico,Leimkühler, Silke
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p. 947 - 955
(2017/07/22)
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- Triethylamine: A potential N-base surrogate for pyridine in Knoevenagel condensation of aromatic aldehydes and malonic acid
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Cinnamic acids are intermediates with significant potential for synthesis of several industrially important chemicals. Classically, cinnamic acids are produced through Knoevenagel condensation of aromatic aldehydes and malonic acid in the presence of an organocatalyst and large amounts of carcinogenic pyridine. An alternative pyridine free reaction scheme for Knoevenagel condensation of malonic acid and aromatic aldehydes was investigated by replacing pyridine with an aliphatic tertiary amine surrogate in toluene as the reaction medium. Of the three aliphatic tertiary amines used, namely, triethyl amine (TEA), trioctyl amine (TOA) and tributyl amine (TBA), only TEA afforded cinnamic acids in comparable yields to those obtained with pyridine. Validation through a computational analysis is attempted to provide an explanation for the observed role of TEA as an aliphatic N-base instead of TBA and TOA. The use of TEA as a mild base in place of pyridine can be seen as playing the dual role of a base catalyst as well as a phase transfer agent evidenced by the in-process ATR-FITR spectroscopy. Use of the TEA-toluene system in place of pyridine can be seen as resulting in a process that affords ease of handling, separation and recycling of the solvent and the catalyst.
- Pawar, Hitesh S.,Wagh, Adhirath S.,Lali, Arvind M.
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p. 4962 - 4968
(2016/07/06)
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- Synthesis and biological evaluation of (E)-cinnamic acid, (E)-2-styrylthiazole and (E)-2-[2-(naphthalen-1-yl)vinyl]thiazole derivatives
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Cinnamyl- and thiazole-based compounds have been shown to exhibit diverse medicinal properties and a series of twelve (E)-2-styrylthiazole and (E)-2-[(naphthalen-1-yl)vinyl]thiazole derivatives, which are conjugates of both systems and which satisfy the "Lipinski rule of 5", have been synthesised and subjected to in vitro biological screening. While insignificant inhibition (60-98% viability at 10 μM) of HeLa (cervical cancer) cells was noted, all five of the (E)-2-[naphthalen-1- yl)vinyl]thiazole derivatives proved remarkably active against SH-SY5Y (neuroblastoma) cells with IC50 values ranging from 2.09 to 8.64 μM. Two of the seven (E)-2-styrylthiazoles were found to be moderately active (with IC50 values of 10.8 and 11.7 mM), whereas the remaining five analogues exhibit significant proliferation of SH-SY5Y cells (with IC50 values of 180-1000 mM). The results warrant further studies on the effects of styrylthiazoles on the differentiation and extension of SH-SY5Y cells in order to assess their activity in neurological degenerative diseases.
- Olawode, Emmanuel O.,Tandlich, Roman,Prinsloo, Earl,Isaacs, Michelle,Hoppe, Heinrich,Seldon, Ronnett,Warner, Digby F.,Steenkamp, Vanessa,Kaye, Perry T.
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p. 284 - 296
(2018/03/09)
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- Synthesis and biological evaluation of (E)-cinnamic acid, (E)-2-styrylthiazole and (E)-2-[2-(naphthalen-1-yl)vinyl]thiazole derivatives
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Cinnamyl- and thiazole-based compounds have been shown to exhibit diverse medicinal properties and a series of twelve (E)-2-styrylthiazole and (E)-2-[(naphthalen-1-yl)vinyl]thiazole derivatives, which are conjugates of both systems and which satisfy the “Lipinski rule of 5”, have been synthesised and subjected to in vitro biological screening. While insignificant inhibition (60-98% viability at 10 μM) of HeLa (cervical cancer) cells was noted, all five of the (E)-2-[naphthalen-1-yl)vinyl]thiazole derivatives proved remarkably active against SH-SY5Y (neuroblastoma) cells with IC50 values ranging from 2.09 to 8.64 μM. Two of the seven (E)-2-styrylthiazoles were found to be moderately active (with IC50 values of 10.8 and 11.7 mM), whereas the remaining five analogues exhibit significant proliferation of SH-SY5Y cells (with IC50 values of 180-1000 mM). The results warrant further studies on the effects of styrylthiazoles on the differentiation and extension of SH-SY5Y cells in order to assess their activity in neurological degenerative diseases.
