- Direct C–H Carboxylation Forming Polyfunctionalized Aromatic Carboxylic Acids by Combined Br?nsted Bases
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CO2 fixation into electron-deficient aromatic C–H bonds proceeds with the combined Br?nsted bases LiO-t-Bu and LiO-t-Am/CsF/18-crown-6 (t-Am = CEtMe2) under a CO2 atmosphere to afford a variety of polyfunctionalized aromat
- Hanasaka, Kazuya,Izumi, Koki,Kondo, Yoshinori,Kwon, Eunsang,Nozawa-Kumada, Kanako,Shigeno, Masanori,Tohara, Itsuki,Yamakoshi, Hiroyuki
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p. 809 - 814
(2022/02/05)
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- The Highly Effective Cobalt Based Metal–Organic Frameworks Catalyst for One Pot Oxidative Esterification Under Mild Conditions
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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
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- Nitration of aromatics with dinitrogen pentoxide in a liquefied 1,1,1,2-tetrafluoroethane medium
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Regardless of the sustainable development path, today, there are highly demanded chemical productions still operating that bear environmental and technological risks inherited from the previous century. The fabrication of nitro compounds, and nitroarenes in particular, is traditionally associated with acidic wastes formed in nitration reactions exploiting mixed acids. However, nitroarenes are indispensable for industrial and military applications. We faced the challenge and developed a greener, safer, and yet effective method for the production of nitroaromatics. The proposed approach comprises the application of an eco-friendly nitrating agent, namely dinitrogen pentoxide (DNP), in the medium of liquefied 1,1,1,2-tetrafluoroethane (TFE) - one of the most non-hazardous Freons. Importantly, the used TFE is not emitted into the atmosphere but is effortlessly recondensed and returned into the process. DNP is obtainedviathe oxidation of dinitrogen tetroxide with ozone. The elaborated method is characterized by high yields of the targeted nitro arenes, mild reaction conditions, and minimal amount of easy-to-utilize wastes.
- Fauziev, Ruslan V.,Kharchenko, Alexandr K.,Kuchurov, Ilya V.,Zharkov, Mikhail N.,Zlotin, Sergei G.
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p. 25841 - 25847
(2021/08/09)
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- Light-induced carboxylation of aryl derivatives with cooperative COF as an active photocatalyst and Ni(ii) co-catalyst
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The photocatalytic carboxylation of aryl derivatives was demonstrated under CO2at atmospheric pressure using a mesoporous covalent organic framework (COF) as the active photocatalyst with triethylamine (TEA) as a sacrificial electron source under visible light. A yield of greater than 91% of the isolated product was achieved with 5 mg of catalyst. The reaction cycle is dependent on the use of the Ni(dmg)2co-catalyst and the sacrificial electron donor (TEA). The reaction does not occur in the absence of light (445 nm) even at elevated reaction temperature. We have also demonstrated that a yield of 32% of the isolated product could be obtained with the use of sunlight in the catalytic cycle. Additionally, this heterogeneous catalytic system was recyclable and reusable for several cycles.
- Chakrabortty, Pekham,Das, Anjan,Chowdhury, Arpita Hazra,Ghosh, Swarbhanu,Khan, Aslam,Islam, Sk. Manirul
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p. 4738 - 4745
(2021/03/22)
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- Oxidative esterification of alcohols by a single-side organically decorated Anderson-type chrome-based catalyst
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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
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supporting information
p. 2652 - 2657
(2021/04/21)
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- COMPOUNDS AND METHODS FOR TREATING CANCER
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Substituted cinnamamide compounds and analogs, methods of making such compounds, pharmaceutical compositions and medicaments comprising such compounds, and methods of using such compounds to treat, prevent or ameliorate cancer are provided.
- -
-
Paragraph 0190; 0339-0341
(2020/12/19)
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- Synthesis, antifungal and antibacterial activity of calix[4]arene-based 1,3,4-oxadiazole derivatives
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We describe the synthesis of some novel p-tert-butylcalix[4]arene-based (5-aryl-1,3,4-oxadiazol-2-yl)2-chloroethanethioate derivatives (4a–e). These compounds were synthesized by the reaction of tetra-tert-butyl calix[4]arene (1) with (5-aryl-1,3,4-oxadiazol-2-yl)2-chloroethanethioate (3a–e) in the presence of potassium carbonate as a weak base and dry acetone as the solvent. All the newly synthesized calix[4]arene derivatives were characterized by elemental analysis and various spectroscopic methods such as FT-IR, 1H NMR,13C NMR, DEPT, and ESI-MS. The synthesized compounds were tested in vitro for their antibacterial and antifungal activities against Escherichia coli and Aspergillus fumigates in comparison with enrofloxacin and amphotericin as reference drugs, which are normally used for treating such infections. The synthesized compounds showed different inhibition zones against the tested bacteria and fungi. Compound 4c was found to be most effective against A. fumigates, whereas compound 4e was found to be equally effective against E. coli and A. fumigates.
