- Photocatalytic acyl azolium-promoted alkoxycarbonylation of trifluoroborates
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Despite recent advancements in the selective generation and coupling of organic radical species, the alkoxycarbonyl radical remains underexplored relative to other carbon-containing radical species. Drawing inspiration from new strategies for generating acyl radical equivalents utilizing dual N-heterocyclic carbene catalysis and photocatalysis, we have prepared dimethylimidazolium esters that can function as an alkoxycarbonyl radical surrogate under photocatalytic conditions. We demonstrate the synthetic utility of these azolium-based partners through the preparation of esters arising from the coupling of this radical surrogate with an oxidatively generated alkyl radical.
- Scheidt, Karl A.,Zhu, Joshua L.
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- Chemoenzymatic synthesis and antileukemic activity of novel C9- and C14-functionalized parthenolide analogs
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Parthenolide is a naturally occurring terpene with promising anticancer properties, particularly in the context of acute myeloid leukemia (AML). Optimization of this natural product has been challenged by limited opportunities for the late-stage functionalization of this molecule without affecting the pharmacologically important α-methylene-γ-lactone moiety. Here, we report the further development and application of a chemoenzymatic strategy to afford a series of new analogs of parthenolide functionalized at the aliphatic positions C9 and C14. Several of these compounds were determined to be able to kill leukemia cells and patient-derived primary AML specimens with improved activity compared to parthenolide, exhibiting LC50values in the low micromolar range. These studies demonstrate that different O–H functionalization chemistries can be applied to elaborate the parthenolide scaffold and that modifications at the C9 or C14 position can effectively enhance the antileukemic properties of this natural product. The C9-functionalized analogs 22a and 25b were identified as the most interesting compounds in terms of antileukemic potency and selectivity toward AML versus healthy blood cells.
- Tyagi, Vikas,Alwaseem, Hanan,O'Dwyer, Kristen M.,Ponder, Jessica,Li, Qi Ying,Jordan, Craig T.,Fasan, Rudi
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- TRANSITION METAL COMPLEX CATALYZED CARBONYLATION OF ORGANIC HALIDES IN THE PRESENCE OF MOLECULAR SIEVES INSTEAD OF BASE
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In the presence of molecular sieves under base free conditions organic halides are successfully carbonylated under carbon monoxide pressure with water or alcohols catalyzed by Co or Pd complex to generate the corresponding carboxylic acids or esters, respectively, in good yields.
- Urata, Hisao,Hu, Nan-Xing,Maekawa, Hisayuki,Fuchikami, Takamasa
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- Trimethylamine N-oxide: A novel reagent for the promotion of the retro- aldol reaction of R106-1 (LY295337)
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The retro-aldol reaction of R106-1 (LY295337), 1 using trimethylamine N- oxide (TNO) facilitates the removal of the tertiary hydroxy group generating R106-sarcosine, 2 a key synthetic intermediate. The reagent is highly reproducible and provides high yields with no major side products. A side by side comparison of TNO vs. traditional bases is described.
- Rodriguez,Zweifel
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- S,S'-Bis(1-phenyl-1H-tetrazol-5-yl) Dithiocarbonate: A New Esterification Reagent
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S,S'-Bis(1-phenyl-1H-tetrazol-5-yl) dithiocarbonate is a useful reagent for the esterification of carboxylic acids with alcohols, including lactonization.The reagent is conveniently prepared in good yield from 1-phenyl-5-thioxo-4,5-dihydro-1H-tetrazole and trichloromethyl chloroformate (trichloromethyl carbonochloridate) in ethyl acetate in the presence of triethylamine.Its structure was confirmed by (13)C-NMR spectrometry and single-crystal X-ray analysis.
- Takeda, Kazuyoshi,Tsuboyama, Kanoko,Takayanagi, Hiroaki,Ogura, Haruo
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- Radical aromatic substitution via atom-transfer addition
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New methodology for radical aromatic substitution has been developed involving the addition of electron-deficient radicals to unprotected pyrroles and indole. This non-oxidative process is presumed to be occurring via atom- transfer addition of suitable organoiodides and bromides with subsequent non- radical elimination of HI or HBr, respectively. The process also occurs under stannane-free conditions.
- Byers, Jeffrey H.,Campbell, John E.,Knapp, Faith H.,Thissell, Jameson G.
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- Structure activity relationship of organic alcohol and esters for antidepressant-like activity
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The synthesized compounds 1-7 were evaluated for their antidepressant activity, among which 2-phenylethyl alcohol 1 and isoamyl phenylacetate 3 showed 43 % and 37 % reduction in immobility time in mice using forced swim test, thereby, displaying antidepressant-like activity. Compound 1 and 3 were equipotent and both these compounds were 2x effective than the standard drug phenelzine. Considering other esters it appears that a decrease in alkyl chain length or addition of either NO2 or OH groups to the phenyl ring caused a marked decline in the antidepressant-like activity.
- Perveen, Shahnaz,Yasmeen, Arfa,Khan, Muhammad Aitmaud,Dar, Ahsana,Jafri, Rehana,Ahmed, Amir
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- Pd-catalyzed synthesis of arylacetic acid derivatives from boronic acids
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A palladium(0)-catalyzed cross-coupling reaction between arylboronic acids or esters and α-bromoacetic acid derivatives is described which allows the synthesis of various functionalized arylacetic acid derivatives under mild conditions.
- Goossen
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- Metal-free hydroalkoxylation of ynesulfonamides with esters
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An efficient metal-free hydroalkoxylation reaction of ynesulfonamides with esters under mild conditions is described. Under the catalysis of TMSOTf, various ynesulfonamides are transformed into the corresponding alkoxy-substituted enamides in high yields
- Gao, Erhui,Peng, Cheng,Zhang, Jingyi,Wang, Xiao-Na,Chang, Junbiao
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- Synthesis, Structural Analysis, and Screening of Some Novel 5-Substituted Aryl/Aralkyl-1,3,4-Oxadiazol-2-Yl 4-(Morpholin-4-Ylsulfonyl)Benzyl Sulfides As Potential Antibacterial Agents
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A series of new 5-substituted aryl/aralkyl-1,3,4-oxadiazol-2-yl 4-(morpholin-4-ylsulfonyl)benzyl sulfides 6a-k were synthesized by converting multifarious aryl/aralkyl organic acids 1a-k successively into corresponding esters 2a-k, hydrazides 3a-k, and 5-substituted aryl/aralkyl-1,3,4-oxadiazole-2-thiols 4a-k. Finally, the target compounds, 6a-k were prepared by stirring 5-substituted-1,3,4-oxadiazole-2-thiols with 4-(4-(bromomethyl)phenylsulfonyl) morpholine (5) in the presence of N,N-dimethylformamide (DMF) and sodium hydride (NaH). The structures of the newly synthesized compounds were elucidated by spectroscopic techniques. In addition, the antibacterial activity of all the synthesized compounds was investigated in vitro against Gram-positive and Gram-negative bacteria by using ciprofloxacin as reference standard drug and the results showed that some of the tested compounds possessed good antibacterial activity.
- Aziz-Ur-Rehman,Gul, Samreen,Abbasi, Muhammad Athar,Nafeesa, Khadija,Akhtar, Muhammad Nadeem,Ahmad, Irshad,Afzal, Saira
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- Palladium-Catalyzed C(sp3)-C(sp2) Cross-Couplings of O -(α-Bromoacyl) Cyanohydrins with Boronic Acids: An Entry to Enantioenriched N -Acylated β-Amino Alcohols
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Suzuki-type cross-coupling of enantiomerically enriched O-(α-bromoacyl) cyanohydrins with aromatic boronic acids substituted with electron-withdrawing or electron-donating groups gave the expected coupling products in high yields without racemization. These substrates exhibit higher reactivities than analogous substrates lacking the nitrile function, probably as a result of π-coordination of the nitrile to palladium. Reduction of the nitrile group of the products, with accompanying intramolecular acyl transfer, provides access to biologically interesting N-acylated β-amino alcohols.
