- Acylanthranils. 10. Influence of Hydrogen Bonding on Hydrolysis of Acetylanthranil in Organic Solvents
-
The hydrolysis of acetylanthranil (1) to give o-acetamidobenzoic acid (2) in organic solvents at room temperature was monitored by proton NMR and/or gravimetrically.The results show that the second-order rate constant in benzene is about equal to that in water at pH 6.8.The corresponding rate constant for hydrolysis by a stoichiometric amount of water in proton-acceptor solvents decreases in the order benzene > dimethyl-d6 sulfoxide > acetone-d6 > dimethylformamide-d7 > pyridine, and for hydrolysis in proton donor solvents, it decreases in the order benzene > chloroform-d > acetonitrile-d3.The observed second-order rate "constant" in organic solvents, however, is not a true constant, since it increases linearly with water concentration.It was observed also that the plots of log / as a function of time, t, show an inflection at some time, ti, that appears to correspond to a critical equilibrium concentration of available proton from the acid product 2.The magnitude of ti is decreased considerably by addition of 2 at time zero, and it is eliminated completely by addition of HCl.On the other hand, it is increased considerably by addition of solutes that are strong proton acceptors, such as 1,8-bis(dimethylamino)naphthalene or 1,4-diazabicyclooctane.These results are consistent with the hypothesis that hydrolysis of 1 in organic solvents involves interaction with molecular clusters of water such as (H2O)n in benzene, S*HOH*S or (HOH*S)n in proton-acceptor solvents, S, and H2O*HS in proton donor solvents, SH.
- Errede, L. A.,McBrady, J. J.,Tiers, G. V. D.
-
-
Read Online
- N-Acetylanthranilic Acid (o-Acetamidobenzoic Acid), a Strongly Triboluminescent Material
-
C9H9NO3, orthorombic, Fdd2, a = 10.845 (9), b = 30.204 (7), c = 10.575 (4) Angstroem, V = 3464 Angstroem3, Dx = 1.378, Dm = 1.36 Mg m-3 (by flotation), Z = 16.The final R = 0.064 for 799 reflexions and 118 variables.The molecules are interbonded by hydrogen bonds throught the O(1) of the carboxyl group and O(31) of the acetamide group forming chains on alternating planes approximately parallel to (301) and .
- Mascarenhas, Y. P.,Almeida, V. N. de,Lechat, J. R.,Barelli, N.
-
-
Read Online
- Synthesis and X-ray structure analysis of 2-acetylamino-benzoic acid
-
The title compound crystallizes in the orthorhombic space group Fdd2 with unit cell parameters a = 10.848(1) , b = 30.264(1) and c = 10.577(1) , V = 3472.47(2) 3, and Z = 4. The final reliability index is 0.030 for 700 observed reflections. Nitrogen of the amide group and carbon atom of the acid group deviate significantly below and above the plane of the phenyl ring. The crystal cohesion is accentuated by NbondHO and ObondHO hydrogen bonds.
- Rajnikant,Dinesh,Kamni,Deshmukh
-
-
Read Online
- Oxidative Cleavage of Indoles Mediated by Urea Hydrogen Peroxide or H2O2 in Polar Solvents
-
The oxidative cleavage of indoles (Witkop oxidation) involving the use of H2O2 or urea hydrogen peroxide in combination with a polar solvent has been described. Among these solvents, 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) stands out as the one affording the corresponding 2-ketoacetanilides generally in higher yields The protocol described has also enabled the oxidation of different pyrroles and furans derivatives. Furthermore, the procedure was implemented in a larger-scale and HFIP was distilled from the reaction mixture and reused (up to 4 cycles) without a significant detriment in the reaction outcome, which remarks its sustainability and applicability. (Figure presented.).