- Dono Gezelbash, Zahra,Akbari Dilmaghani, Karim
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p. 1446 - 1452
(2020/03/11)
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- NITRATION
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The present invention relates to a process for preparing a nitrated compound, comprising the step of reacting a compound (A) comprising at least one substituted or unsubstituted aromatic or heteroaromatic ring, wherein said heteroaromatic ring comprises at least one heteroatom selected from the group consisting of oxygen, sulfur, phosphor, selenium and nitrogen, with a compound of formula (I) wherein Y is selected from the group consisting of hydrogen and nitro.
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Page/Page column 36; 37; 47; 66-67; 43; 49; 70
(2020/05/28)
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- 1,3-Dibromo-5,5-dimethylhydantoin as a Precatalyst for Activation of Carbonyl Functionality
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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
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supporting information
(2019/08/01)
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- Synthesis, characterization, and nonlinear optical properties of some new series of S-(5-aryl-1,3,4-oxadiazol-2-yl) 2-chloroethanethioate derivatives
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In the present investigation, some novel S-(5-aryl-1,3,4-oxadiazol-2-yl)2-chloroethanethioate (3a–3e) derivatives were synthesized and their impact on optical properties was studied. They have also been characterized by elemental analysis and various spectroscopic methods including FTIR, 1 H NMR, 13 C NMR, and UV-Vis techniques. The nonlinear refractive indexes of 3a–3e were also measured in dichloromethane via Z-scan method using a continuous wave diode-pumped laser at 532 nm wavelength. The nonlinear refractive coefficient of compounds was obtained from 1011 m2/W order. Regarding the appropriate nonlinearity of these compounds, they could be considered good candidates for biooptical and photonic applications. All the synthesized compounds (3a–3e) have also been evaluated for their antimicrobial and antifungal activities. The bioactive assay showed that the synthetic compounds displayed variable inhibition zones against tested bacterium Escherichia coli and fungus Aspergillus fumigatus in comparison to enrofloxacin and amphotericin as reference drugs, which are normally used for treating such infections.
- Ghezelbash, Zahra Dono,Motiei, Hamideh,Mahmoody, Miri,Dilmaghani, Karim Akbari
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p. 902 - 910
(2019/07/17)
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- Efficient and Recyclable RuCl3 ? 3H2O Catalyst Modified with Ionic Diphosphine for the Alkoxycarbonylation of Aryl Halides
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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
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p. 166 - 172
(2019/02/01)
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- Pd-Colloids-Catalyzed/Ag2O-Oxidized General and Selective Esterification of Benzylic Alcohols
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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.
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supporting information
p. 2639 - 2647
(2019/07/08)
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- Selective conversion of primary amides to esters promoted by KHSO4
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Primary amides, either aliphatic or aromatic, are easily converted to the corresponding esters via reflux in lower primary alcohols in the presence of KHSO4. Secondary amides lead to complicated mixtures under analogous conditions, whereastertiary amides were inert. Use of isopropyl alcohol resulted inthe formation of product atslower rate and lower yieldalong withside products, whereas, use of tertiary alcoholsdid not give successful conversion andallyl and benzyl alcohol provided complex mixtures.
- Sattenapally, Narsimha,Sharma, Jhanvi,Hou, Yuqing
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p. 174 - 183
(2018/09/10)
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- 2-Nitrobenzohydrazide as a potent urease inhibitor: Synthesis, characterization and single crystal X-ray diffraction analysis
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2-Nitrobenzohydrazide was efficiently synthesized in two steps by the esterification of 2-nitrobenzoic acid followed by the treatment with hydrazine hydrate in methanol. The structure of 2-nitrobenzohydrazide was established by modern spectro-analytical techniques including FTIR,1H and13C-NMR spectroscopy and unequivocally confirmed by single crystal X-ray diffraction data. 2-Nitrobenzohydrazide crystallized in orthorhombic space group P 21 21 21 with unit cell dimensions a = 4.9764(4) ?, b = 12.5280 (3) ?, c = 12.8512(1) ?, α = β = γ = 90°. A combination of N?H…N and N?H…O hydrogen bonds stabilized the crystal packing of 3. The synthesized compound 3 was assessed as urease inhibitor against Jack bean urease and the results revealed good inhibitory potency with an IC50 value of 4.25 ± 0.08 μM. This inhibition strength was 5-fold higher compared to the reference inhibitor thiourea (IC50 = 21.00 ± 0.11 μM). The molecular docking studies of the synthesized inhibitor 3 inside the active pocket of urease revealed several important binding interactions.