- Hertzberg, Robin,Dinér, Peter,Moberg, Christina
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- Water works: An efficient palladium-catalyzed cross-coupling reaction between boronic acids and bromoacetate with aminophosphine ligand
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Water greatly restrained the formation of self-coupling of boronic acids in a palladium-catalyzed cross-coupling reaction between boronic acids and ethyl bromoacetate with an aminophosphine ligand; good to excellent yields of cross-coupling product were obtained.
- Peng, Zhi-Yong,Wang, Jian-Ping,Cheng, Jiang,Xie, Xiao-Min,Zhang, Zhaoguo
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- Trans-esterification in dry media using ferric perchlorate adsorbed on silica gel
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Adsorption of Fe(ClO4)3(H2O)6 onto chromatographic grade silica gel in the presence of ethyl acetate (to be used for trans-esterification) produces a supported reagent, Fe(ClO4)3(EtOAc)6/SiO2. This reagent, has been found effective for the rapid and high yield of esters via trans- esterification on grinding in the presence of alcohols/carboxylic acids using pestle and mortar in the solid state.
- Parmar, Anupama,Goyal, Rita,Kumar, Baldev,Kumar, Harish
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- A novel aromatic carbocation-based coupling reagent for esterification and amidation reactions
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A novel tropylium-based coupling reagent has been developed to facilitate the synthesis of a series of esters, amides, lactones and peptides under mild reaction conditions. Remarkably, this reagent can be used in catalytic amounts in conjunction with a sacrificial reagent, offering a new and efficient method for nucleophilic coupling reactions of carboxylic acids.
- Nguyen, Thanh V.,Lyons, Demelza J.M.
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- Targeting malaria and leishmaniasis: Synthesis and pharmacological evaluation of novel pyrazole-1,3,4-oxadiazole hybrids. Part II
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In continuance with earlier reported work, an extension has been carried out by the same research group. Mulling over the ongoing condition of resistance to existing antimalarial agents, we had reported synthesis and antimalarial activity of certain pyrazole-1,3,4-oxadiazole hybrid compounds. Bearing previous results in mind, our research group ideated to design and synthesize some more derivatives with varied substitutions of acetophenone and hydrazide. Following this, derivatives 5a–r were synthesized and tested for antimalarial efficacy by schizont maturation inhibition assay. Further, depending on the literature support and results of our previous series, certain potent compounds (5f, 5n and 5r) were subjected to Falcipain-2 inhibitory assay. Results obtained for these particular compounds further strengthened our hypothesis. Here, in this series, compound 5f having unsubstituted acetophenone part and a furan moiety linked to oxadiazole ring emerged as the most potent compound and results were found to be comparable to that of the most potent compound (indole bearing) of previous series. Additionally, depending on the available literature, compounds (5a–r) were tested for their antileishmanial potential. Compounds 5a, 5c and 5r demonstrated dose-dependent killing of the promastigotes. Their IC50 values were found to be 33.3 ± 1.68, 40.1 ± 1.0 and 19.0 ± 1.47 μg/mL respectively. These compounds (5a, 5c and 5r) also had effects on amastigote infectivity with IC50 of 44.2 ± 2.72, 66.8 ± 2.05 and 73.1 ± 1.69 μg/mL respectively. Further target validation was done using molecular docking studies. Acute oral toxicity studies for most active compounds were also performed.
- Verma, Garima,Khan, Mohemmed Faraz,Mohan Nainwal, Lalit,Ishaq, Mohd,Akhter, Mymoona,Bakht, Afroz,Anwer, Tariq,Afrin, Farhat,Islamuddin, Mohammad,Husain, Ibraheem,Alam, Mohammad Mumtaz,Shaquiquzzaman, Mohammad
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- Selective transesterification of aliphatic acids in the presence of aromatic acids using silica gel supported NaHSO4 catalyst
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Acidolysis of EtOAc in the presence of silica gel supported NaHSO4 catalyst has been applied for the protection of aliphatic nonconjugated carboxylic acids through the formation of esters.
- Das,Venkataiah
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- Synthesis and anti-inflammatory activity of hydrazones bearing biphenyl moiety and vanillin based hybrids
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The intense research work in the field of medicinal chemistry has enhanced the significance of Biphenyl moiety as pharmacologically important compound. Some of the compounds bearing Biphenyl moiety possess important medicinal properties like antihypertensive and calcium channel blocker, anti-inflammatory, diuretic, anti-diabetic activity, antipsychotic and anxiolytic activity. The present article describes the synthesis of novel benzohydrazides and 2-phenylacetohydrazides bearing Biphenyl moiety and vanillin hybrid. The synthesized compounds (31-40) were characterized by 1H NMR, Mass and IR spectroscopic techniques and were evaluated for anti-inflammatory activity by carrageenan paw edema method. The results of the study revealed that compounds 39 and 40 (bearing 2-(4-nitrophenyl)acetohydrazide and 2-(2,3-dihydrobenzofuran-5-yl)acetohydrazide) showed maximum anti-inflammatory activity while the compounds 31, 32, 33, 34 and 38 bearing benzohydrazides displayed moderate anti-inflammatory activity.
- Kumar Reddy,Kathale, Niren E.
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- Synthesis and catalytic applications of 1,2,3-triazolylidene gold(i) complexes in silver-free oxazoline syntheses and C-H bond activation
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A series of novel 1,2,3-triazolylidene gold(i) chloride complexes have been synthesised and fully characterised. Silver-free methodologies for chloride ion abstraction of these complexes were evaluated for their potential as Au-based catalyst precursors. Using simple potassium salts or MeOTf as chloride scavengers produced metal complexes that catalyse both the regioselective synthesis of oxazolines and the C-H activation of benzene or styrene for carbene transfer from ethyl diazoacetate. These results indicate that Ag-free activation of 1,2,3-triazolylidene gold(i) chloride complexes is feasible for the generation of catalytically active Au triazolylidene species. However, silver-mediated activation imparts substantially higher catalytic activity in oxazoline synthesis.
- Pretorius, René,Fructos, Manuel R.,Müller-Bunz, Helge,Gossage, Robert A.,Pérez, Pedro J.,Albrecht, Martin
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- Selective synthesis of arylacetic acid esters from ethyl acetoacetate and aryl halides in the presence of copper(II) on 4 ? molecular sieves
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A heterogeneous catalyst, copper(II) on 4 ? molecular sieves has successfully been used in the arylation of ethyl acetoacetate, selectively forming arylacetic esters in high yields. The air stable and easily handled catalyst can be simply filtered off during purification thus avoiding significant metal contamination of the product.
- Zsolczai, Dávid,Németh, János,Hell, Zoltán
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- Synthesis and anti-inflammatory activity of hydrazide-hydrazones bearing anacardic acid and 1,2,3-triazole ring based hybrids
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A novel series of hydrazide-hydrazone derivatives 39-50, linked with anacardic acid motif and 1,2,3-triazole ring were synthesized by reacting 4-(1-(2-methoxy-6-pentadecylbenzyl)-1H-1, 2, 3-triazol-4-yl)benzaldehyde with 2-phenyl-acetohydrazides and benzohydrazides. The structures of the newly synthesized hydrazide-hydrazone derivatives 39-50 were confirmed by 1H NMR, MS and IR spectroscopic tools. These compounds were also evaluated for their anti-inflammatory activity by carrageenan paw edema method.
- Kumar Reddy,Kathale, Niren E
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- Palladium supported on triphenylphosphine functionalized porous organic polymer: A highly active and recyclable catalyst for alkoxycarbonylation of aryl iodides
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An efficient method for the alkoxycarbonylation of aryl iodides using palladium supported on triphenylphosphine functionalized porous organic polymer (Pd@KAPs(Ph-PPh3)) as the catalyst is reported. Under balloon pressure of CO, various aryl iodides on carbonylation with alcohols and phenols give the corresponding products in moderate to excellent yields (74-96%). The catalyst can be easily separated by simple filtration process and recycled up to ten times without significant decrease in activity. The salient features of this protocol are the simplicity in handling of the catalyst, low CO pressure, negligible palladium leaching and good catalyst recyclability.
