cas 403-33-8, Methyl 4-fluorobenzoate | Articles data

Articles about 403-33-8Total 169 be found

Article title
Article abstract
Author
Journal number and time
Download

Absolute raman intensities of the carbonyl stretching band in para substituted methyl benzoates
The absolute Raman intensities of the vC=0 band of para-substituted methyl benzoates have been measured in CCl4 solution at different excitation frequencies. The intensities depend on a preresonance Raman effect (PRRE) and are correlated with theoretical expressions which describe the dispersion of the Raman intensity as a function of the excitation frequency and the experimental UV frequencies of the compounds, in particular the π→π* 1La band. The Raman intensities free from PRRE are deduced by extrapolating the experimental values to a zero excitation frequency. These extrapolated intensities depend on the electron-donating character of the substituents and on the extent of the conjugated system. The depolarization ratio of the vC=0 band in methyl benzoates increases with the excitation energies. This ratio is higher for the para-substituted derivatives.
Vanderheyden,Zeegers-Huyskens
p. 1423 - 1428
(1989)
Read Online

Aerobic oxidative cleavage and esterification of C[dbnd]C bonds catalyzed by iron-based nanocatalyst
Functionalization of C[dbnd]C bonds by oxidative cleavage plays an important role in organic synthesis. However, the traditional functionalized products are mainly aldehydes, ketones and carboxylic acids, and the substrates are limited to examples of active aromatic olefins with very scarce inactive olefins. Herein we disclose an efficient protocol for the direct formation of esters by oxidative cleavage of C[dbnd]C bonds using heterogeneous iron nanocomposite catalyst supported on nitrogen-doped carbon materials with molecular oxygen and tert-butylhydroperoxide (TBHP) as the oxidants. The results show that molecular oxygen as the terminal oxidant is mainly responsible for the cleavage process, and that the auxiliary oxidant TBHP promotes the formation of the intermediate epoxide, thus increasing the selectivity of the product. The catalytic system has a wide range of substrate compatibility involving the challenging inactive aliphatic and long-chain alkyl aryl olefins. The catalyst was reused seven times with no loss in catalytic activity. Characterization and control experiments uncover that the core-shell Fe and Fe3C nanoparticles encapsulated by graphitic carbon play a predominant role in catalyzing the oxidative cleavage of olefins to esters. Preliminary mechanistic studies disclose that this process involves both free radical reactions and tandem sequential reactions.
An, Yue,Fu, Weiru,Tan, Shangzhi,Wang, Lianyue,Yu, Xiangzhu,Zhao, Zhengjia,Zhu, Lina
(2022/02/03)

Br?nsted acid-catalyzed chlorination of aromatic carboxylic acids
The chlorination of aromatic carboxylic acids with SOCl2 has been effectively performed by reacting with a Br?nsted acid as the catalyst. Based on this discovery, an efficient catalytic method that is cheaper than traditional catalytic methods was developed. 20 substrates were chlorinated offering excellent yields in a short reaction time. And the SOCl2/Br?nsted acid system has been used in a larger scale preparative reaction. A dual activation mechanism was proposed to prove the irreplaceable system of SOCl2/Br?nsted acid.
Yu, Zhiqun,Yao, Hongmiao,Xu, Qilin,Liu, Jiming,Le, Xingmao,Ren, Minna
p. 685 - 689
(2021/04/09)

PCl3-mediated transesterification and aminolysis of tert-butyl esters via acid chloride formation
A PCl3-mediated conversion of tert-butyl esters into esters and amides in one-pot under air is developed. This novel protocol is highlighted by the synthesis of skeletons of bioactive molecules and gram-scale reactions. Mechanistic studies revealed that this transformation involves the formation of an acid chloride in situ, which is followed by reactions with alcohols or amines to afford the desired products.
Wu, Xiaofang,Zhou, Lei,Li, Fangshao,Xiao, Jing
p. 491 - 497
(2021/01/20)

Hydroxyl radical-mediated oxidative cleavage of CC bonds and further esterification reaction by heterogeneous semiconductor photocatalysis
A hydroxyl radical-mediated aerobic cleavage of alkenes and further sequence esterification reaction for the preparation of carbonyl compounds have been developed by using tubular carbon nitride (TCN) as a general heterogeneous photocatalyst under an oxygen atmosphere with visible light irradiation. This protocol has an excellent substrate scope and gives the desired aldehydes, ketones and esters in moderate to high yields. Importantly, this metal-free procedure employed photogenerated hydroxyl radicals in situ as green oxidation active species, avoiding the present additional initiators. The reaction could be carried out under solar light irradiation and was applicable to large-scale reactions. Furthermore, the recyclable TCN catalyst could be used several times without a significant loss of activities.
Hong, Mei,Jia, Rui,Miao, Hongyan,Ni, Bangqing,Niu, Tengfei,Wang, Hui
p. 6591 - 6597
(2021/09/10)

Sequential Ir/Cu-Mediated Method for the Meta-Selective C-H Radiofluorination of (Hetero)Arenes
This article describes a sequential Ir/Cu-mediated process for the meta-selective C-H radiofluorination of (hetero)arene substrates. In the first step, Ir-catalyzed C(sp2)-H borylation affords (hetero)aryl pinacolboronate (BPin) esters. The intermediate organoboronates are then directly subjected to copper-mediated radiofluorination with [18F]tetrabutylammonium fluoride to afford fluorine-18 labeled (hetero)arenes in high radiochemical yield and radiochemical purity. This entire process is performed on a benchtop without Schlenk or glovebox techniques and circumvents the need to isolate (hetero)aryl boronate esters. The reaction was automated on a TracerLab FXFN module with 1,3-dimethoxybenzene and a meta-tyrosine derivative. The products, [18F]1-fluoro-3,5-dimethoxybenzene and an 18F-labeled meta-tyrosine derivative, were obtained in 37 ± 5% isolated radiochemical yield and >99% radiochemical purity and 25% isolated radiochemical yield and 99% radiochemical purity, and 0.52 Ci/μmol (19.24 GBq/μmol) molar activity (Am), respectively.
Wright, Jay S.,Sharninghausen, Liam S.,Preshlock, Sean,Brooks, Allen F.,Sanford, Melanie S.,Scott, Peter J. H.
supporting information
p. 6915 - 6921
(2021/05/29)