- Abbas, Naeem,Khan, Imtiaz,Batool, Sadaf,Ali, Majid,Farooq, Umar,Khan, Ajmal,Hameed, Shahid,White, Jonathan M.,Ibrar, Aliya
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p. 165 - 170
(2018/06/06)
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- Oxalic acid as the: In situ carbon monoxide generator in palladium-catalyzed hydroxycarbonylation of arylhalides
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An efficient palladium-catalyzed hydroxycarbonylation reaction of arylhalides using oxalic acid as a CO source has been developed. The reaction features high safety, low catalyst loading, and a broad substrate scope, and provides a safe and tractable approach to access a variety of aromatic carboxylic acid compounds. Mechanistic studies revealed the decomposition pattern of oxalic acid.
- Shao, Changdong,Lu, Ailan,Wang, Xiaoling,Zhou, Bo,Guan, Xiaohong,Zhang, Yanghui
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supporting information
p. 5033 - 5040
(2017/07/10)
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- Amberlyst-15 catalysed oxidative esterification of aldehydes using a H2O2 trapped oxidant as a terminal oxidant
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A simple and efficient method has been developed for the selective oxidative esterification of aldehydes using commercially available Amberlyst-15 as a catalyst. H2O2 released from a clathrate structured 4Na2SO4·2H2O2·NaCl oxidant serves as an efficient source of terminal oxidants. Various aromatic, heteroaromatic, and aliphatic aldehydes undergo selective esterification to give good to excellent yield. The heterogeneous catalyst, Amberlyst-15, exhibits high reactivity and can be recycled over several runs. The 4Na2SO4·2H2O2·NaCl oxidant was found to be superior to commonly used oxidizing agents providing an anhydrous, easy to handle and stable form of H2O2
- Gayakwad, Eknath M.,Patil, Vilas V.,Shankarling, Ganapati S.
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p. 2695 - 2701
(2017/04/03)
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- Solvent- and Metal-free Oxidative Esterification of Aromatic Aldehydes Using Urea-2,2-dihydroperoxypropane as a New Solid Oxidant
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Urea-2,2-dihydroperoxypropane as a noble and solid gem-dihydroperoxide derivative was used to transform various aromatic aldehydes to their corresponding benzoate derivatives in the presence of HBr under mild conditions at room temperature in high yields and short reaction times.
- Khosravi, Kaveh,Khalaji, Kobra,Naserifar, Shirin
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p. 303 - 309
(2017/03/27)
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- Polymer supported Zn-salen complexes: An effective one-pot oxidative esterification of aldehydes to carboxylic esters
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Polymer-supported Zn-salen (PS-Zn-salen) complexes were synthesized, characterized and used as a catalyst for one-pot oxidative esterification of aldehydes with alcohols. The PS-Zn-salen heterogeneous catalyst exhibited a high-performance for the oxidative esterification of aldehydes to the corresponding methyl/ethyl esters using hydrogen peroxide as a green oxidant. Due to the synergistic effect of polymer support, the heterogeneous catalyst presented superior catalytic activity and afford 100% conversion of 3,4,5-trimethoxybenzaldehyde and 4-chlorobenzaldehyde to corresponding esters under optimized conditions. The different alcohol substrates study (viz. methyl alcohol, ethyl alcohol, allyl alcohol and benzyl alcohol) showed reasonable selectivity for esters, indicating the scope of the catalysts. Significantly, the synthesized complexes possess good hydrophobic/heterogeneous properties, which permit facile reclamation of the catalyst by using mere filtration. Moreover, the effect of counter anions of complex also studied which indicated that there is no appreciable influence on the conversion of product. The catalyst was reused up to 5th successive run with the average conversion of ester 87.4%. Mechanistic studies have recognized that this “one pot” direct oxidative esterification proceeds through acid formation, proven by a GC–MS. The catalyst is also found to be very stable, up to 280?°C, confirmed by the thermo gravimetric study.
- Balinge, Kamlesh Rudreshwar,Khiratkar, Avinash Ganesh,Bhagat, Pundlik Rambhau
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p. 1085 - 1095
(2017/08/08)
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- Copper-Mediated Decarboxylative Coupling of Benzamides with ortho-Nitrobenzoic Acids by Directed C?H Cleavage
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A copper-mediated decarboxylative coupling of benzamides with ortho-nitrobenzoic acids by 8-aminoquinoline-directed C?H cleavage has been developed. This reaction proceeds smoothly with only a copper salt to produce the corresponding biaryl compounds in good yields. The products can be easily transformed into various nitrogen-containing heterocyclic compounds. Moreover, the combination of copper and a suitable base promotes a decarboxylative C?H arylation and cyclization sequence to deliver phenanthridinone derivatives in one pot.