- Olawode, Emmanuel O.,Tandlich, Roman,Prinsloo, Earl,Isaacs, Michelle,Hoppe, Heinrich,Seldon, Ronnett,Warner, Digby F.,Steenkamp, Vanessa,Kaye, Perry T.
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p. 284 - 296
(2018/05/09)
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- Synthesis and biological evaluation of N-cinnamoyl and mandelate metformin analogues
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A series of N,N-dimethyl-N1-[3-(substituted phenyl)-1-oxo-2-propenyl]biguanides were synthesized by coupling a solution of metformin in pyridine with different cinnamoyl chloride derivatives in ether for 3 h in addition to synthesis of some five molecules of metformin-mandelates. All the synthesized cinnamoyl metformins and a few metformin-mandelates were characterized by IR, NMR and Mass spectroscopic techniques. All the synthesized compounds were also evaluated for their antioxidant activity by DPPH scavenging method and nitric oxide scavenging method. All the compounds exhibited good antioxidant activity.
- Anitha Kumari,Bharathi,Prabhu,Ponnudurai
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p. 1895 - 1898
(2016/07/06)
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- Design, synthesis and cytotoxic evaluation of novel imatinib amide derivatives that target Abl kinase
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Novel imatinib amide derivatives (a1-28, b1-9) were synthesized and evaluated for their biological activities. All compounds were characterized by 1H NMR, MS and elemental analysis. Among all the derivatives, compounds a4, a10, a21, b1 and b2 displayed the most significant ability of inhibiting K562 cell proliferation with the IC50 values of 0.67, 0.66, 0.65, 0.59 and 0.62 μM, respectively, indicating that these compounds were potent inhibitors of Bcr-Abl in leukemic K562 cells, comparable to the reference compound imatinib. Molecular docking study was performed to position compounds a21 and b1 into the active site of Abl to determine the probable binding modes
- Yao, Ri-Sheng,Guan, Qiu-Xiang,Lu, Xiao-Qin,Ruan, Ban-Feng
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- Nucleophile-selective cross-coupling reactions with vinyl and alkynyl bromides on a dinucleophilic aromatic substrate
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A nucleophile-selective cross-coupling reaction on an aromatic compound bearing two metal groups, Bpin and SnMe3, has been developed. Previously, only aryl bromides and iodides could be used as electrophilic components, but in this work, the scope could be extended to vinyl and alkynyl bromides as electrophiles. This means that the roles typical in Sonogashira couplings or Heck reactions of the aromatic ring as the dielectrophile coupling to vinyl and alkynyl metal species are reversed, which presents a new tool for organic synthesis. The first nucleophilic site to react is the stannyl group, and subsequently, a Suzuki-Miyaura cross-coupling reaction can take place on the same molecule.
- He, Lu-Ying,Schulz-Senft, Mathias,Thiedemann, Birk,Linshoeft, Julian,Gates, Paul J.,Staubitz, Anne
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supporting information
p. 2498 - 2502
(2015/04/22)
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- Solvent-dependent regioselective oxidation of trans-chalcones using aqueous hydrogen peroxide
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A novel method for regioselective oxidation of trans-chalcones with hydrogen peroxide in acetonitrile to afford cinnamic acids is reported. Only trans-β-arylacrylic acids were observed. A wide range of functionalized products can be effectively produced from various chalcones in good to excellent yields.