Mild Copper-Catalyzed Addition of Arylboronic Esters to Di- tert -butyl Dicarbonate: An Easy Access to Methyl Arylcarboxylates
An efficient copper-catalyzed addition of arylboronic esters to (Boc) 2O was developed. The reaction can be conducted under exceedingly mild conditions and is compatible with a variety of synthetically relevant functional groups. It therefore represents a useful alternative route for the synthesis of methyl arylcarboxylates. A preliminary mechanistic study indicated the involvement of an addition-elimination mechanism.
Xu, Jin-Di,Su, Xiao-Bo,Wang, Cai,Yao, Li-Wei,Liu, Jing-Hui,Hu, Guo-Qin
supporting information
p. 833 - 837
(2021/02/26)

Method for preparing carboxylic ester compounds by oxidizing and breaking carbon-carbon bonds of secondary alcohol compounds
The invention discloses a method for preparing carboxylic ester compounds by oxidizing and breaking carbon-carbon bonds of secondary alcohol compounds. The method comprises the following steps: adding a secondary alcohol compound, an additive and a nitrogen-doped mesoporous carbon loaded monatomic catalyst into a fatty primary alcohol solvent, putting into a pressure container, sealing, introducing oxygen source gas with a certain pressure, controlling the pressure of the oxygen source gas to be 0.1-1 MPa and the reaction temperature to be 80-150 DEG C, and obtaining a product after the reaction to be the carboxylic ester compound. The nitrogen-doped mesoporous carbon-loaded monatomic catalyst adopted by the invention is high in activity, the highest separation yield of the carboxylic ester compound as a reaction product reaches 99%, the method is wide in application range, the reaction conditions are easy to control, the catalyst can be recycled, the post-treatment is simple, and the method is suitable for industrial production.
-
Paragraph 0052-0053; 0092

(2021/06/02)

Oxidative esterification of alcohols by a single-side organically decorated Anderson-type chrome-based catalyst
The direct esterification of alcohols with non-noble metal-based catalytic systems faces great challenges. Here, we report a new chrome-based catalyst stabilized by a single pentaerythritol decorated Anderson-type polyoxometalate, [N(C4H9)4]3[CrMo6O18(OH)3C{(OCH2)3CH2OH}], which can realize the efficient transformation from alcohols to esters by H2O2oxidation in good yields and high selectivity without extra organic ligands. A variety of alcohols with different functionalities including some natural products and pharmaceutical intermediates are tolerated in this system. The chrome-based catalyst can be recycled several times and still keep the original configuration and catalytic activity. We also propose a reasonable catalytic mechanism and prove the potential for industrial applications.
Wang, Jingjing,Jiang, Feng,Tao, Chaofu,Yu, Han,Ruhlmann, Laurent,Wei, Yongge
supporting information
p. 2652 - 2657
(2021/04/21)

The Highly Effective Cobalt Based Metal–Organic Frameworks Catalyst for One Pot Oxidative Esterification Under Mild Conditions
The cobalt-based metal organic frameworks (Co-MOFs) catalyst has been prepared with using terephthalic acid and 4,4′-bipyridine as organic linkers by facile solvothermal method for one pot oxidative esterification. The prepared catalyst was pyrolysed at different temperature and then applied for oxidation of aldehyde using molecular oxygen as benign oxidant under mild conditions. The Co-MOFs pyrolysed at 800?°C (denoted as Co-MOFs-800) catalyst exhibited excellent catalytic activity, selectivity and recyclability toward the oxidative esterification of benzaldehydes. Furthermore, it can be reused up to 5 runs without significant loss of activity. Graphic Abstract: [Figure not available: see fulltext.]
Chindawong, Chakkresit,Mekrattanachai, Pagasukon,Setthaya, Naruemon,Song, Wei Guo,Zhu, Lei
(2021/08/03)

Androgen receptor inhibitor and application thereof
The invention relates to the field of pharmacy, and particularly discloses an androgen receptor (AR) regulator combined with E3 ubiquitin ligase ligand or a salt thereof. Isomer and contains their pharmaceutical compositions.
-
Paragraph 0273-0276

(2021/11/10)

Antibacterial and Antiviral Activities of 1,3,4-Oxadiazole Thioether 4H-Chromen-4-one Derivatives
Various 1,3,4-oxadiazole thioether 4H-chromen-4-one derivatives were conceived. The title compounds demonstrated striking inhibitory effects againstXac,Psa, andXoo. EC50data exhibited that A8 (19.7 μg/mL) had better antibacterial activity againstXoothan myricetin, BT, and TC. Simultaneously, the mechanism of action of A8 had been verified by SEM. The results of anti-tobacco mosaic virus indicated that A9 had the bestin vivoantiviral effect compared with ningnanmycin. From the data of MST, it could be seen that A9 (0.003 ± 0.001 μmol/L) exhibited a strong binding capacity, which was far superior to ningnanmycin (2.726 ± 1.301 μmol/L). This study shows that the 1,3,4-oxadiazole thioether 4H-chromen-4-one derivatives may become agricultural drugs with great potential.
Cao, Xiao,Liu, Fang,Liu, Liwei,Liu, Tingting,Peng, Feng,Wang, Qifan,Xie, Chengwei,Xue, Wei,Yang, Jinsong
p. 11085 - 11094
(2021/10/01)

GPR52 Antagonist Reduces Huntingtin Levels and Ameliorates Huntington's Disease-Related Phenotypes
GPR52 is an orphan G protein-coupled receptor (GPCR) that has been recently implicated as a potential drug target of Huntington's disease (HD), an incurable monogenic neurodegenerative disorder. In this research, we found that striatal knockdown of GPR52 reduces mHTT levels in adult HdhQ140 mice, validating GPR52 as an HD target. In addition, we discovered a highly potent and specific GPR52 antagonist Comp-43 with an IC50 value of 0.63 μM by a structure-activity relationship (SAR) study. Further studies showed that Comp-43 reduces mHTT levels by targeting GPR52 and promotes survival of mouse primary striatal neurons. Moreover, in vivo study showed that Comp-43 not only reduces mHTT levels but also rescues HD-related phenotypes in HdhQ140 mice. Taken together, our study confirms that inhibition of GPR52 is a promising strategy for HD therapy, and the GPR52 antagonist Comp-43 might serve as a lead compound for further investigation.
Wang, Congcong,Zhang, Yu-Fang,Guo, Shimeng,Zhao, Quan,Zeng, Yanping,Xie, Zhicheng,Xie, Xin,Lu, Boxun,Hu, Youhong
p. 941 - 957
(2020/11/30)