- Takamatsu, Kazutaka,Hirano, Koji,Miura, Masahiro
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supporting information
p. 5353 - 5357
(2017/04/27)
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- Rhodium-Catalyzed Double Alkyl-Oxygen Bond Cleavage: An Alkyl Transfer Reaction from Bis/Tris(o-alkyloxyphenyl)phosphine to Aryl Acids
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An unprecedented rhodium-catalyzed selective cleavage of double alkyl-oxygen bonds of bis/tris(o-alkyloxyphenyl)phosphine has been realized, in which P atom functions as a directing group and simple aryl acids are the methyl group acceptor to provide methyl esters and a quaternary phosphonium salt. The preliminary mechanism was investigated via an 18O labeling experiment and stoichiometric reaction between a Rh-A crystal and an aromatic acid.
- Zhou, Hui,Zhang, Jinlong,Yang, Huameng,Xia, Chungu,Jiang, Gaoxi
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supporting information
p. 3406 - 3412
(2016/10/21)
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- Copper-Catalyzed O-Methylation of Carboxylic Acids Using DMSO as a Methyl Source
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A copper-catalyzed O-methylation of carboxylic acids using dimethyl sulfoxide (DMSO) as the methyl source is disclosed. This transformation exhibits a broad substrate scope and excellent functional group tolerance. Mechanistic studies indicate that a methyl radical is generated from dimethyl sulfoxide in the reaction process.
- Jia, Jing,Jiang, Qing,Zhao, An,Xu, Bin,Liu, Qiang,Luo, Wei-Ping,Guo, Can-Cheng
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p. 421 - 428
(2016/01/28)
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- Magnetic Co3O4/reduced graphene oxide nanocomposite as a superior heterogeneous catalyst for one-pot oxidative esterification of aldehydes to methyl esters
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A magnetically separable hybrid material consisting of Co3O4 nanoparticles supported on reduced graphene oxide (Co3O4/rGO) was synthesized through a simple co-reduction process of graphene oxide (GO) and cobalt chloride (CoCl2) using sodium borohydride (NaBH4). The Co3O4/rGO heterogeneous catalyst exhibited a high-performance for the oxidative esterification of aldehydes to the corresponding methyl esters using tert-butyl hydroperoxide (TBHP) as an oxidant. Owing to the synergistic effect of rGO support, the hybrid catalyst exhibited superior catalytic activity to the corresponding cobalt oxide catalyst. Importantly, the synthesized hybrid possesses good magnetic properties, which enable facile recovery of the catalyst by using an external magnet.
- Panwar, Vineeta,Al-Nafiey, Amer,Addad, Ahmed,Sieber, Brigitte,Roussel, Pascal,Boukherroub, Rabah,Jain, Suman L.
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p. 88567 - 88573
(2015/11/09)
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- Nitrogen enriched mesoporous organic polymer anchored copper(ii) material: An efficient and reusable catalyst for the synthesis of esters and amides from aromatic systems
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A new copper-grafted mesoporous poly-melamine-formaldehyde (Cu-mPMF) has been synthesized from melamine and paraformaldehyde in DMSO medium, followed by grafting of Cu(ii) at its surface. Cu-mPMF has been characterized by elemental analysis, powder XRD, HR TEM, FE-SEM, N2 adsorption study, FT-IR, UV-vis DRS, TGA-DTA, EPR spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The Cu-grafted mesoporous material showed very good catalytic activity in methyl esterification of benzylic alcohols and amidation of nitriles. Moreover, the catalyst is easily recoverable and can be reused seven times without appreciable loss of catalytic activity in the above reactions. The highly dispersed and strongly bound Cu(ii) sites in the Cu-grafted mesoporous polymer could be responsible for the observed high activities of the Cu-mPMF catalyst. Due to strong binding with the functional groups of the polymer, no evidence of leached copper from the catalyst during the course of reaction emerged, suggesting true heterogeneity in the catalytic process. This journal is
- Molla, Rostam Ali,Iqubal, Md. Asif,Ghosh, Kajari,Kamaluddin,Islam, Sk. Manirul
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p. 6546 - 6559
(2015/04/14)
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- Iron oxalate capped iron-copper nanomaterial for oxidative transformation of aldehydes
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An efficient, sustainable and green procedure for the synthesis of selective orthorhombic iron(oxalate) capped Fe-Cu bimetallic oxide nanomaterial [Fe(ox)Fe-CuOx] was developed using a sodium borohydride reduction of iron(ii) salt in the presence of oxalic acid at room temperature followed by addition of copper sulfate in water. The reported method is a cost-effective chemical route for producing [Fe(ox)Fe-CuOx] nano material at the gram level with a surface area of 78.4 m2 g-1 and a pore volume of 0.141 cm3 g-1. The [Fe(ox)Fe-CuOx] nanomaterials were found to be useful as a recoverable catalyst for the oxidative transformation of an aldehyde to its corresponding ester and acid in presence of hydrogen peroxide.