- Wang, Peng,Cai, Jin,Yang, Jiabin,Sun, Chunlong,Li, Lushen,Ji, Min
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p. 518 - 522
(2013/08/25)
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- Synthesis, molecular modeling and biological evaluation of β-ketoacyl-acyl carrier protein synthase III (FabH) as novel antibacterial agents
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A series of novel cinnamic acid secnidazole ester derivatives have been designed and synthesized, and their biological activities were also evaluated as potential inhibitors of FabH. These compounds were assayed for antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus. Compounds with potent antibacterial activities were tested for their E. coli FabH inhibitory activity. Compound 3n showed the most potent antibacterial activity with MIC of 1.56-6.25 μg/mL against the tested bacterial strains and exhibited the most potent E. coli FabH inhibitory activity with IC50 of 2.5 μM. Docking simulation was performed to position compound 3n into the E. coli FabH active site to determine the probable binding conformation.
- Zhang, Hong-Jia,Zhu, Di-Di,Li, Zi-Lin,Sun, Juan,Zhu, Hai-Liang
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experimental part
p. 4513 - 4519
(2011/09/12)
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- Synthesis, biological evaluation, and molecular modeling of cinnamic acyl sulfonamide derivatives as novel antitubulin agents
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A series of novel cinnamic acyl sulfonamide derivatives (9a-16e) have been designed and synthesized and their biological activities were also evaluated as potential tubulin polymerization inhibitors. Among all the compounds, 10c showed the most potent growth inhibitory activity against B16-F10 cancer cell line in vitro, with an IC50 value of 0.8 μg/mL. Docking simulation was performed to insert compound 10c into the crystal structure of tubulin at colchicine binding site to determine the probable binding model. Based on the preliminary results, compound 10c with potent inhibitory activity in tumor growth may be a potential anticancer agent.
- Luo, Yin,Qiu, Ke-Ming,Lu, Xiang,Liu, Kai,Fu, Jie,Zhu, Hai-Liang
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experimental part
p. 4730 - 4738
(2011/09/20)
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- Development of tryptase inhibitors derived from thalidomide
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A novel series of tryptase inhibitors with a N-phenylphthalimide skeleton structurally derived from thalidomide (1) has been developed. Structure-activity relationship studies led to a potent and selective tryptase inhibitor, 2-(4-cyanophenyl)isoindole-1,3-dione-5-yl 3-(2-aminopyridin-5-yl)propanoate (7), with the IC50 value of 78 nM.
- Tetsuhashi, Masashi,Ishikawa, Minoru,Hashimoto, Mariko,Hashimoto, Yuichi,Aoyama, Hiroshi
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experimental part
p. 5323 - 5338
(2010/09/15)
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- Bismuth(III) chloride-mediated, efficient, solvent-free, mwi-enhanced doebner condensation for the synthesis of (E)-cinnamic acids
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A bismuth(III) chloride-mediated green process for the production of (E)-cinnamic acid derivatives using microwave irradiation under solvent-free conditions is described. The (E)-cinnamic acids are obtained in excellent yields. This protocol is green because it employs an established environmentally benign procedure, microwave irradiation. Solvent vapor pollution is not there because it is solvent free, and bismuth(III) chloride is an established nontoxic catalyst. Copyright
- Suresh,Kumar, Dhruva,Sandhu, Jagir S.
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experimental part
p. 1915 - 1919
(2010/09/14)
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- Polymer-assisted solution-phase synthesis under combined ultrasound and microwave irradiation: Preparation of α,β-unsaturated esters and carboxylic acids, key intermediates of novel sigma ligands
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The optimal conditions to prepare α,β-unsaturated methyl esters via Wittig reaction combining polymer-assisted solution-phase synthesis (PASPS) methodology and simultaneous ultrasound and microwave irradiation were established. The effects of temperature, solvent, and irradiation time were discussed. Results clearly indicated the superiority of combined ultrasound and microwave-assisted procedure over microwave-assisted methodology. Moreover, an efficient PASPS procedure to prepare α,β-unsaturated carboxylic acids via tandem Wittig olefination and hydrolysis reaction was developed under combined ultrasound and microwave irradiation. Generally, a good conversion of aldehydes to acids was observed. The optimized protocols allowed us to quickly prepare a small collection of either α,β-unsaturated esters or carboxylic acids, key intermediates for the drug-discovery process of new sigma ligands. Copyright Taylor & Francis Group, LLC.