- Llopis, Natalia,Gisbert, Patricia,Baeza, Alejandro
-
supporting information
p. 3245 - 3249
(2021/06/08)
-
- Cleavage of Carboxylic Esters by Aluminum and Iodine
-
A one-pot procedure for deprotecting carboxylic esters under nonhydrolytic conditions is described. Typical alkyl carboxylates are readily deblocked to the carboxylic acids by the action of aluminum powder and iodine in anhydrous acetonitrile. Cleavage of lactones affords the corresponding ω-iodoalkylcarboxylic acids. Aryl acetylates undergo deacetylation with the participation of the neighboring group. This method enables the selective cleavage of alkyl carboxylic esters in the presence of aryl esters.
- Sang, Dayong,Yue, Huaxin,Fu, Yang,Tian, Juan
-
p. 4254 - 4261
(2021/03/09)
-
- MODIFIED PROTEINS AND PROTEIN DEGRADERS
-
Provided herein are compounds, pharmaceutical compositions, and methods for binding or degrading target proteins. Further provided herein are compounds having a DNA damage-binding protein 1 (DDB1) binding moiety. Some such embodiments include a linker. Some such embodiments include a target protein binding moiety. Further provided herein are ligand-DDB1 complexes. Further provided herein are in vivo modified DDB1 proteins.
- -
-
Paragraph 00240; 00243; 00244
(2021/12/08)
-
- Design and synthesis of novel tranilast analogs: Docking, antiproliferative evaluation and in-silico screening of TGFβR1 inhibitors
-
The discovery of the antiproliferative potential of tranilast prompted additional studies directed at understanding the mechanisms of tranilast action. Its inhibitory effect on cell proliferation depends principally on the capacity of tranilast to interfere with transforming growth factor beta (TGFβR1) signaling. This work summarizes design, synthesis and biological evaluation of sixteen novel tranilast analogs on different tumors such as PC-3, HepG-2 and MCF-7 cell lines. The in vitro cytotoxicity was evaluated using MTT assay showed that, twelve compounds out of sixteen showed higher cytotoxic activities (IC50’s 1.1–6.29 μM), than that of the reference standard, 5-FU (IC50 7.53 μM). The promising cytotoxic hits (4b, 7a, b and 14c-e), proved to be selective to cancer cells when their cytotoxicity's are examined on human normal cell line (WI-38). Then they are investigated for their possible mode of action as TGFβR1 inhibitors; remarkable inhibition of TGFβR1 by these hits was observed at the range of IC50 0.087–3.276 μM. The cell cycle analysis of the most potent TGFβR1 inhibitor, 4b revealed cell cycle arrest at G2/M phase on prostate cancer cells. Additionally, it is clearly indicated apoptosis induction at Pre-G1 phase, this is substantiated by significant increase in the expression on the tumor suppressor gene, p53 and up regulation the level of apoptosis mediator, caspase-3. In addition, in silico study was performed for validating the physicochemical and ADME properties which revealed that, all compounds are orally bioavailable with no side effects complying with Lipinski rule. The proposed mode of action can be further explored on the light of molecular modeling simulation of the most potent compounds, 4b and 14e which were docked into the active sites of TGFβR1 to predict their affinities toward the receptor.
- Ismail, Magda M.F.,El-Zahabi, Heba S.A.,Ibrahim, Rabab S.,Mehany, Ahmed B.M.
-
-
- Preparation method of dye intermediate applicable to digital jet printing or dyeing
-
The invention relates to a preparation method of a dye intermediate applicable to digital jet printing or dyeing. The active dye intermediate is 2-carboxyl-4-beta sulfonylsulfone ethyl sulfate-aniline. The method comprises the following steps of (1) acetylation; (2) sulfochlorination; (3) reduction; (4) hydroxyethylation; (5) esterification hydrolysis. The dye intermediate prepared by the method is applicable to synthesis of digital jet printing or dyeing.