- Lei, Yizhu,Wu, Linjuan,Zhang, Xuefeng,Mei, Hui,Gu, Yanlong,Li, Guangxing
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- Synthesis, antiproliferative activity, and molecular docking studies of curcumin analogues bearing pyrazole ring
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Several curcumin analogues bearing pyrazole were synthesized and characterized by IR, NMR, and mass spectral data. There were four tested compounds among 11 synthesized compounds, which were evaluated for antiproliferative activity and showed significant activity in both one-dose and five-dose assays. The antiproliferative effects were tested on a panel of 60 cell lines, according to the National Cancer Institute screening protocol. The most active compounds among the series were 3,5-bis(4-hydroxy-3-methylstyryl)-1H-pyrazole-1-carboxamide (3k) which showed mean percent growth inhibition of 116.09 in one-dose assay at 10 μM, and GI50 values were ranging between 0.0912 and 2.36 μM in five-dose assay. The best results were recorded on the leukaemia cell lines with value ranging from 0.0912 to 0.365 μM. All the tested compounds showed broad-spectrum antiproliferative activity over different cancer cell lines. When compared with the standard drug paclitaxel, the compound 3k showed superior activity on nearly 42 cell lines. The molecular docking study was performed to explore the binding interaction of these curcumin analogues with the active site of EGFR tyrosine kinase (EGFR-TK). The hydroxyl group of both phenyl rings was important for the rein-geminated hydrogen bonding by either side chain or backbone with the active site of EGFR-TK. Graphical Abstract: Four curcumin analogues were evaluated for their antiproliferative activity and showed promising results. The molecular docking studies showed that all the compounds (3a-k) were well accommodated in the EGFR tyrosine kinase.[Figure not available: see fulltext.]
- Ahsan, Mohamed Jawed,Choudhary, Kavita,Jadav, Surender Singh,Yasmin, Sabina,Ansari, Md. Yousuf,Sreenivasulu, Reddymasu
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- Oxadiazole mannich bases: Synthesis and antimycobacterial activity
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A series of oxadiazole mannich bases were synthesized by reacting oxadiazole derivatives, dapsone and appropriate aldehyde in the presence of methanol. The synthesized compounds were evaluated for antimycobacterial activity against M. tuberculosis H37Rv and INH resistant M. tuberculosis. Among the synthesized compounds, compound (4) 3-{2-furyl[4-(4-{2-furyl[5-(2-naphthyloxymethyl)-2-thioxo-2,3-dihydro-1,3,4-oxadiazol-3-yl]methylamino}phenylsulfonyl)anilino]methyl}-5-(2-naphthyloxymethyl)-2,3-dihydro-1,3,4-oxadiazole-2-thione was found to be the most promising compound active against M. tuberculosis H37Rv and isoniazid (INH) resistant M. tuberculosis with Minimum inhibitory concentration (MIC) 0.1 μM & 1.10 μM respectively.
- Ali, Mohamed Ashraf,Shaharyar, Mohammad
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- Preparative-scale enzyme-catalyzed synthesis of (R)-α-fluorophenylacetic acid
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A preparative-scale asymmetric synthesis of (R)-α-fluorophenylacetic acid, a useful chiral derivatizing reagent, is described. Starting from ethyl α-bromophenylacetate, α-fluorophenylmalonic acid dipotassium salt was prepared in three steps (54% yield), including nucleophilic substitution by the fluoride ion as the keystep. Both the purified form and crude preparation of arylmalonate decarboxylase in E. coli worked well on this substrate, and (R)-α-flurophenylacetic acid (>99% e.e.) was prepared in a quantitative yield.
- Fukuyama, Yasuaki,Matoishi, Kaori,Iwasaki, Masakazu,Takizawa, Eiji,Miyazaki, Mamoru,Ohta, Hiromichi,Hanzawa, Satoshi,Kakidani, Hitoshi,Sugai, Takeshi
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- Intermetallic coinage metal-catalyzed functionalization of alkanes with ethyl diazoacetate: Gold as a ligand
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The complexes [Au2M2(C6F5) 4(NCMe)2]n (M = Cu, 1; M = Ag, 2) have been tested as catalysts for the functionalization of alkanes by the carbene insertion methodology, using ethyl diazoacetate as the carbene source. Moderate to high conversions have been obtained. The observed selectivities seem to favor the proposal that the active metal for catalysis is the Cu/Ag center, the Au(C6F5)2 unit acting as a spectator ligand in both cases.
- Fuentes, M. ángeles,Rodríguez-Castillo, María,Monge, Miguel,Olmos, M. Elena,López-De-Luzuriaga, Jose M.,Caballero, Ana,Pérez, Pedro J.
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- An improved method for preparation of carboxylic esters using CsF- celite/alkyl halide/CH3CN combination
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A new method for efficient and chemoselective esterification of carboxylic acids in CsF-Celite/alkyl halide/CH3CN reaction system is described.
- Lee, Jong Chan,Choi, Youngsup
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- Aromatization and hydrogen-shift of 7-substituted 1,3,5-cycloheptatrienes in the presence of palladium(II) acetate
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Reaction of 7-ethoxycarbonyl-1,3,5-cycloheptatriene with palladium(II) acetate afforded 2- and 4-formylbenzoic acid ethyl ester and diethyl maleate via aromatization, and a mixture of position isomers of the cycloheptatriene through hydrogen-shift. The reaction with 7-cyano-1,3,5-cycloheptatriene was also investigated. The reactions are considered to proceed through palladium complexes of the cycloheptatrienes and their norcaradiene isomers.
- Saito,Kozaki,Takahashi
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- Preparation of silica-supported sulfate and its application as a stable and highly active solid acid catalyst
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Silica sulfate was prepared by a simple procedure, and proved to be an efficient and recyclable solid acid catalyst. SO3H groups were successfully introduced to silica surface while keeping its structure intact, as proved by XRD patterns and SEM images of the catalyst. With the catalysis of the supported sulfate materials, many of the ketones are efficiently transformed into the corresponding lactones with 30% hydrogen peroxide. In addition, the high performance of silica sulfate as a heterogeneous catalyst was further demonstrated for the esterification of varieties of carboxylic acid with ethanol.
- Yang, Zhi-Wang,Niu, Leng-Yuan,Jia, Xiao-Jie,Kang, Qiao-Xiang,Ma, Zhen-Hong,Lei, Zi-Qiang
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- Synthese electrochemique d'esters arylacetique et arylpropionique via des complexes du nickel
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Aryl acetic and aryl propionic esters are obtained by an electrochemical process.The ?-arylnickel complex ArNiXL2 (L = PPh3) obtained in the presence of an aromatic halide with THF/HMPT or THF/NMP as solvent reacts with α halide aliphatic esters to give the corresponding aryl-substituted esters.
- Folest, J. C.,Perichon, J.,Fauvarque, J. F.,Jutand, A.
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- 3-ACYL-2-(N-CYANOIMINO)THIAZOLIDINES AS AN ACYLATING AGENT. PREPARATION OF AMIDES, ESTERS, AND THIOESTERS
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3-Acyl-2-(N-cyanoimino)thiazolidines proved to be powerful acylating agents.They reacted easily with amines, alcohols and thiols to give the corresponding amides, esters and thioesters in good yields.
- Iwata, Chuzo,Watanabe, Mayumi,Okamoto, Shigeha,Fujimoto, Michitaro,Sakae, Masatoshi,et al.
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- Copper(I) iodide-catalysed arylation of acetoacetate to yield 2-arylacetic acid esters
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The C-C coupling reaction between ethyl acetoacetate and aryl halides in the presence of CuI is described. The effects of solvent, ligands such as vicinal diamines and amino acids, base and temperature are reported. The arylated acetoacetate ester is deacylated under the reaction conditions resulting in the generation of 2-arylacetic acid esters, constituting a mild alternative to direct arylation of carboxylate esters.
- Zeevaart, Jacob G.,Parkinson, Christopher J.,de Koning, Charles B.
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- Synthesis of esters in the presence of chlorosilanes
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Esterification of various carboxylic acids with primary alcohols in the presence of chloro(methyl)-silanes provides a simple and convenient synthetic route to esters.