- Kashyap, Rajarshi,Talukdar, Dhruba Joyti,Pratihar, Sanjay
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p. 1430 - 1437
(2015/02/19)
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- Inclusion complex containing epoxy resin composition for semiconductor encapsulation
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The invention is an epoxy resin composition for sealing a semiconductor, including (A) an epoxy resin and (B) a clathrate complex. The clathrate complex is one of (b1) an aromatic carboxylic acid compound, and (b2) at least one imidazole compound represented by formula (II): wherein R2 represents a hydrogen atom, C1-C10 alkyl group, phenyl group, benzyl group or cyanoethyl group, and R3 to R5 represent a hydrogen atom, nitro group, halogen atom, C1-C20 alkyl group, phenyl group, benzyl group, hydroxymethyl group or C1-C20 acyl group. The composition has improved storage stability, retains flowability when sealing, and achieves an effective curing rate applicable for sealing delicate semiconductors.
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- Ruthenium-catalyzed c-h silylation of 1-arylpyrazole derivatives and fluoride-mediated carboxylation: Use of two nitrogen atoms of the pyrazole Group
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Carboxylation of 1-arylpyrazole derivatives was developed using a ruthenium-catalyzed ortho silylation in conjunction with fluoride-mediated carboxylation with carbon dioxide. The two nitrogen atoms of pyrazole play crucial roles in promoting ortho silylation via the formation of a five-membered ruthenacycle and in accelerating aryl anion formation by lowering the electron density of the aromatic ring. Georg Thieme Verlag Stuttgart New York.
- Mita, Tsuyoshi,Tanaka, Hiroyuki,Michigami, Kenichi,Sato, Yoshihiro
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supporting information
p. 1291 - 1294
(2014/06/10)
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- Copper-catalyzed decarboxylative methylation of aromatic carboxylic acids with PhI(OAc)2
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The copper-catalyzed decarboxylative methylation of aromatic carboxylic acids was developed by using PhI(OAc)2 to provide a new strategy for the methylation of aryl acids through the decarboxylation of alkyl acids. The mechanism and the roles of each reactant in the reaction were investigated extensively. Copyright
- Jiang, Yuyu,Pan, Shulei,Zhang, Yanghui,Yu, Jingxun,Liu, Hongqiang
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supporting information
p. 2027 - 2031
(2014/04/17)
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- Copper-catalyzed methyl esterification of aromatic aldehydes and benzoic alcohols by TBHP as both oxidant and methyl source
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A copper-catalyzed synthesis of methyl esters from aromatic aldehydes in the presence of tert-butyl hydrogen peroxide (TBHP) was developed via a radical reaction mechanism. TBHP acts not only as an efficient oxidant, but also as a green methyl source in such transformation. Moreover, this method could also be efficiently extended to the methyl esterification of benzylic alcohols.
- Li, Pan,Zhao, Jingjing,Lang, Rui,Xia, Chungu,Li, Fuwei
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supporting information
p. 390 - 393
(2014/01/06)
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- Synthesis and evaluation of novel azoles as potent antifungal agents
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Using a rational approach to the design of antifungal agents, a series of azole agents with 1,3,4-oxadiazole side chains were designed and synthesized. The results of preliminary in vitro antifungal tests with eight human pathogenic compounds showed that all of the title compounds exhibited excellent activities against all of the tested fungi except Aspergillus fumigatus. Compounds 11e and 11f were found to be the most effective, with a minimum inhibitory concentration of 0.0039 μg/mL, followed by voriconazole, which has a MIC of 0.0625 μg/mL. The 1,3,4-oxadiazole side chain is not the major contributor but plays a role in eliciting the observed antifungal activity.
- Li, Liangjing,Ding, Hao,Wang, Baogang,Yu, Shichong,Zou, Yan,Chai, Xiaoyun,Wu, Qiuye
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supporting information
p. 192 - 194
(2014/01/17)
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- A one-pot transition-metal-free tandem process to 1,4-benzodiazepine scaffolds
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An efficient and practical method for the synthesis of 1,4-benzodiazepines is reported. This methodology offers a transition-metal-free tandem process in one pot. This process is applicable to the construction of a wide variety of 1,4-benzodiazepines and other tricyclic systems with high potential biological and pharmacological activities. Georg Thieme Verlag Stuttgart · New York.
- Li, Yanqiu,Zhan, Chunjing,Yang, Bingchuan,Cao, Xiaoqun,Ma, Chen
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p. 111 - 117
(2013/03/13)
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- Catalytic methyl transfer from dimethylcarbonate to carboxylic acids
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Although methylation reactions are commonplace, currently used reagents are hazardous, toxic, and/or unstable. Dimethylcarbonate has been put forth as an inexpensive, nontoxic, and green potential methylating reagent. Herein we report a general, base-catalyzed methyl transfer from dimethylcarbonate to carboxylic acids. High selectivity for esterification is observed even in the presence of unprotected phenols, and the mild reaction conditions enable conservation of stereochemistry at epimerizable stereocenters. Isotope-labeling studies suggest a mechanism proceeding by direct methyl transfer from dimethylcarbonate to the substrate.