- -
-
Paragraph 0030
(2019/02/06)
-
- A straightforward TBHP-mediated synthesis of 2-amidobenzoic acids from 2-arylindoles and their antimicrobial activity
-
A simple and highly efficient strategy has been developed for the synthesis of 2-amidobenzoic acids through the tert-butyl hydroperoxide (TBHP)-mediated oxygenation and sequential ring opening of 2-arylindoles in a one-pot fashion under metal-free aerobic conditions. The developed synthetic protocol is operationally simple, tolerates a wide range of functional groups, and is amenable to the gram-scale. Radical trapping experiments revealed that the reaction involves a radical pathway. The synthesized compounds (2a-s) were tested for in vitro antimicrobial activity. Among all screened compounds, 2d showed the maximum antibacterial activity against P. aerugunosa (ZOI = 17 mm, MIC = 32 μg mL-1) and compounds 2d and 2p showed the maximum (32 μg mL-1) antifungal activity against A. flavus and C. albicans.
- Patel, Om P.S.,Dhiman, Shiv,Khan, Shahid,Shinde, Vikki N.,Jaspal, Sonam,Srivathsa, Manu R.,Jha, Prabhat N.,Kumar, Anil
-
p. 5962 - 5970
(2019/06/24)
-
- A photochemical approach for evaluating the reactivity of substituted lappaconitines
-
Lappaconitine (LC) is a natural diterpenoid alkaloid (DTA), acting as a human heart sodium channel blocker and possessing a wide range of biological activities, the cellular and molecular mechanisms of which are widely studied. This interest is due to the fact that various representatives of this DTA class show opposite biological activities. The possible reasons for this difference seem to be related to the peculiarities of the substituent effect on the drug-receptor binding process. In this work, the influence of substituents on the reactivity of LC and its derivatives has been studied by using elementary processes of photodecomposition. The given approach includes the joint analysis of the photophysical properties of the studied systems and their photodecomposition quantum yields. It allows us to trace the influence of substituents, located in the diterpenoid skeleton and anthranilic fragment, on processes in both moieties of LC. Summarizing the data obtained, an inverse dependence of fluorescence and photodegradation quantum yields has been observed. This correlation established for LCs, in particular, allows one to propose a way to evaluate the photostability of potential drugs based on fluorescence analysis. This would be appropriate for compounds in which the reactivity depends on intersystem crossing, i.e. in the cases where the initial and reacting excited states differ in multiplicity.
- Ageeva, Aleksandra A.,Khramtsova, Ekaterina A.,Plyusnin, Viktor F.,Stepanov, Aleksandr A.,Leshina, Tatyana V.
-
p. 192 - 199
(2018/02/22)
-
- Synthesis, molecular modeling of N-acyl benzoazetinones and their docking simulation on fungal modeled target
-
A series of stable N-acyl benzoazetinones have been synthesized in moderate to good yields (58–85%) from easily available substrates such as 2-(N-acyl) amino benzoic acids through intramolecular amidation under mild conditions. These geometry-optimized benzoazetinones were docked in the model target of P450, class CYP53A15, a benzoate 4-monooxygenase abundantly found in the genome of ascomycetes and Basidiomycetes classes of pathogenic fungi. Low per residue root-mean-square deviation (RMSD) of modeled structure of the enzyme indicated similar topology as template (4D6Z.pdb). Observed score judges site-specific docking, and the interaction of quantum mechanically optimized benzoazetinone derivatives with the target enzyme. These results suggest that 3i is the best antifungal agent. The specific hydrophobic substituent in the benzoazetinones contributed to the stability of ligand–target complex. Overall, the study provided insight into the specificity of the site-specific interactions, thereby, facilitating the possibility of development of broad-spectrum antifungal agents against opportunistic and infectious fungi.
- Ansary, Inul,Das, Arijit,Sen Gupta, Parth Sarthi,Bandyopadhyay, Amal Kumar
-
supporting information
p. 1375 - 1386
(2017/07/25)
-
- TBHP/CoCl2-mediated intramolecular oxidative cyclization of N-(2-formylphenyl)amides: An approach to the construction of 4H-3,1-benzoxazin-4-ones
-
The intramolecular oxidative cyclization of N-(2-formylphenyl)amides has been realized through an oxidative C(sp2)-O(sp2) bond-forming reaction between an aldehyde carbon and amide oxygen. This new strategy, which uses tert-butyl hydroperoxide (TBHP) as an oxidant and CoCl2 as the catalyst, allows for the efficient Co-catalyzed synthesis of useful benzoxazin-4-one derivatives and features readily available starting materials and mild reaction conditions. The intramolecular cyclization of N-(2-formylphenyl)amides has been realized through an oxidative C(sp2)-O(sp2) bond-forming reaction between an aldehyde carbon and amide oxygen. This new strategy, which uses tert-butyl hydroperoxide (TBHP) as the oxidant and CoCl2 as the catalyst, allows for the efficient Co-catalyzed synthesis of useful benzoxazin-4-one derivatives.