- Kozhukhova,Kalyuzhnaya,Yatluk,Suvorov
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- Remarkable co-catalysis by copper(I) oxide in the palladium catalyzed cross-coupling of arylboronic acids with ethyl bromoacetate
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Copper(I) oxide can effectively co-catalyze the Suzuki type cross-coupling reactions of arylboronic acids with ethyl bromoacetate. As an alternative protocol for introducing the methylenecarboxy group into functionalized molecules, this reaction occurs in
- Liu, Xing-Xin,Deng, Min-Zhi
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- Synthesis of arylacetic acid derivatives from diethyl malonate using in situ formed palladium(1,3-dialkylimidazolidin-2-ylidene) catalysts
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The in situ prepared three component system Pd(OAc)2/1,3- bis(alkyl) imidazolinium halide LHX (1-5)/Cs2CO3 catalyses the arylation of diethyl malonate efficiently with accompanying dealkoxycarbonylation. Imidazolinium salts with bulky benzyl and alkoxyethyl groups were found to be the most efficient and afforded α-arylacetates in high yields when employing a wide variety of substrates.
- ?zdemir, Ismail,Yigit, Murat,?etinkaya, Engin,?etinkaya, Bekir
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- Palladium-catalysed arylation of acetoacetate esters to yield 2-arylacetic acid esters
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The coupling reaction between ethyl acetoacetate and a number of aryl halides in the presence of palladium acetate, a bulky and electron rich phosphine and K3PO4 is described. The arylated acetoacetate ester is de-acylated under the reaction conditions resulting in the generation of 2-arylacetic acid esters, constituting a mild alternative to direct arylation of carboxylate esters.
- Zeevaart, Jacob G.,Parkinson, Christopher J.,De Koning, Charles B.
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- A Convenient and Stable Heterogeneous Nickel Catalyst for Hydrodehalogenation of Aryl Halides Using Molecular Hydrogen
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Hydrodehalogenation is an effective strategy for transforming persistent and potentially toxic organohalides into their more benign congeners. Common methods utilize Pd/C or Raney-nickel as catalysts, which are either expensive or have safety concerns. In this study, a nickel-based catalyst supported on titania (Ni-phen@TiO2-800) is used as a safe alternative to pyrophoric Raney-nickel. The catalyst is prepared in a straightforward fashion by deposition of nickel(II)/1,10-phenanthroline on titania, followed by pyrolysis. The catalytic material, which was characterized by SEM, TEM, XRD, and XPS, consists of nickel nanoparticles covered with N-doped carbon layers. By using design of experiments (DoE), this nanostructured catalyst is found to be proficient for the facile and selective hydrodehalogenation of a diverse range of substrates bearing C?I, C?Br, or C?Cl bonds (>30 examples). The practicality of this catalyst system is demonstrated by the dehalogenation of environmentally hazardous and polyhalogenated substrates atrazine, tetrabromobisphenol A, tetrachlorobenzene, and a polybrominated diphenyl ether (PBDE).
- Anwar, Muhammad,Beller, Matthias,Dastgir, Sarim,Junge, Kathrin,Leonard, David K.,Ryabchuk, Pavel
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- Copper-Catalyzed Ullmann-Type Coupling and Decarboxylation Cascade of Arylhalides with Malonates to Access α-Aryl Esters
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We have developed a high-efficiency and practical Cu-catalyzed cross-coupling to directly construct versatile α-aryl-esters by utilizing readily available aryl bromides (or chlorides) and malonates. These gram-scale approaches occur with turnovers of up to 1560 and are smoothly conducted by the usage of a low catalyst loading, a new available ligand, and a green solvent. A variety of functional groups are tolerated, and the application occurs with α-aryl-esters to access nonsteroidal anti-inflammatory drugs (NSAIDs) on the gram scale.
- Chen, Fen-Er,Chen, Tao,Cheng, Fei,Huang, Yin-Qiu,Li, Jia-Wei,Xiao, Xiao,Zhou, Chen
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supporting information
(2022/01/04)
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- Mechanism of Alkyl Chloroformate-Mediated Esterification of Carboxylic Acids in Aqueous Media
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The protection of carboxyl groups by esterification has been the most common method in macroscale and microscale chemistries. The esterification is usually conducted under anhydrous conditions; however, in biological chemistry and related fields, the reaction is of major concern in aqueous environments. Immediate esterification of the carboxyl in aqueous alcoholic media driven by an alkyl chloroformate and pyridine has been such a method which has found widespread use in many research and industrial laboratories. Nevertheless, the reaction mechanism has not yet been investigated, to our knowledge, and is not well understood. Herein, we describe the reaction intermediates and demonstrate that the reaction proceeds via a continual formation of the N-acylpyridinium intermediate decomposed by several reaction channels to the final ester. The understanding of the mechanism could encourage novel laboratory applications of this important esterification method.
- Opekar, Stanislav,Kví?ala, Jaroslav,Moos, Martin,Pejchal, Vladimír,?imek, Petr
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p. 16293 - 16299
(2021/10/12)
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- Expedient discovery for novel antifungal leads: 1,3,4-Oxadiazole derivatives bearing a quinazolin-4(3H)-one fragment
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Developing novel fungicide candidates are intensively promoted by the rapid emergences of resistant fungi that outbreak on agricultural production. Aiming to discovery novel antifungal leads, a series of 1,3,4-oxadiazole derivatives bearing a quinazolin-4(3H)-one fragment were constructed for evaluating their inhibition effects against phytopathogenic fungi in vitro and in vivo. Systematically structural optimizations generated the bioactive molecule I32 that was identified as a promising inhibitor against Rhizoctonia solani with the in vivo preventative effect of 58.63% at 200 μg/mL. The observations that were captured by scanning electron microscopy and transmission electron microscopy demonstrated that the bioactive molecule I32 could induce the sprawling growth of hyphae, the local shrinkage and rupture on hyphal surfaces, the extreme swelling of vacuoles, the striking distortions on cell walls, and the reduction of mitochondria numbers. The above results provided an indispensable complement for the discovery of antifungal lead bearing a quinazolin-4(3H)-one and 1,3,4-oxadiazole fragment.
- Chai, Jianqi,Chen, Min,Jin, Fei,Kong, Xiangyi,Wang, Xiaobin,Xue, Wei,Yang, Chunlong
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- Hydrogen-Bonding Assisted Catalytic Kinetic Resolution of Acyclic β-Hydroxy Amides
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Enantioenriched acyclic α-substituted β-hydroxy amides are valuable compounds in chemical, material and medicinal sciences, but their enantioselective synthesis remains challenging. A catalytic kinetic resolution (KR) of such amides with selectivity factor(s) up to >200 is developed via enantioselective acylation of primary alcohol with N-heterocyclic carbene. An enhanced selectivity for the catalytic KR process is realized using cyclic tertiary amine as base additive. Diastereomeric transition state models for the process are proposed to rationalize the origin of enantioselectivity.
- Porey, Arka,Mondal, Bhaskar Deb,Guin, Joyram
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supporting information
p. 8786 - 8791
(2021/03/17)
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- Photoinduced Diverse Reactivity of Diazo Compounds with Nitrosoarenes
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A diverse reactivity of diazo compounds with nitrosoarene in an oxygen-transfer process and a formal [2 + 2] cycloaddition is reported. Nitosoarene has been exploited as a mild oxygen source to oxidize an in situ generated carbene intermediate under visible-light irradiation. UV-light-mediated in situ generated ketenes react with nitosoarenes to deliver oxazetidine derivatives. These operationally simple processes exemplify a transition-metal-free and catalyst-free protocol to give structurally diverse α-ketoesters or oxazetidines.
- Roy, Sourav,Kumar, Gourav,Chatterjee, Indranil
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p. 6709 - 6713
(2021/09/08)
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- Coupling of Reformatsky Reagents with Aryl Chlorides Enabled by Ylide-Functionalized Phosphine Ligands
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The coupling of aryl chlorides with Reformatsky reagents is a desirable strategy for the construction of α-aryl esters but has so far been substantially limited in the substrate scope due to many challenges posed by various possible side reactions. This limitation has now been overcome by the tailoring of ylide-functionalized phosphines to fit the requirements of Negishi couplings. Record-setting activities were achieved in palladium-catalyzed arylations of organozinc reagents with aryl electrophiles using a cyclohexyl-YPhos ligand bearing an ortho-tolyl-substituent in the backbone. This highly electron-rich, bulky ligand enables the use of aryl chlorides in room temperature couplings of Reformatsky reagents. The reaction scope covers diversely functionalized arylacetic and arylpropionic acid derivatives. Aryl bromides and chlorides can be converted selectively over triflate electrophiles, which permits consecutive coupling strategies.