- Ji, Yuan,Sweeney, Jessica,Zoglio, Jillian,Gorin, David J.
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p. 11606 - 11611
(2013/12/04)
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- Copper-catalyzed methyl esterification reactions via C-C bond cleavage
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The highly effective synthesis of methyl esters from benzylic alcohols, aldehydes, or acids via copper-catalyzed C-C cleavage from tert-butyl hydroperoxide is reported in this paper for the first time. Our protocol is easily accessible and practical, making it a possible supplement for the traditional way.
- Zhu, Yan,Yan, Hong,Lu, Linhua,Liu, Defu,Rong, Guangwei,Mao, Jincheng
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p. 9898 - 9905
(2013/10/22)
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- Direct conversion of N -alkoxyamides to carboxylic esters through tandem nbs-mediated oxidative homocoupling and thermal denitrogenation
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Treatment of N-alkoxyamides with NBS in toluene was found to conveniently afford the corresponding carboxylic esters, including those bearing a bulky or long-chain substituent, in satisfactory to excellent yields. This approach not only represents a convenient and economic approach to a direct transformation of an alkoxyamide moiety into the carboxylic ester functional group, via oxidative homocoupling and the subsequent thermal denitrogenation, but also facilitates the synthesis of sterically hindered carboxylic esters.
- Zhang, Ningning,Yang, Rui,Zhang-Negrerie, Daisy,Du, Yunfei,Zhao, Kang
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p. 8705 - 8711
(2013/09/24)
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- Copper-catalyzed N-methylation of amides and O-methylation of carboxylic acids by using peroxides as the methylating reagents
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The copper-catalyzed N-methylation of amides and O-methylation of carboxylic acids by using peroxides as the methylating reagent are described. Various amides and carboxylic acids were methylated affording N-substituted amides and esters. Tentative mechanistic studies suggest that this reaction is likely to involve a radical process.
- Xia, Qinqin,Liu, Xiaolong,Zhang, Yuejiao,Chen, Chao,Chen, Wanzhi
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supporting information
p. 3326 - 3329
(2013/07/26)
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- Continuous flow oxidation of alcohols and aldehydes utilizing bleach and catalytic tetrabutylammonium bromide
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We report a method for the oxidation of a range of alcohols and aldehydes utilizing a simple flow system of alcohols in EtOAc with a stream of 12.5% NaOCl and catalytic Bu4NBr. Secondary alcohols are oxidized to ketones, aldehydes are oxidized directly to methyl esters in the presence of methanol, and benzylic alcohols are oxidized to either benzaldehydes or methyl esters, depending on the conditions used. The reaction conditions are mild and generally provide complete conversion in 5-30 min.
- Leduc, Andrew B.,Jamison, Timothy F.
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supporting information; experimental part
p. 1082 - 1089
(2012/08/27)
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- Oxidative esterification of benzaldehyde and deactivated aromatic aldehydes with N-bromosuccinimide-pyridine
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(Chemical Equation Presented) Whereas the oxidative esterification of benzaldehyde to methyl benzoate with N-bromosuccinimide (NBS)-pyridine requires dark conditions and 5 equivalents each of NBS and K2CO3 and gave only moderate yield (52%) of the product (McDonald et al. J. Org. Chem. 1989, 54, 1213), simple change of base to pyridine gave the desired product in 83% gas chromatographic yield with only 1 equivalent each of NBS and pyridine. Moreover, the reaction could be conducted without exclusion of light. Aromatic aldehydes bearing electron-withdrawing substituents at meta/para position yielded the corresponding methyl esters in still better yields. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file. Copyright Taylor & Francis Group, LLC.
- Agrawal, Manoj K.,Adimurthy, Subbarayappa,Ghosh, Pushpito K.
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experimental part
p. 2931 - 2936
(2012/07/16)
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- Microwave assisted synthesis of biologically active 4-hydroxy-N′- (phenylcarbonyl)-2H-1,2-benzothiazine-3-carbohydrazide 1,1-dioxide derivatives
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Microwave assisted synthesis of a series of 4-hydroxy-N′- (phenylcarbonyl)-2H-1,2-benzothiazine-3-carbohydrazide 1,1-dioxides from sodium saccharin is reported. Sodium o-benzosulfimide was N-alkylated with ethyl chloroacetate followed by base catalyzed ring expansion to six membered 1,2-benzothiazine through Gabriel-Coleman type rearrangement yielding ethyl 4-hydroxy-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide. It was later condensed with a series of benzohydrazides synthesized from various carboxylic acids to get the title compounds. All the synthesized compounds were subjected to preliminary evaluation for their biological activity against series of Gram positive, Gram negative bacteria and fungi. Some of the compounds showed marked activity against the selected microorganisms.