- Rossi,Urbano,Baraglia, A. Carnevale,Serra,Bergamelli,Iannelli,Azzolina,Collina
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p. 3254 - 3262
(2011/03/18)
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- Pathways for the solvent-free condensation between schiff bases and methylenic compounds
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Pathways for the solvent-free condensation between Schiff Bases and methylenic compounds are discussed taking into account the reported mechanistic purposes and new experimental data.
- Razus, Alexandra C.,Nitu, Carmen,Tecuceanu, Victorita,Birzan, Liviu
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p. 729 - 736
(2007/10/03)
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- Competitive formation of β-amino acids, propenoic, and ylidenemalonic acids by the Rodionov reaction from malonic acid, aldehydes, and ammonium acetate in alcoholic medium
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The Rodionov reaction of 49 available aliphatic and aromatic aldehydes with malonic acid and ammonium acetate in alcoholic medium, resulting in formation of β-amino acids, propenoic, and ylidenemalonic acids, was studied. Certain regioselectivity regularities of the reaction were revealed. Among the variety of ketones studied, cyclohexanone is the only whose reaction yields a β-amino acid. Unusual dehydrofluorination of 6-chloro-2-fluorocinnamic acid under the Rodionov reaction was discovered. 2005 Pleiades Publishing, Inc.
- Lebedev,Lebedeva,Sheludyakov,Kovaleva,Ustinova,Kozhevnikov
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p. 1113 - 1124
(2007/10/03)
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- KOH-promoted reaction of C,O,O-tris(trimethylsilyl) ketene acetal with aldehydes: Practical and easy access to (E)-α,β-ethylenic carboxylic acids
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The use of a catalytic amount of KOH has been found to be very efficient in promoting reaction of silylketene acetal 1 with aldehydes 2 to afford the corresponding (E)-α,β-ethylenic carboxylic acids 3 under very mild conditions.
- Lensen,Mouelhi,Bellassoued
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p. 1007 - 1011
(2007/10/03)
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- Solvent-free oxidations of alcohols, oximes, aldehydes and cyclic acetals by pyridinium chlorochromate
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Oxidative transformations of alcohols, oximes and cyclic acetals to carbonyl compounds proceed efficiently by pyridinium chlorochromate (PCC) under solvent-free conditions. The oxidation of aromatic and cinnamylic aldehydes to carboxylic acids, which does not occur by PCC in solution, is achieved satisfactorily in the absence of solvent.
- Salehi,Firouzabadi,Farrokhi,Gholizadeh
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p. 2273 - 2276
(2007/10/03)
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- Synthesis of cinnamic acids catalyzed by expansive graphite under ultrasound
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Knoevenagel condensation of malonic acid with aromatic aldehydes catalysed by expansive graphite results cinnamic acids in 65-98% yields under ultrasound irradiation.
- Li,Zang,Feng,Li,Li
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p. 653 - 656
(2007/10/03)
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- Substituent Effects in the Reaction of t-Butylmagnesium Chloride with Substituted Ethyl Cinnamates. A Correlation with 13C NMR Chemical Shifts
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The reaction of t-butylmagnesium chloride with some substituted ethyl (E)-cinnamates gave mainly 1,3-, 1,4-, 1,2- and 1,4-addition products and minor amounts of 1,2- and 1,3-addition products.The relative amounts of 1,3-addition products has been shown to correlate with 13C NMR chemical shifts of C-α of the ethyl cinnamates.The correlation indicates that the regio selectivity of the reactions is to a great extent dependent of polar effects and that the t-butyl radical has a nucleophilic character.
- Jalander, Lars
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p. 419 - 428
(2007/10/02)
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