Ruthenium-Catalyzed Three-Component Alkylation: A Tandem Approach to the Synthesis of Nonsymmetric N,N-Dialkyl Acyl Hydrazides with Alcohols
The borrowing hydrogen strategy has been applied in the synthesis of nonsymmetric N,N-dialkylated acyl hydrazides via a tandem three-component reaction catalyzed by a phosphine free diaminocyclopentadienone ruthenium tricarbonyl complex. This strategy represents the first direct one-pot approach to nonsymmetric functionalized acyl hydrazides. Different aromatic acyl hydrazides underwent dialkylation with a variety of primary or secondary alcohols and methanol or ethanol as alkylating agents in mild reaction conditions and good yields. Deuterium labelling experiments suggested that the primary or secondary alcohol was the hydrogen source in this tandem process. DFT calculations show that the combination of the tandem mixed product cannot be perfectly explained neither structurally nor electronically, but might be dependent of the physical state of the aldehyde or ketone intermediate (gaz vs. liquid) at the reaction temperature. (Figure presented.).
Bettoni, Léo,Joly, Nicolas,Lohier, Jean-Fran?ois,Gaillard, Sylvain,Poater, Albert,Renaud, Jean-Luc
supporting information
p. 4009 - 4017
(2021/07/02)

Hydrogen Bond Directed Photocatalytic Hydrodefluorination and Methods of Use Thereof
Methods of synthesizing compounds comprising fluorinated aryl groups are disclosed, wherein said methods utilize hydrogen bond directed photocatalytic hydrodefluorination.
-
(2021/01/22)

Nickel-catalyzed carbonylation of secondary trifluoromethylated, difluoromethylated, and nonfluorinated aliphatic electrophiles with arylboronic acids under 1 atm of co
The nickel-catalyzed carbonylation of aliphatic electrophiles with the most straightforward CO remains challenging. Here, we describe an example of the nickel-catalyzed carbonylation of secondary alkyl halides with arylboronic acids under 1 atm of CO. The reaction exhibits high functional group tolerance and a broad substrate scope, including trifluoromethylated, difluoromethylated, and difluoroacetylated secondary alkyl iodides and secondary benzyl bromides, providing a general and cost-efficient method to access alkyl ketones, especially α-trifluoromethylated alkyl ketones that are of great interest in medicinal chemistry. Preliminary mechanistic studies reveal that a bimetallic oxidative addition is likely involved in the reaction.
Cheng, Ran,Zhao, Hai-Yang,Zhang, Shu,Zhang, Xingang
p. 36 - 42
(2019/12/11)

Palladium-Catalyzed Chlorocarbonylation of Aryl (Pseudo)Halides Through In Situ Generation of Carbon Monoxide
An efficient palladium-catalyzed chlorocarbonylation of aryl (pseudo)halides that gives access to a wide range of carboxylic acid derivatives has been developed. The use of butyryl chloride as a combined CO and Cl source eludes the need for toxic, gaseous carbon monoxide, thus facilitating the synthesis of high-value products from readily available aryl (pseudo)halides. The combination of palladium(0), Xantphos, and an amine base is essential to promote this broadly applicable catalytic reaction. Overall, this reaction provides access to a great variety of carbonyl-containing products through in situ transformation of the generated aroyl chloride. Combined experimental and computational studies support a reaction mechanism involving in situ generation of CO.
Bismuto, Alessandro,Boehm, Philip,Morandi, Bill,Roediger, Sven
supporting information
p. 17887 - 17896
(2020/08/19)

Cobalt Nanoparticles-Catalyzed Widely Applicable Successive C?C Bond Cleavage in Alcohols to Access Esters
Selective cleavage and functionalization of C?C bonds have important applications in organic synthesis and biomass utilization. However, functionalization of C?C bonds by controlled cleavage remains difficult and challenging because they are inert. Herein, we describe an unprecedented efficient protocol for the breaking of successive C?C bonds in alcohols to form esters with one or multiple carbon atoms less using heterogeneous cobalt nanoparticles as catalyst with dioxygen as the oxidant. A wide range of alcohols including inactive long-chain alkyl aryl alcohols undergo smoothly successive cleavage of adjacent ?(C?C)n? bonds to afford the corresponding esters. The catalyst was used for seven times without any decrease in activity. Characterization and control experiments disclose that cobalt nanoparticles are responsible for the successive cleavage of C?C bonds to achieve excellent catalytic activity, while the presence of Co-Nx has just the opposite effect. Preliminary mechanistic studies reveal that a tandem sequence reaction is involved in this process.
Dai, Wen,Gao, Shuang,Li, Guosong,Luo, Huihui,Lv, Ying,Shang, Sensen,Wang, Lianyue
supporting information
p. 19268 - 19274
(2020/08/26)

Catalytic conversion of ketones to esters: Via C(O)-C bond cleavage under transition-metal free conditions
The catalytic conversion of ketones to esters via C(O)-C bond cleavage under transition-metal free conditions is reported. This catalytic process proceeds under solvent-free conditions and offers an easy operational procedure, broad substrate scope with excellent selectivity, and reaction scalability. This journal is
Subaramanian, Murugan,Ramar, Palmurukan M.,Rana, Jagannath,Gupta, Virendra Kumar,Balaraman, Ekambaram
supporting information
p. 8143 - 8146
(2020/09/09)

Ruthenium-catalyzed hydrogenation of CO2as a route to methyl esters for use as biofuels or fine chemicals
A novel robust diphosphine-ruthenium(ii) complex has been developed that can efficiently catalyze both the hydrogenation of CO2 to methanol and its in situ condensation with carboxylic acids to form methyl esters; a TON of up to 3260 is achievable for the CO2 to methanol step. Both aromatic and aliphatic carboxylic acids can be transformed to their corresponding methyl esters with high conversion and selectivity (17 aliphatic and 18 aromatic examples). On the basis of a series of experiments, a mechanism has been proposed to account for the various steps involved in the catalytic pathway. More importantly, this approach provides a promising route for using CO2 as a C1 source for the production of biofuels, fine chemicals and methanol.
Li, Yong,Liu, Qingbin,Ma, Yanping,Solan, Gregory A.,Sun, Wen-Hua,Wang, Zheng,Zhang, Qiuyue,Zhao, Ziwei,Zhong, Yanxia
p. 6766 - 6774
(2020/08/25)

Methoxylation of Acyl Fluorides with Tris(2,4,6-trimethoxyphenyl)phosphine via C-OMe Bond Cleavage under Metal-Free Conditions
Acyl fluorides are subjected to methoxylation with tris(2,4,6-trimethoxyphenyl)phosphine (TMPP) to afford the corresponding methyl esters in good to excellent yields. This transformation is featured by C(sp2)-OMe bond cleavage under metal-free conditions. Unprecedented utilization of TMPP as a methoxylating agent realized the installation of an OMe group into the desired products.
Ishida, Takumi,Nishihara, Yasushi,Wang, Xiu,Wang, Zhenhua
p. 7526 - 7533
(2020/06/27)