- Zaheer, Muhammad,Zia-Ur-Rehman, Muhammad,Rahman, Salma,Ahmed, Naveed,Chaudhary, Muhammad Nawaz
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p. 1492 - 1496
(2013/06/27)
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- Total synthesis of farylhydrazones A and B
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Herein we report a concise total synthesis of farylhydrazones A and B, naturally occurring phenylhydrazones recently isolated from cultures of the Cordyceps-colonizing fungus Isaria farinosa, completed in six and five steps respectively starting from 2-nitrobenzoic acid. The synthesis is completely scalable, and highly convergent - making it adaptable for the preparation of analogues and investigation into the biological activity of these unique natural products.
- Tsang, Tsz-Ho,Gubler, Daniel A.
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supporting information; experimental part
p. 4243 - 4244
(2012/09/07)
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- Synthesis, molecular modeling and biological evaluation of 2-(benzylthio)-5-aryloxadiazole derivatives as anti-tumor agents
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A series of 2-(benzylthio)-5-aryloxadiazole derivatives have been designed and synthesized, and their biological activities are also evaluated for EGFR inhibitory activity. Fourteen compounds among the twenty compounds are reported for the first time. Their chemical structures are characterized by 1H NMR, MS, and elemental analysis. Anti-proliferative and EGFR inhibition assay results have demonstrated that compound 3e shows the most potent biological activity (IC50 = 1.09 μM for MCF-7 and IC50 = 1.51 μM for EGFR). Docking simulation has been performed to position compound 3e into the EGFR active site to determine the probable binding model, with an estimated binding free energy value of -10.7 kcal/mol. Compound 3e with potent inhibitory activity in tumor growth inhibition may be a promising anti-tumor leading compound for the further research.
- Liu, Kai,Lu, Xiang,Zhang, Hong-Jia,Sun, Juan,Zhu, Hai-Liang
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scheme or table
p. 473 - 478
(2012/03/13)
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- Synthesis and antihyperlipidemic activity of some novel 4-(substitutedamino)-5-substituted-3-mercapto-(4H)-1,2,4-triazoles
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Hyperlipidemia is considered one of the key factors for cardiovascular diseases. Based on earlier work on a series of 5-alkyl-4-aryl-3-mercapto-(4H)-1, 2,4-triazoles, for further lead modification, a series of 4-(substituted)amino- 5-substituted-3-mercapto-(4H)-1,2,4-triazoles was designed. Target compounds were synthesized by the well known Hoggarth synthesis of substituted 1,2,4-triazoles. Synthesized compounds were screened for lipid lowering activity using the "Poloxamer 407 induced hyperlipidemia in rats" model at a dose of 100 mg/kg p. o. Compounds were found to alter serum lipid levels significantly. Most of the compounds significantly reduced serum cholesterol and triglyceride levels. Some of the compounds were found to reduce triglycerides and elevate high density lipoprotein (HDL) levels more than the standard drug atorvastatin (CAS 134523-03-8). Compounds with chloro substitution on aryl rings were found more active in reducing serum lipid levels than other substitutions. ECV ? Editio Cantor Verlag.
- Chhabria, Mahesh T.,Suhagia, Bhanubhai N.,Brahmkshatriya, Pathik S.,Raval, Priyesha M.
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scheme or table
p. 452 - 457
(2012/06/16)
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- Single-step conversion of electron-deficient aldehydes into the corresponding esters in aqueous alcohols in the presence of iodine and sodium nitrite
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The direct conversion of aldehydes into their corresponding esters in the presence of iodine and sodium nitrite in aqueous alcohols is reported. In all these reactions, alcohol serves as reactant and also as reaction medium. Almost quantitative yields were obtained with aldehydes containing electron-withdrawing substituents and heterocyclic aldehydes. Georg Thieme Verlag Stuttgart.
- Kiran,Ikeda, Reiko,Sakai, Norio,Konakahara, Takeo
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experimental part
p. 276 - 282
(2010/03/26)
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- Oxidative esterification of aldehydes with alcohols and phenols in air
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Nucleophilic carbene-catalysed oxidative esterification of aldehydes with alcohols and phenols without additional oxidant under an air atmosphere has been achieved, which provides a metal-free new methodology for the oxidative esterification of aldehydes.
- Cheng, Shuanghua,Chen, Jiuxi,Gao, Wenxia,Jin, Huile,Ding, Jinchang,Wu, Huayue
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experimental part
p. 130 - 132
(2010/06/19)
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- Regioselective nitration of deactivated mono-substituted benzenes using acyl nitrates over reusable acidic zeolite catalysts
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Nitration of benzonitrile was investigated using a nitric acid/acid anhydride/zeolite catalyst system under different reaction conditions. Trifluoroacetic and chloroacetic anhydrides were found to be the most active among the anhydrides tried. Also, zeolites Hβ and Fe3+β (Si/ Al = 12.5) were found to be the most active catalysts. For example, nitration of benzonitrile with trifluoroacetyl nitrate under reflux conditions in dichloromethane gave 3- and 4-nitrobenzonitriles in quantitative yield, of which the para-isomer represented 24-28%. The yield of para-isomer was improved to 33% when passivated Hβ was used under similar reaction conditions. This is easily the most para-selective nitration of benzonitrile ever recorded. Also, no ortho-isomer was formed under the conditions tried. The zeolite can be easily recovered, regenerated by heating and reused up to six times to give results similar to those obtained with a fresh sample of the catalyst. The nitration system was applied successfully to a range of deactivated mono-substituted benzenes to give para-isomers in significantly higher proportions than in the corresponding traditional nitration reactions.