- Hu, Zhiyong,Wei, Xiao-Jing,Handelmann, Jens,Seitz, Ann-Katrin,Rodstein, Ilja,Gessner, Viktoria H.,Goo?en, Lukas J.
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supporting information
p. 6778 - 6783
(2021/02/01)
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- Switching from Single to Simultaneous Free-Radical and Anionic Polymerization with Enamine-Based Organic Electron Donors
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Although most monomers can polymerize through different propagation pathways, polymerization-initiating systems that can switch from one mode to another are rare. In this study, we demonstrate that enamine-based organic electron donors (OEDs) constitute the first systems able to initiate either free-radical or anionic polymerization under simple, mild, and safe conditions. While direct electron-transfer reduction of monomers by OEDs results in the initiation of anionic chain-growth polymerization, introduction of a competing oxidant with a higher reduction potential than the monomer switches the former anionic propagation to a clean radical-propagation process. The benefit of this dual-mode activator is highlighted in the synthesis of an interpenetrating polymer network through simultaneous initiation of radical and anionic propagation processes.
- Broggi, Julie,Canard, Gabriel,Charles, Laurence,Gigmes, Didier,Rollet, Marion,Vanelle, Patrice,Zhao, Yuxi
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supporting information
p. 19389 - 19396
(2021/07/26)
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- Synthesis of Dithiolethiones and Identification of Potential Neuroprotective Agents via Activation of Nrf2-Driven Antioxidant Enzymes
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Oxidative stress is implicated in the pathogenesis of a wide variety of neurodegenerative disorders, and accordingly, dietary supplement of exogenous antioxidants or/and upregulation of the endogenous antioxidant defense system are promising for therapeutic intervention or chemoprevention of neurodegenerative diseases. Nrf2, a master regulator of the cellular antioxidant machinery, cardinally participates in the transcription of cytoprotective genes against oxidative/electrophilic stresses. Herein, we report the synthesis of 59 structurally diverse dithiolethiones and evaluation of their neuroprotection against 6-hydroxydopamine-or H2O2-induced oxidative damages in PC12 cells, a neuron-like rat pheochromocytoma cell line. Initial screening identified compounds 10 and 11 having low cytotoxicity but conferring remarkable protection on PC12 cells from oxidative-mediated damages. Further studies demonstrated that both compounds upregulated a battery of antioxidant genes as well as corresponding genes' products. Significantly, silence of Nrf2 expression abolishes cytoprotection of 10 and 11, indicating targeting Nrf2 activation is pivotal for their cellular functions. Taken together, the two lead compounds discovered here with potent neuroprotective functions against oxidative stress via Nrf2 activation merit further development as therapeutic or chemopreventive candidates for neurodegenerative disorders.
- Bai, Feifei,Fang, Jianguo,Song, Zi-Long,Zhang, Baoxin
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p. 2214 - 2231
(2020/03/06)
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- Cu(I)/chiral bisoxazoline-catalyzed enantioselective sommelet-hauser rearrangement of sulfonium ylides
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Catalytic asymmetric thia-Sommelet-Hauser rearrangement of sulfonium ylides remains a great challenge due to its multistep reaction mechanism involving metal carbene formation, proton transfer, and [2,3]-sigmatropic rearrangement. In particular, the key problem of such reactions is the differentiation of the enantiotopic lone pair electrons of sulfur, which generates the sulfonium ylide intermediate bearing chirality on the sulfur atom. With a modified chiral bisoxazoline ligand, we developed a Cu(I)- catalyzed asymmetric thia-Sommelet-Hauser rearrangement with good to excellent enantioselectivities. Mechanistic studies provide insights into the details of the reaction mechanism.
- Wang, Jianbo,Li, Shu-Sen
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supporting information
p. 12343 - 12358
(2020/11/10)
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- Blue Light-Promoted N?H Insertion of Carbazoles, Pyrazoles and 1,2,3-Triazoles into Aryldiazoacetates
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Blue light irradiation of aryldiazoacetates leads to the formation of free carbenes, which can react with carbazoles, pyrazoles and 1,2,3-triazoles to afford the corresponding N?H inserted products. These reactions are performed under air and at room temperature, allowing the mild preparation of a variety of motifs found in biologically relevant targets. (Figure presented.).
- Stivanin, Mateus L.,Fernandes, Alessandra A. G.,da Silva, Amanda F.,Okada, Celso Y.,Jurberg, Igor D.
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p. 1106 - 1111
(2020/01/25)
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- Alkoxydiaminophosphine Ligands as Surrogates of NHCs in Copper Catalysis
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A family of phosphine ligands containing a five-membered ring similar to the popular N-heterocyclic carbene ligands and an alkoxy third substituent has been developed. These alkoxydiaminophosphine ligands (ADAP) can be generated in one pot and reacted with a copper(I) source leading to the high yield isolation of complexes [(ADAP)CuX]2 (X=Cl, Br). The dinuclear nature of these compounds has been established by means of X-ray studies and DOSY experiments. A screening of the catalytic properties of these complexes toward carbene-transfer reactions from diazocompounds to C?H bonds (alkane, arene), olefins or N?H bonds, as well as in CuAAC or nitrene transfer reactions have shown a performance at least similar, if not better, than their (NHC)CuCl analogues, opening a new window in copper catalysis with these readily tunable ADAP ligands.
- Pizarro, Juan Diego,Molina, Francisco,Fructos, Manuel R.,Pérez, Pedro J.
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supporting information
p. 10330 - 10335
(2020/07/24)
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- Metal-Free Oxidative Esterification of Ketones and Potassium Xanthates: Selective Synthesis of α-Ketoesters and Esters
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A novel and efficient oxidative esterification for the selective synthesis of α-ketoesters and esters has been developed under metal-free conditions. In the protocol, various α-ketoesters and esters are available in high yields from commercially available ketones and potassium xanthates. Mechanistic studies have proven that potassium xanthate not only promotes oxidative esterification but also provides an alkoxy moiety for the reaction, which involves the cleavage and reconstruction of C-O bonds.
- Luo, Xianglin,He, Runfa,Liu, Qiang,Gao, Yanping,Li, Jingqing,Chen, Xiuwen,Zhu, Zhongzhi,Huang, Yubing,Li, Yibiao
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p. 5220 - 5230
(2020/05/18)
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- Preparation of Organic Nitrates from Aryldiazoacetates and Fe(NO3)3·9H2O
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A thermal protocol is reported for the formal insertion of nitric acid into aryldiazoacetates using Fe(NO3)3·9H2O. This strategy is mild and high yielding and allows the preparation of a large variety of members of an unprecedented family of organic nitrates. The nitrate group can be also readily transformed into other functional groups and heterocyclic moieties and can possibly allow new biological explorations of untapped potential associated with their NO-releasing ability.
- Thurow, Samuel,Fernandes, Alessandra A. G.,Quevedo-Acosta, Yovanny,De Oliveira, Matheus F.,De Oliveira, Marcelo G.,Jurberg, Igor D.
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p. 6909 - 6913
(2019/09/12)
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- Palladium oxide nanoparticles supported on graphene oxide: A convenient heterogeneous catalyst for reduction of various carbonyl compounds using triethylsilane
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Palladium oxide nanoparticles supported on graphene oxide - triethylsilane was found to be an effective reductive system for a broad range of reduction processes, including the reduction of various carbonyl compounds such as aromatic aldehydes to their corresponding alcohols or methyl arene compounds, aromatic ketones to their respective alcohols or saturated compounds, aromatic acyl chlorides to their reduced compounds. The desired products were obtained in good to excellent yields under mild conditions. The heterogeneous environmentally friendly catalyst can be easily separated from the reaction mixture through a simple filtration, facilitating purification of the prepared compounds.