- Yu, Junchao,Zhang-Negrerie, Daisy,Du, Yunfei
-
p. 562 - 568
(2016/02/18)
-
- Tunable microwave-assisted method for the solvent-free and catalyst-free peracetylation of natural products
-
Background: The peracetylation is a simple chemical modification that can be used to enhance the bioavailability of hydrophilic products and to obtain safe and stable pro-drugs. Results: A totally green, solvent-free and catalyst-free microwave (MW)-assisted method for peracetylation of natural products such as oleuropein, alpha-hederin, quercetin and rutin is presented. By simply tuning the MW heating program, polyols with chemical diverse -OH groups or thermolabile functionalities can be peracetylated to improve the biological activity without degradation of the natural starting molecules. An evaluation of the process greenness was performed. Conclusion: The method is potentially universally applicable for green acetylation of hydrophilic biological molecules, potentially easily scalable for industrial applications, including pharmaceutical, cosmetic and food industry.
- Oliverio, Manuela,Costanzo, Paola,Nardi, Monica,Calandruccio, Carla,Salerno, Raffaele,Procopio, Antonio
-
supporting information
p. 2222 - 2233
(2016/11/17)
-
- The amide C-N bond of isatins as the directing group and the internal oxidant in Ru-catalyzed C-H activation and annulation reactions: Access to 8-amido isocoumarins
-
The N-O, N-N and O-O bonds are the frequently used internally oxidative directing groups used in various redox-neutral coupling reactions. The sole use of the C-N bond as the oxidizing directing group was reported recently by Li X. and co-workers for the Rh(iii)-catalyzed C-H activation of phenacyl ammonium salts. Herein, we report the use of the amide C-N bond of isatins as the oxidizing directing group for the Ru(ii)-catalyzed redox-neutral C-H activation and annulation reactions with alkynes which afford 8-amido isocoumarins. The reaction also features excellent regioselectivity with alkyl aryl substituted alkynes.
- Kaishap, Partha Pratim,Sarma, Bipul,Gogoi, Sanjib
-
supporting information
p. 9809 - 9812
(2016/08/04)
-
- Palladium-catalyzed C-H bond carboxylation of acetanilides: An efficient usage of N,N-dimethyloxamic acid as the carboxylate source
-
N,N-Dimethyloxamic acid can be successfully employed as a carboxylate precursor in the palladium-catalyzed direct C-H carboxylation of acetanilides. The reaction proceeds smoothly under mild conditions over a broad range of substrates with high functional group tolerance, affording substituted N-acyl anthranilic acids in moderate to high yields.
- Wu, Yinuo,Jiang, Cheng,Wu, Deyan,Gu, Qiong,Luo, Zhang-Yi,Luo, Hai-Bin
-
supporting information
p. 1286 - 1289
(2016/01/15)
-
- Synthesis and evaluation of quinazolines as inhibitors of the bacterial cell division protein FtsZ
-
The bacterial cell division protein FtsZ is one of many potential targets for the development of novel antibiotics. Recently, zantrin Z3 was shown to be a cross-species inhibitor of FtsZ; however, its specific interactions with the protein are still unknown. Herein we report the synthesis of analogues that contain a more tractable core structure and an analogue with single-digit micromolar inhibition of FtsZs GTPase activity, which represents the most potent inhibitor of Escherichia coli FtsZ reported to date. In addition, the zantrin Z3 core has been converted to two potential photo-cross-linking reagents for proteomic studies that could shed light on the molecular interactions between FtsZ and molecules related to zantrin Z3.