Palladium-Catalyzed, Copper(I)-Promoted Methoxycarbonylation of Arylboronic Acids with O-Methyl S-Aryl Thiocarbonates
Here, we report O-methyl S-aryl thiocarbonates as a versatile esterification reagent for palladium-catalyzed methoxycarbonylation of arylboronic acid in the presence of copper(I) thiophene-2-carboxylate (CuTC). The reaction condition is mild, and a variety of substituents including sensitive-Cl,-Br, and free-NH2 could be tolerated. Further applications in the late-stage esterification of some pharmaceutical drugs demonstrate the broad utility of this method.
Cao, Ya-Fang,Li, Ling-Jun,Liu, Min,Xu, Hui,Dai, Hui-Xiong
p. 4475 - 4481
(2020/04/10)

Ni-catalyzed direct alcoholysis of N-acylpyrrole-type tertiary amides under mild conditions
N-Acylpyrrole-type amides are a class of versatile building blocks in asymmetric synthesis. We report that by employing Ni(COD)2/2,2′-bipyridine (5 mol%) catalytic system, the direct, catalytic alcoholysis of N-acylpyrrole-type aromatic and aliphatic amides with both primary and secondary alcohols can be achieved efficiently under very mild conditions (rt, 1 h) even at gram scale. By increasing the catalyst loading to 10 mol%, prolonging reaction time (18 h), and/or elevating reaction temperature to 50 °C/80 °C, the reaction could be extended to both complex and hindered N-acylpyrroles as well as to N-acylpyrazoles, Nacylindoles, and to other (functionalized) primary and secondary alcohols. In all cases, only 1.5 equiv. of alcohol were used. The value of the method has been demonstrated by the racemization-free, catalytic alcoholysis of chiral amides yielded from other asymmetric methodologies.
Chen, Hang,Chen, Dong-Huang,Huang, Pei-Qiang
p. 370 - 376
(2020/03/03)

Nickel-Catalyzed Esterification of Amides Under Mild Conditions
Abstract: The use of ligands to adjust the catalytic activity of the catalyst for esterification of amides is challenge in organic chemistry. In this paper, Nickel(II)-NHC-catalyzed the esterification reaction between N,N-di-Boc amide and alcohols at room temperature have been demonstrated. The imidazolium salt bearing a hydroxyl functionalized side arm showed high effective catalytic activity in the activation of the amide N–C bond in air atmosphere. Graphic Abstract: [Figure not available: see fulltext.].
Li, Jun-Fei,Wang, Yao-Fang,Wu, Yuan-Yuan,Liu, Wen-Jing,Wang, Jun-Wen
p. 874 - 880
(2019/11/13)

Palladium-catalyzed aryloxy- and alkoxycarbonylation of aromatic iodides in γ-valerolactone as bio-based solvent
Fossil-based solvents and triethylamine as a toxic and volatile base were successfully replaced with γ-valerolactone as a non-volatile solvent and K2CO3 as inorganic base in the alkoxy- and aryloxycarbonylation of aryl iodides using phosphine-free Pd catalyst systems. By this, the traditional systems were not simply replaced but also significantly improved. In the study, the effects of different reaction parameters, i.e. the use of several other solvents, the temperature, the carbon monoxide pressure, the base and the catalyst concentrations, were evaluated in details on the efficiency of the carbonylations. To gather some information on the mechanism of these reactions, the effects of the electronic parameters (σ) of various aromatic substituents of the aryl iodides as well as the influence of para-substitution of phenol were investigated on the activity. For a comparison, the aryl-substituted aryl iodides were also reacted with methanol and aryl iodide was also alkoxycarbonylated using several different lower alcohols. From the observed correlations between the electronic parameters of the aromatic substituents and the rates, it appears that the rate determining step is the oxidative addition of Ar–I to Pd0, provided that sufficient amounts of nucleophiles are present for the ester formation. If this is not the case, the rate of nucleophile attack might determine the overall rate.
Tukacs, József M.,Marton, Bálint,Albert, Eszter,Tóth, Imre,Mika, László T.
(2020/08/11)

Synthesis of Some Aromatic and Aliphatic Esters Using WO3/ZrO2 Solid Acid Catalyst under Solvent Free Conditions
A simple method is delineated for the synthesis of substituted ester products in superior yields by esterification reaction under solvent unbound condition using tungsten upgraded ZrO2 solid acid catalyst at 353 K. The WO3/ZrO2 catalyst has been prepared by using impregnation method followed by calcination at 923 K over a period of 6 h in air atmosphere. SEM, XRD, FTIR, and BET surface area techniques were used to categorize this catalyst. Zirconia has both acidic and basic possessions which can be changed by incorporating suitable promoter atom like tungsten which in turn increases the surface area thereby enhancing the surface acidity. Impregnation of W6+ ions exhibits a strong influence on phase modification of zirconia from thermodynamically solid monoclinic to metastable tetragonal phase. Amalgamation of promoter W6+ will stabilize tetragonal phase which is active in catalyzing reactions. In esterification reaction WO3/ZrO2 catalyst was found to be stable, efficient and environmental friendly, effortlessly recovered by filtration, excellent yield of product and can be reusable efficiently.
Guguloth, Vijaya Charan,Battu, Satyanarayana
p. 2153 - 2157
(2020/09/16)

Synthesis and trypanocidal activity of novel pyridinyl-1,3,4-thiadiazole derivatives
Herein, we present the design, synthesis and trypanocidal evaluation of sixteen new 1,3,4-thiadiazole derivatives from N-aminobenzyl or N-arylhydrazone series. All derivatives were assayed against the trypomastigote form of Trypanosoma cruzi, showing IC50 values ranging from 3 to 226 μM, and a better trypanocidal profile was demonstrated for the 1,3,4-thiadiazole-N-arylhydrazones (3a-g). In this series, the 2-pyridinyl fragment bound to the imine subunit of the hydrazine moiety presented pharmacophoric behavior for trypanocidal activity. Compounds 2a, 11a and 3e presented remarkable activity and excellent selectivity indexes. Compound 2a was also active against the intracellular amastigote form of T. cruzi. Moreover, its corresponding hydrochloride, compound 11a, showed the most promising profile, producing phenotypic changes similar to those caused by posaconazole, a well-known inhibitor of sterol biosynthesis. Thus, 1,3,4-thiadiazole derivative 11a could be considered a good prototype for the development of new drug candidates for Chagas disease therapy.
Barbosa, Juliana M. C.,Bernardino, Patrícia,Decoté-Ricardo, Débora,Fraga, Carlos A. M.,Freitas, Rosana H. C. N.,Melo, Tatiana G.,Salom?o, Kelly,Sueth-Santiago, Vitor,Wardell, James L.,Wardell, Solange M. S. V.,da Silva, Edson F.
(2020/05/13)