- Mirza-Aghayan, Maryam,Kalantari, Meisam,Boukherroub, Rabah
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- A sustainable procedure toward alkyl arylacetates: Palladium-catalysed direct carbonylation of benzyl alcohols in organic carbonates
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A sustainable procedure for the synthesis of various alkyl arylacetates from benzyl alcohols has been developed. With palladium as the catalyst and organic carbonates as the green solvent and in situ activator, benzyl alcohols were carbonylated in an efficient manner without any halogen additives.
- Li, Yahui,Wang, Zechao,Wu, Xiao-Feng
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supporting information
p. 969 - 972
(2018/03/13)
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- Fe-catalyzed esterification of amides via C-N bond activation
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An efficient Fe-catalyzed esterification of primary, secondary, and tertiary amides with various alcohols for the preparation of esters was performed. The esterification process was accomplished with FeCl3$6H2O, which is a stable, inexpensive, environmentally friendly catalyst with high functional group tolerance.
- Chen, Xiuling,Hu, Siying,Chen, Rongxing,Wang, Jian,Wu, Minghu,Guo, Haibin,Sun, Shaofa
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p. 4571 - 4576
(2018/02/09)
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- Dynamic kinetic resolution of bis-aryl succinic anhydrides: Enantioselective synthesis of densely functionalised γ-butyrolactones
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The efficient Dynamic Kinetic Resolution (DKR) of disubstituted anhydrides has been shown to be possible for the first time. Using an ad hoc designed organocatalyst and an enantio- and diastereoselective cycloaddition process with aldehydes, stereochemically complex γ-butyrolactone derivatives can be obtained-with control over three contiguous stereocentres, one of which is all carbon quaternary.
- Claveau, Romain,Twamley, Brendan,Connon, Stephen J.
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supporting information
p. 3231 - 3234
(2018/04/05)
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- Synthesis of α-alkylated γ-butyrolactones with concomitant anhydride kinetic resolution using a sulfamide-based catalyst
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The Kinetic Resolution (KR) of α-alkylated enolisable disubstituted anhydrides has been shown to be possible for the first time. In the presence of an ad hoc designed novel class of bifunctional sulfamide organocatalyst, a regio-, diastereo- and enantioselective cycloaddition reaction between the enolisable anhydride and benzaldehydes provides densely functionalised γ-butyrolactones in one pot (up to 19:1 dr, 94% ee) with control over three contiguous stereocentres. The concomitant resolution of the starting material anhydride, provides access to a range of chiral succinate derivatives with selectivity factors up to S? = 10.5.
- Claveau, Romain,Twamley, Brendan,Connon, Stephen J.
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supporting information
p. 7574 - 7578
(2018/11/02)
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- Synthesis and characterization of stable ZnO nanoparticles using imidazolium-based ionic liquids and their applications in esterification reaction
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ZnO nanoparticles have been synthesized from zinc acetate using 1-octyl-3-methylimidazolium hexafluorophosphate as capping agent under microwave irradiation condition in a very short period of time and characterized using UV-visible spectroscopy, powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy and NH3-TPD analysis. The ZnO NPs have been used as a solid reusable acid catalyst for esterification of carboxylic acids with alcohols.
- Kavya,Vijaya Kumar,Ramesh Kumar
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p. 1112 - 1120
(2018/09/21)
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- Mechanism of the Selective Fe-Catalyzed Arene Carbon-Hydrogen Bond Functionalization
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The complete chemoselective functionalization of aromatic C(sp2)-H bonds of benzene and alkyl benzenes by carbene insertion from ethyl diazoacetate was unknown until the recent discovery of an iron-based catalytic system toward such transformation. A Fe(II) complex bearing the pytacn ligand (pytacn = L1 = 1-(2-pyridylmethyl)-4,7-dimethyl-1,4,7-triazacyclononane) transferred the CHCO2Et unit exclusively to the C(sp2)-H bond. The cycloheptatriene compound commonly observed through Buchner reaction or, when employing alkyl benzenes, the corresponding derivatives from C(sp3)-H functionalization are not formed. We herein present a combined experimental and computational mechanistic study to explain this exceptional selectivity. Our computational study reveals that the key step is the formation of an enol-like substrate, which is the precursor of the final insertion products. Experimental evidences based on substrate probes and isotopic labeling experiments in favor of this mechanistic interpretation are provided.
- Postils, Verònica,Rodríguez, Mònica,Sabenya, Gerard,Conde, Ana,Díaz-Requejo, M. Mar,Pérez, Pedro J.,Costas, Miquel,Solà, Miquel,Luis, Josep M.
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p. 4313 - 4322
(2018/05/22)
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- Palladium-Catalyzed Carbonylative Direct Transformation of Benzyl Amines under Additive-Free Conditions
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In this communication, we developed a new procedure for the direct carbonylative transformation of benzyl amines. Using dimethyl carbonate as the solvent, methyl 2-arylacetates can be produced in good to excellent yields from the corresponding primary, secondary, and tertiary benzyl amines with palladium as the catalyst. Notably, no base or any other additive is required here. In addition, our procedure can also be applied in the preparation of methylphenidate, which is a marketing drug and used in the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy.
- Li, Yahui,Wang, Zechao,Wu, Xiao-Feng
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p. 738 - 741
(2018/01/17)
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- Palladium-catalyzed carbonylation of benzylic ammonium salts to amides and esters: Via C-N bond activation
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An efficient palladium-catalyzed carbonylation reaction of readily available quaternary ammonium salts with CO is reported for the first time to afford arylacetamides and arylacetic acid esters via benzylic C-N bond cleavage. This protocol features mild reaction conditions under atmospheric pressure of CO, a redox-neutral process without an additional oxidant, and a broad substrate scope for various kinds of amines, alcohols and phenols.
- Yu, Weijie,Yang, Shuwu,Xiong, Fei,Fan, Tianxiang,Feng, Yan,Huang, Yuanyuan,Fu, Junkai,Wang, Tao
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p. 3099 - 3103
(2018/05/22)
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- Rh(III)-Catalyzed Enaminone-Directed C-H Coupling with α-Diazo-α-phosphonoacetate for Reactivity Discovery: Fluoride-Mediated Dephosphonation for C-C Coupling Reactions
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Rh(III)-catalyzed enaminone-directed C-H coupling with α-diazo-α-phosphonoacetate has been used for the identification of fluoride-mediated dephosphonation C-C coupling reactivity for the synthesis of 4-hydroxy-1-naphthoates. Intermolecular C-C coupling of α-phosphonoacetate and benzaldehyde for (E)-selective α,β-unsaturated ester synthesis has also been achieved.
- Song, Chao,Yang, Chen,Zeng, Hua,Zhang, Wenjing,Guo, Shan,Zhu, Jin
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p. 3819 - 3823
(2018/07/22)
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- Palladium-Catalyzed Decarboxylative Carbonylative Transformation of Benzyl Aryl Carbonates: Direct Synthesis of Aryl 2-Arylacetates
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A procedure on palladium-catalyzed decarboxylative alkoxycarbonylation of carbonates for the synthesis of aryl 2-arylacetates has been developed. A broad range of aryl 2-arylacetates were obtained in good yields under mild conditions under a carbon monoxide atmosphere. Interestingly, other alcohols can be added as nucleophiles as well, and the corresponding esters were also obtained in good yields.