- Nepomuceno, Gabriella M.,Chan, Katie M.,Huynh, Valerie,Martin, Kevin S.,Moore, Jared T.,Obrien, Terrence E.,Pollo, Luiz A. E.,Sarabia, Francisco J.,Tadeus, Clarissa,Yao, Zi,Anderson, David E.,Ames, James B.,Shaw, Jared T.
-
supporting information
p. 308 - 312
(2015/03/30)
-
- Identification of degradation products of indigoids by tandem mass spectrometry
-
The study concerns identification of photodegradation products of indigotin, indirubin and isoindigo. Experimental methodology consists of degradation of standard solutions of indigoids in a solar box and analysis of samples taken at different aging time by using capillary high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometric and spectrophotometric detectors. Identification of the formed compounds was based on careful interpretation of the electrospray ionization MS/MS spectra. Apart from the well-known degradation products of indigoids: isatin, isatoic anhydride and anthranilic acid, another seven species were also identified, and their proposed structures were confirmed by high-resolution molecular masses measurements; according to the best knowledge of authors, they have not been reported so far. The obtained results formed the basis for postulating mechanism of the process. Moreover, the MRM (Multiple Reaction Monitoring) method was developed for the identification of natural dyes and their degradation products in textiles of historical value. Apart from such colorants as indigotin and flavonoids, also presence of degradation products of indigoids was confirmed.
- Witkos?, Katarzyna,Lech, Katarzyna,Jarosz, MacIej
-
p. 1245 - 1251
(2015/11/09)
-
- The effect of hydrogen bond on Br?nsted acid-catalyzed intramolecular hydroamination of unfunctionalized olefins
-
The catalytic activity of benzoic acid could be increased by introducing a hydrogen bond donor group at the ortho-position. Preliminary DFT calculation indicated that the activation of CC double bond was realized by the action of both the carboxyl group and the hydrogen bond donor. The amino group was brought to the activated CC bond by the interaction between the carboxyl oxygen and amino proton. This interaction also increased the nucleophilicity of the amino group. Thus, in the presence of 20 mol % of 2-(trifluoromethanesulfonamido)benzoic acid, intramolecular hydroamination of unfunctionalized olefins gave the corresponding products in up to 95% isolated yields.
- Li, Ting-Ting,Liu, Gong-Qing,Wang, Yu-Mei,Cui, Bin,Sun, Hui,Li, Yue-Ming
-
supporting information
p. 7003 - 7009
(2015/08/19)
-
- Catalytic Mechanism of Cofactor-Free Dioxygenases and How They Circumvent Spin-Forbidden Oxygenation of Their Substrates
-
Dioxygenases catalyze a diverse range of biological reactions by incorporating molecular oxygen into organic substrates. Typically, they use transition metals or organic cofactors for catalysis. Bacterial 1-H-3-hydroxy-4-oxoquinaldine-2,4-dioxygenase (HOD) catalyzes the spin-forbidden transfer of dioxygen to its N-heteroaromatic substrate in the absence of any cofactor. We combined kinetics, spectroscopic and computational approaches to establish a novel reaction mechanism. The present work gives insight into the rate limiting steps in the reaction mechanism, the effect of first-coordination sphere amino acids as well as electron-donating/electron-withdrawing substituents on the substrate. We highlight the role of active site residues Ser101/Trp160/His251 and their involvement in the reaction mechanism. The work shows, for the first time, that the reaction is initiated by triplet dioxygen and its binding to deprotonated substrate and only thereafter a spin state crossing to the singlet spin state occurs. As revealed by steady- and transient-state kinetics the oxygen-dependent steps are rate-limiting, whereas Trp160 and His251 are essential residues for catalysis and contribute to substrate positioning and activation, respectively. Computational modeling further confirms the experimental observations and rationalizes the electron transfer pathways, and the effect of substrate and substrate binding pocket residues. Finally, we make a direct comparison with iron-based dioxygenases and explain the mechanistic and electronic differences with cofactor-free dioxygenases. Our multidisciplinary study confirms that the oxygenation reaction can take place in absence of any cofactor by a unique mechanism in which the specially designed fit-for-purpose active-site architecture modulates substrate reactivity toward oxygen.