Synthesis, biological evaluation of benzothiazole derivatives bearing a 1,3,4-oxadiazole moiety as potential anti-oxidant and anti-inflammatory agents
Twenty benzothiazole derivatives bearing a 1,3,4-oxadiazole moiety were synthesized and evaluated for their anti-oxidant and anti-inflammatory activities. Among these compounds, 8h and 8l were appeared to have high radical scavenging efficacies as 0.05 ± 0.02 and 0.07 ± 0.03 mmol/L of IC50 values in ABTS+[rad] bioassay, respectively. In anti-inflammatory tests, compound 8h displayed good activity with 57.35% inhibition after intraperitoneal administration, which was more potent than the reference drug (indomethacin). Molecular modeling studies were performed to investigate the binding mode of the representative compound 8h into COX-2 enzyme. In vitro enzyme study implied that compound 8h exerted its anti-inflammatory activity through COX-2 inhibition.
Bai, Xue-Qian,Cui, Ming-Yue,Li, Chun-Shi,Liang, Cheng-Wu,Song, Ze-Wen,Wang, Hui-Yan,Zhang, Tian-Yi,Zheng, Xian-Jing
(2020/05/08)

Synthesis, crystal structures, computational studies and α-amylase inhibition of three novel 1,3,4-oxadiazole derivatives
Oxadiazoles have broad range of biological applications and have been investigated widely by the scientific community. In this study, we report the synthesis, X-ray diffraction, density functional theory (DFT) and α-amylase inhibition activities of three 1,3,4-oxadiazole derivatives (1–3). The compounds are synthesized in good yields (70–83%) and their structures are confirmed through different spectro-analytical techniques and single crystal X-ray diffraction. Density functional theory (DFT) calculations are performed to validate not only X-ray results, but also to investigate the dispersion of charges and reactivity through frontier molecular orbitals and molecular electrostatic potential (MEP) analyses. α-Amylase inhibition assay is performed in order to find out the enzyme inhibitory potential of the synthesized compounds (1–3). The low IC50 value (86.83 ± 0.23 μg/mL) of compound 2 reflects the potential α-amylase inhibitory activity of the compound as compared to others.
Hamdani, Syeda Shamila,Khan, Bilal Ahmad,Ahmed, Muhammad Naeem,Hameed, Shahid,Akhter, Kulsoom,Ayub, Khurshid,Mahmood, Tariq
(2019/09/30)

Discovery of [1,2,4]triazole derivatives as new metallo-β-lactamase inhibitors
The emergence and spread of metallo-β-lactamase (MBL)-mediated resistance to β-lactam antibacterials has already threatened the global public health. A clinically useful MBL inhibitor that can reverse β-lactam resistance has not been established yet. We here report a series of [1,2,4]triazole derivatives and analogs, which displayed inhibition to the clinically relevant subclass B1 (Verona integron-encoded MBL-2) VIM-2. 3-(4-Bromophenyl)-6,7-dihydro-5H-[1,2,4]triazolo [3,4-b][1,3]thiazine (5l) manifested the most potent inhibition with an IC50 (half-maximal inhibitory concentration) value of 38.36 μM. Investigations of 5l against other B1 MBLs and the serine β-lactamases (SBLs) revealed the selectivity to VIM-2. Molecular docking analyses suggested that 5l bound to the VIM-2 active site via the triazole involving zinc coordination and made hydrophobic interactions with the residues Phe61 and Tyr67 on the flexible L1 loop. This work provided new triazole-based MBL inhibitors and may aid efforts to develop new types of inhibitors combating MBL-mediated resistance.
Yuan, Chen,Yan, Jie,Song, Chen,Yang, Fan,Li, Chao,Wang, Cheng,Su, Huiling,Chen, Wei,Wang, Lijiao,Wang, Zhouyu,Qian, Shan,Yang, Lingling
(2020/01/11)

TEMPO-Me: An Electrochemically Activated Methylating Agent
Bench- and air-stable 1-methoxy-2,2,6,6-tetramethylpiperidine (TEMPO-Me) is relatively unreactive at ambient temperature in the absence of an electrochemical stimulus. In this report, we demonstrate that the one-electron electrochemical oxidation of TEMPO-Me produces a powerful electrophilic methylating agent in situ. Our computational and experimental studies are consistent with methylation proceeding via a SN2 mechanism, with a strength comparable to the trimethyloxonium cation. A protocol is developed for the electrochemical methylation of aromatic acids using TEMPO-Me.
Norcott, Philip L.,Hammill, Chelsey L.,Noble, Benjamin B.,Robertson, Johnathon C.,Olding, Angus,Bissember, Alex C.,Coote, Michelle L.
supporting information
p. 15450 - 15455
(2019/11/02)

Palladium-Catalyzed Visible-Light-Driven Carboxylation of Aryl and Alkenyl Triflates by Using Photoredox Catalysts
A visible-light-driven carboxylation of aryl and alkenyl triflates with CO2 is developed by using a combination of Pd and photoredox catalysts. This reaction proceeds under mild conditions and can be applied to a wide range of substrates including acyclic alkenyl triflates.
Shimomaki, Katsuya,Nakajima, Tomoya,Caner, Joaquim,Toriumi, Naoyuki,Iwasawa, Nobuharu
p. 4486 - 4489
(2019/06/24)

Cobalt Nanoparticles Embedded in N-Doped Porous Carbon Derived from Bimetallic Zeolitic Imidazolate Frameworks for One-Pot Selective Oxidative Depolymerization of Lignin
Cobalt nanoparticles embedded in N-doped porous carbon (Co@CN) were prepared by the pyrolysis of bimetallic zeolitic imidazolate frameworks (BMZIFs) based on ZIF-8 and ZIF-67. The catalyst shows excellent catalytic efficiency in one-pot selective oxidative cleavage of different linkages like β-O-4, a-O-4 and β-1 in organosolv lignin and lignin model compounds in the presence of oxygen (ambient pressure) under mild conditions (383 K). Compared with traditional supported catalyst, the catalyst gives a highly hollow structure, which favored the adsorption of substrates and oxygen. The uniform cobalt nanoparticles surrounded by N-doped graphitic structures and the strong electron transfer from graphitic nitrogen to Co NPs make it hard to be oxidized prior to use and higher catalytic reactivity. Moreover, the catalyst can be easily recovered by magnetic force after the reaction, and reused after reduction for five times without an obvious change in yields.
Sun, Kangkang,Chen, Shujie,Zhang, Jiawei,Lu, Guo-Ping,Cai, Chun
p. 1264 - 1271
(2019/02/01)