- Xu, Jian-Xing,Wu, Xiao-Feng
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supporting information
p. 5938 - 5941
(2018/09/21)
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- Overriding Traditional Electronic Effects in Biocatalytic Baeyer-Villiger Reactions by Directed Evolution
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Controlling the regioselectivity of Baeyer-Villiger (BV) reactions remains an ongoing issue in organic chemistry, be it by synthetic catalysts or enzymes of the type Baeyer-Villiger monooxygenases (BVMOs). Herein, we address the challenging problem of switching normal to abnormal BVMO regioselectivity by directed evolution using three linear ketones as substrates, which are not structurally biased toward abnormal reactivity. Upon applying iterative saturation mutagenesis at sites lining the binding pocket of the thermostable BVMO from Thermocrispum municipale DSM 44069 (TmCHMO) and using 4-phenyl-2-butanone as substrate, the regioselectivity was reversed from 99:1 (wild-type enzyme in favor of the normal product undergoing 2-phenylethyl migration) to 2:98 in favor of methyl migration when applying the best mutant. This also stands in stark contrast to the respective reaction using the synthetic reagent m-CPBA, which provides solely the normal product. Reversal of regioselectivity was also achieved in the BV reaction of two other linear ketones. Kinetic parameters and melting temperatures revealed that most of the evolved mutants retained catalytic activity, as well as thermostability. In order to shed light on the origin of switched regioselectivity in reactions of 4-phenyl-2-butanone and phenylacetone, extensive QM/MM and MD simulations were performed. It was found that the mutations introduced by directed evolution induce crucial changes in the conformation of the respective Criegee intermediates and transition states in the binding pocket of the enzyme. In mutants that destabilize the normally preferred migration transition state, a reversal of regioselectivity is observed. This conformational control of regioselectivity overrides electronic control, which normally causes preferential migration of the group that is best able to stabilize positive charge. The results can be expected to aid future protein engineering of BVMOs.
- Li, Guangyue,Garcia-Borràs, Marc,Fürst, Maximilian J. L. J.,Ilie, Adriana,Fraaije, Marco W.,Houk,Reetz, Manfred T.
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supporting information
p. 10464 - 10472
(2018/08/03)
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- Method of converting amide and urea into ester
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The invention provides a method of converting amide and urea into ester. In the method, different types of amide and urea are used as substrate, alcohol or phenol is used as nucleophile, iron salt is used as catalyst, and acid is used as additive, the conversion of amide and urea into ester is achieved under a mild condition. The method is characterized in that cheap iron salt is used as the catalyst, the commercialized amide, urea, and alcohol are used as the substrate, and the conversion of amide to ester is achieved in one step. The method has the advantages that the reaction condition is mild, the raw materials are cheap and easy to obtain, the reaction substrate is wide in adaptability, the selectivity and yield of the product are very high, the product is green and environmentally friendly and the like, and the method has good prospects for industrial applications.
- -
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Paragraph 0054-0056
(2017/08/30)
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- A novel serine racemase inhibitor suppresses neuronal over-activation in vivo
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Serine racemase (SRR) is an enzyme that produces D-serine from L-serine. D-Serine acts as an endogenous coagonist of NMDA-type glutamate receptors (NMDARs), which regulate many physiological functions. Over-activation of NMDARs induces excitotoxicity, which is observed in many neurodegenerative disorders and epilepsy states. In our previous works on the generation of SRR gene knockout (Srr-KO) mice and its protective effects against NMDA- and Aβ peptide-induced neurodegeneration, we hypothesized that the regulation of NMDARs’ over-activation by inhibition of SRR activity is one such therapeutic strategy to combat these disease states. In the previous study, we performed in silico screening to identify four compounds with inhibitory activities against recombinant SRR. Here, we synthesized 21 derivatives of candidate 1, one of four hit compounds, and performed screening by in vitro evaluations. The derivative 13J showed a significantly lower IC50 value in vitro, and suppressed neuronal over-activation in vivo.
- Mori, Hisashi,Wada, Ryogo,Takahara, Satoyuki,Horino, Yoshikazu,Izumi, Hironori,Ishimoto, Tetsuya,Yoshida, Tomoyuki,Mizuguchi, Mineyuki,Obita, Takayuki,Gouda, Hiroaki,Hirono, Shuichi,Toyooka, Naoki
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p. 3736 - 3745
(2017/06/13)
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- Design, synthesis, biological evaluation, and 3D-QSAR analysis of podophyllotoxin–dioxazole combination as tubulin targeting anticancer agents
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The advancement of cancer-fighting drugs has never been a simple linear process. Those drug design professionals begin to find inspiration from the nature after failing to find the ideal products by creative drug design and high-throughput screening. To obtain new molecules for inhibiting tubulin, podophyllotoxin was adopted as the leading compound and 1,3,4-oxadiazole was brought in to the C-4 site of podophyllotoxin in this research. A series of seventeen podophyllotoxin-derived esters have been achieved and then evaluated their antitumor activities against four different cancer cell lines: A549, MCF-7, HepG2, and HeLa. Among all the compounds, compound 7c showed the best antiproliferating properties with IC50?=?2.54?±?0.82?μm against MCF-7 cancer cell line. It was obvious that the content of ROS grew significantly in MCF-7 in a way depending on the dosage. The time- and dose-dependent cell cycle assays revealed that compound 7c could apparently block cell cycle in the phase of G2/M along with the upregulation of cyclin A2 and CDK2 protein. According to further studies, confocal microscopy experiment has certified that compound 7c could restrain cancer from growing by blocking the polymerization of microtubule. Meanwhile, compound 7c could be ideally integrated with the colchicine site of tubulin. In future, it would be feasible to selectively design tubulin inhibitors with the help of 3D-QSAR. This means that it is hopeful to develop compound 7c as a potential agent against cancer due to its biological characteristics.
- Wang, Zi-Zhen,Sun, Wen-Xue,Wang, Xue,Zhang, Ya-Han,Qiu, Han-Yue,Qi, Jin-Liang,Pang, Yan-Jun,Lu, Gui-Hua,Wang, Xiao-Ming,Yu, Fu-Gen,Yang, Yong-Hua
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p. 236 - 243
(2017/07/13)
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- Synthesis, spectral analysis and antibacterial evaluation of 5-substituted-1,3,4-oxadiazol-2-yl 4-(4-methylpiperidin-1-ylsulfonyl)benzyl sulfides
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Owing to valuable biological activities of 1,3,4-oxadiazole, sulfamoyl and piperidine functionalities, some new 1-(4-{[(5-substituted-1,3,4-oxadiazol-2-yl) thio]methyl}benzene sulfonyl)-4-methylpiperidine (6a-o) derivatives have been introduced. The target molecules were synthesized from different aralkyl/aryl carboxylic acids, 1a-o, through a series of steps. First the compounds, 1a-o, were converted to heterocyclic 1,3,4-oxadiazole nucleophiles, 4a-o. Second an electrophile as 1-(4-bromomethylbenzenesulfonyl)-4-methylpiperidine (5) was synthesized from 4-methylpiperidine. Finally the target compounds, 6a-o, were prepared by reacting 4a-o with 5 in DMF and LiH. The final compounds were structurally elucidated by spectral data of IR, 1H-NMR and EI-MS. All the compounds were screened for their antibacterial evaluation and found to exhibit valuable results.
- Aziz-Ur-Rehman,Ahtzaz, Samreen,Abbasi, Muhammad Athar,Siddiqui, Sabahat Zahra,Rasool, Shahid,Ahmad, Irshad
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p. 3370 - 3375
(2017/05/22)
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- Synthesis and pharmacological screening: Sulfa derivatives of 2-pipecoline-bearing 1,3,4-oxadiazole core
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An electrophile, 1-(4-(bromomethylbenzenesulfonyl)-2-methylpiperidine, was synthesized by the reaction of 2-methylpiperidine (2-pipecoline) and 4-bromomethylbenzenesulfonyl chloride in a weak basic medium under pH control. A series of nucleophiles, 5-aryl/aralkyl-1,3,4-oxadiazol-2-thiols, were synthesized from corresponding carboxylic acids in three steps. The title molecules were synthesized by coupling the electrophile to nucleophiles in an aprotic medium using LiH as an activator. The structures of all synthesized compounds were corroborated through IR, 1H NMR, and EI-MS techniques. All the compounds were screened for their pharmacological behavior, particularly, antibacterial and enzyme inhibitory activities. Notably efficient results were obtained against both gram-positive and gram-negative bacterial strains. Regarding enzyme inhibition, compounds were efficient against acetylcholinesterase and butyrylcholinesterase.