- Hernández-Ortega, Aitor,Quesne, Matthew G.,Bui, Soi,Heyes, Derren J.,Steiner, Roberto A.,Scrutton, Nigel S.,De Visser, Sam P.
-
supporting information
p. 7474 - 7487
(2015/06/30)
-
- Substrate-assisted O2 activation in a cofactor-independent dioxygenase
-
In contrast to the majority of O2-activating enzymes, which depend on an organic cofactor or a metal ion for catalysis, a particular group of structurally unrelated oxygenases is functional without any cofactor. In this study, we characterized the mechanism of O2 activation in the reaction pathway of a cofactor-independent dioxygenase with an α/β-hydrolase fold, which catalyzes the oxygenolytic cleavage of 2-alkyl-3-hydroxy-4(1H)-quinolones. Chemical analysis and electron paramagnetic resonance spectroscopic data revealed that O2 activation in the enzyme's active site is substrate-assisted, relying on single electron transfer from the bound substrate anion to O2 to form a radical pair, which recombines to a C2-peroxide intermediate. Thus, an oxygenase can function without a cofactor, if the organic substrate itself, after activation to a (carb)anion by an active-site base, is intrinsically reactive toward molecular oxygen.
- Thierbach, Sven,Bui, Nguyen,Zapp, Josef,Chhabra, Siri Ram,Kappl, Reinhard,Fetzner, Susanne
-
p. 217 - 225
(2014/03/21)
-
- Design and synthesis of quinazolinone tagged acridones as cytotoxic agents and their effects on EGFR tyrosine kinase
-
In a quest for finding potent cytotoxic molecules, we have designed and synthesized a new scaffold by tagging quinazolinones with an acridone moiety. The new acridone-4-carboximide derivatives were evaluated for their cytotoxic potentials against the MCF7 breast cancer cell line and three colon cancer cell lines (LS174T, SW1398, and WiDr). Compound 26 showed relatively potent cytotoxic activity among the derivatives, against all the cell lines tested. Mechanistic studies for the selected derivatives 7, 8, 16, 17, 25, and 26 were conducted through in vitro EGFR tyrosine kinase inhibition studies. The results indicate that compound 26 has a better EGFR tyrosine kinase inhibitory profile. The in vitro EGFR inhibition data was correlated with the cytotoxic properties, and molecular docking studies were performed with regard to the receptor autophosphorylation sites of the protein kinase domain of the EGFR.
- Babu, Yarlagadda Rajesh,Bhagavanraju, Mantripragada,Reddy, Gade Deepak,Peters, Godefridus J.,Prasad, Velivela V. S. Rajendra
-
p. 624 - 634
(2014/11/08)
-
- Formation of tryptanthrin compounds upon Oxone-induced dimerization of indole-3-carbaldehydes
-
Tryptanthrin is a natural product with numerous important pharmacological properties. Tryptanthrin and its analogs are commonly prepared by condensation of isatoic anhydride and isatin. In this Letter we investigate the formation of tryptanthrin derivatives upon Oxone-induced oxidative dimerization of indole-3-carbaldehydes.
- Nelson, Amber C.,Kalinowski, Emily S.,Jacobson, Taylor L.,Grundt, Peter
-
p. 6804 - 6806
(2013/11/19)
-
- Dimethyldioxirane oxidation of n-substituted-2-methylindoles to indoxyls and bisindoxyls
-
Oxidation of 2-methylindoles 12a-f with dimethyldioxirane (DMD) revealed that N-unprotected 12b,f and protected N-carbamate 2-methylindole 12c afforded indoxyls 16b,c and o-(N-propionyl)aminobenzoic acid 17f as the main products, while N-alkyl- or N-aryl-2-methylindoles 12a,d,e gave 1,5′-diphenyl- 4′,5′-dihydro-3′H-spiro[indole-2,2′-pyrano[3,2-b]indol] -3(1H)-one (10), 2,3′-bisindolin-3-ones 13, dispiro[indole-2,2′- furan-5′,2″-indole]diones 14 or 2-[(3-oxoindolin-2-yl)methyl]-2- hydroxyindolin-3-ones 15. The structure of dimers 10, 13a,d,e, 14a,d and 15a,d followed from NMR measurements, X-ray diffraction analysis confirmed those structures of 13a,d,e, 14a,d and 15d, and some mechanistic implications are discussed.