Efficient and Recyclable RuCl3 ? 3H2O Catalyst Modified with Ionic Diphosphine for the Alkoxycarbonylation of Aryl Halides
A series of ionic (mono-/di-)phosphines (L2, L4, and L6) with structural similarity and their corresponding neutral counterparts (L1, L3, and L5) were applied to modulate the catalytic performance of RuCl3 ? 3H2O. With the involvement of the ionic diphosphine (L4), in which the two phosphino-fragments were linked by butylene group, RuCl3 ? 3H2O with advantages of low cost, robustness, and good availability was found to be an efficient and recyclable catalyst for the alkoxycarbonylation of aryl halides. The L4-based RuCl3 ? 3H2O system corresponded to the best conversion of PhI (96 %) along with 99 % selectivity to the target product of methyl benzoate as well as the good generality to alkoxycarbonylation of different aryl halides (ArX, X=I and Br) with alcohols MeOH, EtOH, i-PrOH and n-BuOH. The electronic and steric effects of the applied phosphines, which were analyzed by the 31P NMR for 1J31P-77Se1J measurement and single-crystal X-ray diffraction, were carefully co-related to the performance RuCl3 ? 3H2O catalyst. In addition, the L4-based RuCl3 ? 3H2O system could be recycled successfully for at least eight runs in the ionic liquid [Bmim]PF6.
Zhou, Qing,Liu, Lei,Guo, Wen-Di,Liang, Wen-Yu,Lu, Yong,Liu, Ye
p. 166 - 172
(2019/02/01)

Dehydrogenative cross-coupling of primary alcohols to form cross-esters catalyzed by a manganese pincer complex
Base-metal-catalyzed dehydrogenative cross-coupling of primary alcohols to form cross-esters as major products, liberating hydrogen gas, is reported. The reaction is catalyzed by a pincer complex of earth-abundant manganese in the presence of catalytic base, without any hydrogen acceptor or oxidant. Mechanistic insight indicates that a dearomatized complex is the actual catalyst, and indeed this independently prepared dearomatized complex catalyzes the reaction under neutral conditions.
Das, Uttam Kumar,Ben-David, Yehoshoa,Leitus, Gregory,Diskin-Posner, Yael,Milstein, David
p. 479 - 484
(2019/01/11)

Pd-Colloids-Catalyzed/Ag2O-Oxidized General and Selective Esterification of Benzylic Alcohols
Palladium colloids obtained from the degradation of Hermann–Beller palladacycle proved to be an efficient catalytic system in combination with silver oxide as a selective oxidant for the oxidative esterification of differently substituted benzyl alcohols in MeOH as solvent. Excellent reactivity exhibited by the catalytic system also allowed the alcoholic coupling partner to be changed from MeOH to a wide range of alcohols having diverse functionalities. The mildness of the developed protocol also made it possible to employ propargyl alcohol as the coupling partner without any observation of any interference of the terminal alkyne. Selective oxidative coupling of a primary alcoholic functional group over secondary in the case of glycols and glycerols was also made possible using the developed catalyst system. To test the relevancy of Pd/Ag combined catalysis mixed Pd/Ag colloids were synthesized, characterized by TEM, XRD and XPS and applied to oxidative-esterification successfully.
Sable, Vaibhav,Shah, Jagrut,Sharma, Anuja,Kapdi, Anant R.
supporting information
p. 2639 - 2647
(2019/07/08)

Aldehyde effect and ligand discovery in Ru-catalyzed dehydrogenative cross-coupling of alcohols to esters
The presence of different aldehydes is found to have a significant influence on the catalytic performance when using PN(H)P type ligands for dehydrogenation of alcohols. Accordingly, hybrid multi-dentate ligands were discovered based on an oxygen-transfer alkylation of PNP ligands by aldehydes. The relevant Ru-PNN(PO) system provided the desired unsymmetrical esters in good yields via acceptorless dehydrogenation of alcohols. Hydrogen bonding interactions between the phosphine oxide moieties and alcohol substrates likely assisted the observed high chemoselectivity.
Jiang, Xiaolin,Zhang, Jiahui,Zhao, Dongmei,Li, Yuehui
p. 2797 - 2800
(2019/03/27)

Chloride-Induced Highly Active Au Catalyst for Methyl Esterification of Alcohols
Chloride is generally regarded as a harmful species for the heterogeneous catalysts, especially Au catalysts. In this work, a series of active Au/NiOx catalysts were successfully prepared with co-precipitation method by tracking the concentrations of chloride in the re-dispersed aqueous solutions. For methyl esterification of alcohols, the highest active Au/NiOx catalysts could be prepared from aqueous solutions containing 8-13 ppm chloride, the yield of methyl benzoate of catalyst Au/NiOx-9 was 99%. The catalyst structures and the role of chloride in catalysts were explored by ICP, BET, XPS, TEM and EXAFS characterizations. It was found that the appropriate amount of residual chloride in Au catalysts was beneficial to their catalytic activities. Especially for Au/NiOx-9, the appropriate amount of residual chloride had positive effects on the physicochemical properties of Au/NiOx catalyst, the position of Au nanoparticles (NPs) located on NiOx crystallites and the ratio of Auδ+/Au0 in catalyst, which together resulted in its high reactivity.
Zhang, Chengming,Wang, Yongzhao
p. 249 - 254
(2019/02/13)

Aldehydes as potential acylating reagents for oxidative esterification by inorganic ligand-supported iron catalysis
The oxidative esterification of various aldehydes with alcohols could be achieved by a heterogeneous iron(iii) catalyst supported on a ring-like POM inorganic ligand under mild conditions, affording the corresponding esters, including several drug molecules and natural products, in high yields. ESI-MS and control experiments demonstrated that POM-FeV(O) was the active catalytic species and the plausible mechanism was presented. More importantly, the 6th run of the iron catalyst recycles shows only a slight decrease in the yield.
Yu, Han,Wang, Jingjing,Wu, Zhikang,Zhao, Qixin,Dan, Demin,Han, Sheng,Tang, Jiangjiang,Wei, Yongge
supporting information
p. 4550 - 4554
(2019/08/21)