- Aziz-ur-Rehman,Arif,Abbasi,Siddiqui,Rasool,Shah
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p. 328 - 339
(2017/07/04)
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- Organoselenium-Catalyzed Oxidative C=C Bond Cleavage: A Relatively Green Oxidation of Alkenes into Carbonyl Compounds with Hydrogen Peroxide
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A relatively green oxidative C=C bond cleavage of alkenes was achieved by organoselenium-catalyzed alkene oxidation reaction in ethanol with hydrogen peroxide, affording carbonyl compounds under relatively mild conditions. It is a new reaction style for the organoselenium-catalyzed oxidation of alkenes and largely contributes to the growing field of organoselenium catalysis.
- Wang, Tingting,Jing, Xiaobi,Chen, Chao,Yu, Lei
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p. 9342 - 9349
(2017/09/23)
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- Enantioselective Hydrogen Atom Transfer: Discovery of Catalytic Promiscuity in Flavin-Dependent 'Ene'-Reductases
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Flavin has long been known to function as a single electron reductant in biological settings, but this reactivity has rarely been observed with flavoproteins used in organic synthesis. Here we describe the discovery of an enantioselective radical dehalogenation pathway for α-bromoesters using flavin-dependent 'ene'-reductases. Mechanistic experiments support the role of flavin hydroquinone as a single electron reductant, flavin semiquinone as the hydrogen atom source, and the enzyme as the source of chirality.
- Sandoval, Braddock A.,Meichan, Andrew J.,Hyster, Todd K.
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supporting information
p. 11313 - 11316
(2017/08/30)
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- Mechanistic studies on gold-catalyzed direct arene c-h bond functionalization by carbene insertion: The coinage-metal effect
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The catalytic functionalization of the Csp2-H bond of benzene by means of the insertion of the CHCO2Et group from ethyl diazoacetate (N2= CHCO2Et) has been studied with the series of coinage-metal complexes IPrMCl (IPr = 1,3-bis- (diisopropylphenyl)imidazol-2-ylidene) and NaBArF 4 (BArF 4 = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate). For Cu and Ag, these examples constitute the first use of such metals toward this transformation, which also provides ethyl cyclohepta-2,4,6-trienecarboxylate as a byproduct from the so-called Buchner reaction. In the case of methyl-substituted benzenes, the reaction exclusively proceeds onto the aromatic ring, the Csp3-H bond remaining unreacted. A significant coinage-metal effect has been observed, since the gold catalyst favors the formation of the insertion product into the Csp2-H bond whereas copper and silver preferentially induce the formation of the cycloheptatriene derivative. Experimental studies and theoretical calculations have explained the observed selectivity in terms of the formation of a common Wheland intermediate, resembling an electrophilic aromatic substitution, from which the reaction pathway evolves into two separate routes to each product.
- Fructos, Manuel R.,Besora, Maria,Braga, Ataualpa A. C,Díaz-Requejo, M. Mar,Maseras, Feliu,Perez, Pedro J.
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p. 172 - 179
(2017/04/04)
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- BTK INHIBITOR
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Provided are a series of BTK inhibitors, and specifically disclosed are a compound, pharmaceutically acceptable salt thereof, tautomer thereof or prodrug thereof represented by formula (I), (II), (III) or (IV).
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-
Paragraph 0230
(2017/11/16)
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- NOVEL CATALYST FOR ESTER EXCHANGE REACTION AND METHOD FOR PRODUCING ESTER COMPOUND USING THE SAME
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PROBLEM TO BE SOLVED: To provide a catalyst that makes an ester exchange reaction proceed on a mild condition and gives a target product at a high reaction yield, and provide a method for producing an ester compound on a mild condition. SOLUTION: The present invention provides a catalyst for ester exchange reaction comprising a dianionic zinc ate complex represented by General Formula (1) and a method for producing an ester compound using the complex (where n is an integer of 1-4 and when n is 1 or 2, Rs may be the same or different to represent a C1-C8 alkyl group, alkenyl group, aryl group, or arylalkyl group, M is lithium or magnesium, and m is 1 or 2). SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0044
(2017/02/24)
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- Iron and manganese catalysts for the selective functionalization of arene C(sp2)-H bonds by carbene insertion
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The first examples of the direct functionalization of non-activated aryl sp2 C-H bonds with ethyl diazoacetate (N2CHCO2Et) catalyzed by Mn- or Fe-based complexes in a completely selective manner are reported, with no formation of the frequently observed cycloheptatriene derivatives through competing Buchner reaction. The best catalysts are FeII or MnII complexes bearing the tetradentate pytacn ligand (pytacn= 1-(2-pyridylmethyl)-4,7-dimethyl-1,4,7-triazacyclononane). When using alkylbenzenes, the alkylic C(sp3)-H bonds of the substituents remained unmodified, thus the reaction being also selective toward functionalization of sp2 C-H bonds. Exclusive catalysis: Iron- and-manganese-based catalysts selectively functionalize the C(sp2)-H bonds of benzene or alkylbenzenes through the formal insertion of the CHCO2Et group from N2CHCO2Et (see scheme). When using alkylbenzenes, the alkylic C(sp3)-H bonds of the substituents remain unmodified.
- Conde, Ana,Sabenya, Gerard,Rodríguez, Mònica,Postils, Verònica,Luis, Josep M.,Díaz-Requejo, M. Mar,Costas, Miquel,Pérez, Pedro J.
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supporting information
p. 6530 - 6534
(2016/06/01)
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- A convenient method for reduction dehalogenation of α-halocarbonyl compounds using benzenethiol in K+/CH3CN system
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Benzenethiol, as a reductive agent for the dehalogenation of various α-halocarbonyl compounds, is investigated in the K+/CH3CN system. The reaction affords the reduced compounds in high yields under mild reaction conditions, especially α-chlorocarbonyl compounds. Furthermore, the reaction performed under ultrasonic irradiation greatly shortens the reaction time.
- Dong, Wei-Li,Cai, Wen-Xi,Wu, Rui,Li, Zheng-Ming,Zhao, Wei-Guang,Liu, Xing-Hai
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p. 980 - 983
(2016/07/06)
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- Copper(II)-Catalyzed Benzylic C(sp3)-H Aerobic Oxidation of (Hetero)Aryl Acetimidates: Synthesis of Aryl-α-ketoesters
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A straightforward method is developed in this paper for the synthesis of α-ketoesters through copper-catalyzed aerobic oxidation of (hetero)aryl acetimidates using molecular oxygen as a sustainable oxidant. The reaction represents the first example of the direct synthesis of aryl-α-ketoesters from arylacetimidates through the aerobic oxidation of a benzylic C(sp3)-H (CO) bond in moderate to good yield. This transformation occurs under mild reaction conditions with a wide range of substrates and utilizes a readily available oxidant and catalyst. The synthetic utility of this transformation is demonstrated through scaled-up synthesis. A plausible reaction mechanism is also proposed.
- Kumar, Yogesh,Jaiswal, Yogesh,Kumar, Amit
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p. 12247 - 12257
(2016/12/23)
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- An elegant synthesis of indoloquinoline alkaloid cryptotackieine via Vilsmeier-Haack approach
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An exclusive approach towards the synthesis of indoloquinoline alkaloid cryptotackiene has been illustrated. Primary starting materials with an established procedure like Vilsmeier-Haack cyclization are used followed by nucleophilic azidation, intra-molecular cyclization and a selective methylation to achieve the target.
- Pitchai,Sathiyaseelan,Nepolraj,Gengan
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p. 1290 - 1292
(2015/11/25)
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- Synthesis of 3-hydroxyindanones via potassium salt of amino acid catalyzed regioselective intramolecular aldolization of ortho-diacylbenzenes
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First organocatalytic intramolecular aldolization of ortho-diacylbenzenes to construct highly functionalized 3-hydroxyindanones is described. In this transformation a high trans-selectivity is achieved by the use of metal salt of amino acid. This method allows an easy access to the strained spirocyclic 3-hydroxyindanones related to a number of natural product frameworks. Synthesis of a new class of indole skeleton substituted by 3-hydroxyindanones added an extra essence to this new protocol.
- Chanda, Tanmoy,Chowdhury, Sushobhan,Anand, Namrata,Koley, Suvajit,Gupta, Ashutosh,Singh, Maya Shankar
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supporting information
p. 981 - 985
(2015/03/04)
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