- Smith, Keith,Ajarim, Mansour D.,El-Hiti, Gamal A.
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experimental part
p. 270 - 278
(2010/12/19)
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- Catalytic oxidative esterification of aldehydes and alcohols using KI-TBHP
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A simple and mild procedure for the facile oxidative esterification of aldehydes and alcohols using potassium iodide (KI) in combinzation with tert-butyl hydroperoxide (TBHP) as an external oxidant is described. Oxidative esterification is induced by iodine generated in situ by the chemical oxidation of KI with TBHP.
- Reddy, K. Rajender,Venkateshwar,Maheswari, C. Uma,Prashanthi
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experimental part
p. 186 - 195
(2010/03/24)
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- Iron-catalyzed one-pot oxidative esterification of aldehydes
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A highly efficient, mild, and simple protocol for Fe(ClO4) 3·xH2O-catalyzed oxidative esterification of aldehydes was developed. Several aromatic and aliphatic aldehydes reacted with simple primary and secondary alcohols, used as the solvent, smoothly in the presence of an iron salt catalyst (10 mol-%) and hydroperoxide (4 equiv.) as an oxidant to generate the corresponding esters in good to excellent yields. Wiley-VCH Verlag GmbH & Co. KGaA, 2009.
- Wu, Xiao-Feng,Darcel, Christophe
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supporting information; experimental part
p. 1144 - 1147
(2009/07/11)
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- A synthesis of sulfonamide analogs of platensimycin employing a palladium-mediated carbonylation strategy
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The monodentate ligand 1,3,5,7-tetramethyl-2,4,8-trioxa-6-phenyl-6-phospha-adamantane (PA-Ph) is shown to be highly effective in palladium-catalyzed carbonylative cross-coupling. Aryl and vinyl halides were efficiently converted to carboxylic acids, amides and to primary, secondary, and tertiary esters, respectively. Application of the Pd(OAc)2/PA-Ph (1:1) catalyst system proved critical in the methoxycarbonylation of a functionalized nitroresorcinol halide, allowing convenient access to novel platensimycin sulfonamide analogs.
- McNulty, James,Nair, Jerald J.,Capretta, Alfredo
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scheme or table
p. 4087 - 4091
(2009/12/01)
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- NaIO4/LiBr-mediated direct conversion of benzylic alcohols and aromatic aldehydes to aromatic esters
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Aromatic aldehydes or benzylic alcohols are directly converted to the corresponding aromatic esters in high yields on treatment with methanol or ethanol mediated by sodium metaperiodate (NaIO4)/LiBr in an acidic medium. Copyright Taylor & Francis Group, LLC.
- Shaikh, Tanveer Mohammad Ali,Emmanuvel, Lourdusamy,Sudalai, Arumugam
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p. 2641 - 2646
(2008/02/12)
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- Alpha- haloenamine reagents
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The present invention describes immobilized haloenamine reagents, immobilized tertiary amides, methods for their preparation, and methods of use.
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- Relative reactivity of methyl iodide to ethyl iodide in nucleophilic substitution reactions in acetonitrile and partial desolvation accompanying activation
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Through the examination of empirical correlations involving activation parameters for nucleophilic substitution of methyl iodide and of ethyl iodide, nucleophiles have been classified into three series: (1) nucleophiles with two equivalent reaction sites, (2) nucleophiles with a chlorine atom in the para-position, and (3) nucleophiles with a single reaction site. Three types of partial desolvation processes accompanying activation have been deduced on the basis of these classifications. A major factor determining the relative reactivity of methyl iodide to ethyl iodide in the substitution reaction of an anionic nucleophile having a single reaction site in acetonitrile (kMeI/kEtI) is suggested to be partial desolvation around the nucleophilic center on going from reactant to transition-state.
- Kondo, Yasuhiko,Urade, Miyuki,Yamanishi, Yukari,Chen, Xinyu
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p. 1449 - 1454
(2007/10/03)
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- An improved method for the esterification of aromatic acids with ethanol and methanol
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A mixed catalyst Fe2(SO4)3·xH2O/ concentrated H2SO4 has been used to catalyze the esterification of aromatic acids with ethanol and methanol. This catalyst system is found to be effective for the rapid reactions and the esterification yields are excellent.
- Xu,Liu,Chen,Ma
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p. 2113 - 2117
(2007/10/03)
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