1,3-Dibromo-5,5-dimethylhydantoin as a Precatalyst for Activation of Carbonyl Functionality
Activation of carbonyl moiety is one of the most rudimentary approaches in organic synthesis and is crucial for a plethora of industrial-scale condensation reactions. In esterification and aldol condensation, which represent two of the most important reactions, the susceptibility of the carbonyl group to nucleophile attack allows the construction of a variety of useful organic compounds. In this context, there is a constant need for development of and improvement in the methods for addition-elimination reactions via activation of carbonyl functionality. In this paper, an advanced methodology for the direct esterification of carboxylic acids and alcohols, and for aldol condensation of aldehydes using widely available, inexpensive, and metal-free 1,3-dibromo-5,5-dimethylhydantoin under neat reaction conditions is reported. The method is air- and moisture-tolerant, allowing simple synthetic and isolation procedures for both reactions presented in this paper. The reaction pathway for esterification is proposed and a scale-up of certain industrially important derivatives is performed.
?ebular, Klara,Bo?i?, Bojan ?.,Stavber, Stojan
supporting information

(2019/08/01)

Synthesis and biological activities of benzothiazole derivatives bearing a 1,3,4-thiadiazole moiety
A series of benzothiazole derivatives bearing a 1,3,4-thiadiazole moiety were designed, synthesized and evaluated for their antibacterial, antifungal and antiviral activities. The bioassay results indicated that most of target compounds showed good antiviral activities against tobacco mosaic virus (TMV) and antibacterial activities against Xanthomonas oryzae pv. oryzae (Xoo) and Ralstonia solanacearum (Rs). Especially, the anti-Xoo effect of title compounds 5k (N-(5-methoxybenzo[d]thiazol-2-yl)-2-((5-(2-tolyl)-1,3,4-thiadiazol-2-yl)thio)acetamide) and the anti-Rs effect of title compounds 5a (N-(5-nitrobenzo[d]thiazol-2-yl)-2-((5-(4-(trifluorom ethyl)phenyl)-1,3,4-thiadiazol-2-yl)thio)acetmide) respectively reached 52.4% and 71.6% at 100 μg/mL, which are superior to that of bismerthiazol (32.0% and 52.3%). In addition, the protective and inactivation activities of title compound 5i (N-(5-methoxybenzo [d]thiazol-2-yl)-2-((5-(4-nitrophenyl)-1,3,4-thiadiazol-2-yl)thio)acetamide) against TMV were 79.5% and 88.3%, respectively, which are better than that of ningnanmycin (76.4% and 86.8%). The above research showed that benzothiazole derivatives bearing a 1,3,4-thiadiazole moiety may be used as potential molecular templates in searching for highly-efficient antiviral and antibacterial agents.
Tang, Xu,Wang, Zhongbo,Zhong, Xinmin,Wang, Xiaobin,Chen, Lijuan,He, Ming,Xue, Wei
p. 241 - 248
(2019/01/04)

SAR Studies on Aromatic Acylhydrazone-Based Inhibitors of Fungal Sphingolipid Synthesis as Next-Generation Antifungal Agents
Recently, the fungal sphingolipid glucosylceramide (GlcCer) synthesis has emerged as a highly promising new target for drug discovery of next-generation antifungal agents, and we found two aromatic acylhydrazones as effective inhibitors of GlcCer synthesis based on HTP screening. In the present work, we have designed libraries of new aromatic acylhydrazones, evaluated their antifungal activities (MIC80 and time-kill profile) against C. neoformans, and performed an extensive SAR study, which led to the identification of five promising lead compounds, exhibiting excellent fungicidal activities with very large selectivity index. Moreover, two compounds demonstrated broad spectrum antifungal activity against six other clinically relevant fungal strains. These five lead compounds were examined for their synergism/cooperativity with five clinical drugs against seven fungal strains, and very encouraging results were obtained; e.g., the combination of all five lead compounds with voriconazole exhibited either synergistic or additive effect to all seven fungal strains.
Del Poeta, Maurizio,Haranahalli, Krupanandan,Lazzarini, Cristina,Mallamo, John,McCarthy, J. Brian,Ojima, Iwao,Pathiranage, Senuri,Sun, Yi,Zambito, Julia
(2019/09/06)

LIT-001, the First Nonpeptide Oxytocin Receptor Agonist that Improves Social Interaction in a Mouse Model of Autism
Oxytocin (OT) and its receptor (OT-R) are implicated in the etiology of autism spectrum disorders (ASD), and OT-R is a potential target for therapeutic intervention. Very few nonpeptide oxytocin agonists have currently been reported. Their molecular and in vivo pharmacology remain to be clarified, and none of them has been shown to be efficient in improving social interaction in animal models relevant to ASD. In an attempt to rationalize the design of centrally active nonpeptide full agonists, we studied in a systematic way the structural determinants of the affinity and efficacy of representative ligands of the V1a and V2 vasopressin receptor subtypes (V1a-R and V2-R) and of the oxytocin receptor. Our results confirm the subtlety of the structure-affinity and structure-efficacy relationships around vasopressin/oxytocin receptor ligands and lead however to the first nonpeptide OT receptor agonist active in a mouse model of ASD after peripheral ip administration.
Frantz, Marie-Céline,Pellissier, Lucie P.,Pflimlin, Elsa,Loison, Stéphanie,Gandiá, Jorge,Marsol, Claire,Durroux, Thierry,Mouillac, Bernard,Becker, Jér?me A. J.,Le Merrer, Julie,Valencia, Christel,Villa, Pascal,Bonnet, Dominique,Hibert, Marcel
supporting information
p. 8670 - 8692
(2018/10/05)

Method for catalyzing oxidative cracking of lignin by heterogeneous cobalt
The invention discloses a method for catalyzing oxidative cracking of lignin by a heterogeneous cobalt. The method adopts a porous carbon-nitrogen-loaded cobalt nano-material as a catalyst, and oxidative cracking of beta-O-4, alpha-O-4 and beta-1 lignin template compounds and solvent type lignin is carried out under the action of the catalyst with methanol as a solvent and oxygen as an oxidant inorder to obtain phenol, methyl benzoate and other small molecule compounds. The heterogeneous cobalt catalyst adopted in the invention realizes a wide application range of a substrate, is suitable forthe oxidative cracking of the beta-O-4, alpha-O-4 and beta-1 lignin template compounds and solvent type lignin, realizes high yield of a product and no polymerization of the product, and can be simply recovered through magnetic force after the reaction ends.
-
Paragraph 0024; 0025; 0026

(2018/11/26)

A biocatalytic method for the chemoselective aerobic oxidation of aldehydes to carboxylic acids
Herein, we present a study on the oxidation of aldehydes to carboxylic acids using three recombinant aldehyde dehydrogenases (ALDHs). The ALDHs were used in purified form with a nicotinamide oxidase (NOx), which recycles the catalytic NAD+ at the expense of dioxygen (air at atmospheric pressure). The reaction was studied also with lyophilised whole cell as well as resting cell biocatalysts for more convenient practical application. The optimised biocatalytic oxidation runs in phosphate buffer at pH 8.5 and at 40 °C. From a set of sixty-one aliphatic, aryl-Aliphatic, benzylic, hetero-Aromatic and bicyclic aldehydes, fifty were converted with elevated yield (up to >99%). The exceptions were a few ortho-substituted benzaldehydes, bicyclic heteroaromatic aldehydes and 2-phenylpropanal. In all cases, the expected carboxylic acid was shown to be the only product (>99% chemoselectivity). Other oxidisable functionalities within the same molecule (e.g. hydroxyl, alkene, and heteroaromatic nitrogen or sulphur atoms) remained untouched. The reaction was scaled for the oxidation of 5-(hydroxymethyl)furfural (2 g), a bio-based starting material, to afford 5-(hydroxymethyl)furoic acid in 61% isolated yield. The new biocatalytic method avoids the use of toxic or unsafe oxidants, strong acids or bases, or undesired solvents. It shows applicability across a wide range of substrates, and retains perfect chemoselectivity. Alternative oxidisable groups were not converted, and other classical side-reactions (e.g. halogenation of unsaturated functionalities, Dakin-Type oxidation) did not occur. In comparison to other established enzymatic methods such as the use of oxidases (where the concomitant oxidation of alcohols and aldehydes is common), ALDHs offer greatly improved selectivity.
Knaus, Tanja,Tseliou, Vasilis,Humphreys, Luke D.,Scrutton, Nigel S.,Mutti, Francesco G.
p. 3931 - 3943
(2018/09/11)

Superior performance of Co-N/m-C for direct oxidation of alcohols to esters under air
A convenient, expeditious, and high-efficiency protocol for the transformation of alcohols into esters using a Co-modified N-doped mesoporous carbon material (Co-N/m-C) as the catalyst is proposed. The catalyst was prepared through direct pyrolysis of a macromolecular precursor. The catalyst prepared using a pyrolysis temperature of 900 °C (labeled Co-N/m-C-900) exhibited the best performance. The strong coordination between the ultra-dispersed cobalt species and the pyridine nitrogen as well as the large area of the mesoporous surface resulted in a high turnover frequency value (107.6 mol methyl benzoate mol?1 Co h?1) for the direct aerobic oxidation of benzyl alcohol to methyl benzoate. This value is much higher than those of state-of-the-art transition-metal-based nanocatalysts reported in the literature. Moreover, the catalyst exhibited general applicability to various structurally diverse alcohols, including benzylic, allylic, and heterocyclic alcohols, achieving the target esters in high yields. In addition, a preliminary evaluation revealed that Co-N/m-C-900 can be used six times without significant activity loss. In general, the process was rapid, simple, and cost-effective.
Li, Ning,Shang, Sensen,Wang, Lianyue,Niu, Jingyang,Lv, Ying,Gao, Shuang
p. 1249 - 1257
(2018/06/14)

Microwave assisted synthesis and evaluation of some substituted 1,3,4-oxadiazoles as free radical scavenger
A series of 5-(4-substituted phenyl)-1,3,4-oxadiazoles (4a-h) were prepared from 4-substituted benzoic acid hydrazides (3a-h). Structures of the synthesized compounds were confirmed on the basis of IR, 13C NMR, Mass spectral methods and elemental analysis. The compounds were screened for antioxidant activities using hydrogen peroxide scavenging method comparing with ascorbic acid as standard antioxidant. The results reveal that the compounds possess significant free radical scavenging activities. It is recommended that these compounds might be used in future to generate derivatives for emerging free radical scavenger.
Upadhyay, Prabhat Kumar,Mishra, Pradeep
p. 661 - 666
(2020/07/02)

Synthesis and characterization of stable ZnO nanoparticles using imidazolium-based ionic liquids and their applications in esterification reaction
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
p. 1112 - 1120
(2018/09/21)

Esterification of aryl/alkyl acids catalysed by n-bromosuccinimide under mild reaction conditions
N-halosuccinimides (NXSs) are well-known to be convenient, easily manipulable and low-priced halogenation reagents in organic synthesis. In the present work, N-bromosuccinimide (NBS) has been promoted as the most efficient and selective catalyst among the NXSs in the reaction of direct esterification of aryl and alkyl carboxylic acids. Comprehensive esterification of substituted benzoic acids, mono-, di- and tri-carboxy alkyl derivatives has been performed under neat reaction conditions. The method is metal-free, air- and moisture-tolerant, allowing for a simple synthetic and isolation procedure as well as the large-scale synthesis of aromatic and alkyl esters with yields up to 100%. Protocol for the recycling of the catalyst has been proposed.
?ebular, Klara,Bo?i?, Bojan ?.,Stavber, Stojan
(2018/09/10)

Design, Synthesis and Evaluation of Antitubercular Activity of Novel 1,2,4-Triazoles Against MDR Strain of Mycobacterium tuberculosis
Emergence of various forms of resistant strains of Mycobacterium tuberculosis led to the exploration of drugs with novel mechanism of action. Recently econazole, an azole based antitubercular agent, attracted major attention for targeting mycobacterial cytochrome P450. In the present study, we designed novel 1,2,4-triazole derivatives based on econazole moiety and evaluated them for in vitro antitubercular activity against M. tuberculosis H37Rv and multi-drug resistant (MDR) strains of Mycobacterium.
Ganesh Kumar,Gautham Shenoy,Kar, Sidhartha Sankar,Shenoy, Vishnu,Bairy, Indira
p. 907 - 917
(2018/02/07)

Methyl group transfer upon gas phase decomposition of protonated methyl benzoate and similar compounds
Gas phase decompositions of protonated methyl benzoate and its conjugates have been studied by using electrospray ionization-collision induced dissociation-tandem mass spectrometry. Loss of CO2 molecule, thus transfer of methyl group, has been observed. In order to better understand this process, the theoretical calculations have been performed. For methyl benzoate conjugates, it has been found that position of substituent affects the loss of CO2 molecule, not the electron donor/withdrawing properties of the substituent. Therefore, electrospray ionization-mass spectrometry in positive ion mode may be useful for differentiation of isomers of methyl benzoate conjugates.
Frański, Rafa?,Gierczyk, B?a?ej,Zalas, Maciej,Jankowski, Wojciech,Hoffmann, Marcin
p. 379 - 384
(2018/05/14)