- Aristeo-Dominguez, Alberto,Melendez-Rodriguez, Myriam,Castillo, Oscar R. Suarez,Contreras-Martinez, Yaneth M. A.,Suarez-Ramirez, Lizbeth,Trejo-Carbajal, Nayely,Morales-Rios, Martha S.,Joseph-Nathan, Pedro
-
p. 1249 - 1267
(2013/07/19)
-
- Design, synthesis and anticonvulsant evaluation of N-(benzo[d]thiazol-2- ylcarbamoyl)-2-methyl-4-oxoquinazoline-3(4H)-carbothioamide derivatives: A hybrid pharmacophore approach
-
Novel N-(benzo[d]thiazol-2-ylcarbamoyl)-2-methyl-4-oxoquinazoline-3(4H)- carbothioamide derivatives were synthesized and evaluation of their anticonvulsant effects was done using various models of experimental epilepsy. Initial anticonvulsant activities of the compounds were investigated using intraperitoneal (i.p.) maximal electroshock shock (MES), subcutaneous pentylenetetrazole (scPTZ) seizure models in mice. The quantitative assessment after oral administration in rats showed that the most active was 2-methyl-4-oxo-N-(6-(trifluoromethoxy)benzo[d]thiazol-2-ylcarbamoyl) quinazoline-3(4H)-carbothioamide (SA 24) with ED50 values of 82.5 μmol/kg (MES) and 510.5 μmol/kg (scPTZ). This molecule was more potent than phenytoin and ethosuximide which were used as reference antiepileptic drugs. To explain the possible mechanism for anticonvulsant action, some of the selected active compounds were subjected to GABA (γ-amino butyric acid) assay and AMPA ((S)-2-amino-3-(3-hydroxyl-5-methyl-4-isoxazolyl) propionic acid) induced seizure test.
- Malik, Sachin,Bahare, Radhe Shyam,Khan, Suroor Ahmad
-
-
- Substituent effects on energetics of peptide-carboxylate hydrogen bonds as studied by 1H NMR spectroscopy: Implications for enzyme catalysis
-
Substituent effects in N-H···O hydrogen bonds were estimated by comparing the acidities of two series of model compounds: N-benzoylanthranilic acids (A) and 4-benzoylamidobenzoic acids (B). Intramolecular N-H···O hydrogen bonds were found to be present in the A series of compounds, while B acids were used as control models. The respective pKa values for A and B acids were determined experimentally in DMSO solution using proton NMR spectroscopy. With X = H, the pKa for A and B acids were observed to be 7.6 and 11.6, respectively, a difference of 4.0 units (ΔpKa). However, with X = p-NO 2, the ΔpKa value between A and B acids increased to 4.7 units: the pKa values for A and B acids were determined as 6.7 and 11.4, respectively. The ΔpKa values between A and B acids as a function of the X substituents were studied in 10 other examples. The effects of X substituents in A acids could be predicted on the basis of the observed linear Hammett correlations, and the sensitivity of each substituent effect was found to be comparable to those observed for the ionization of substituted benzoic acids (ρ = 1.04 for A acids, and ρ = 1.00 for benzoic acids).
- Emenike, Bright U.,Liu, Albert Tianxiang,Naveo, Elsy P.,Roberts, John D.
-
p. 11765 - 11771
(2014/01/06)
-
- Kinetics and mechanism of the oxidation of substituted benzaldehydes with bis(pyridine)silver permanganate
-
The oxidation of thirty-six ortho-, meta- and para-substituted benzaldehydes by bis(pyridine)silver permanganate (BPSP) resulted in the formation of the corresponding benzoic acids. The reaction is first order with respect to both BPSP and aldehydes. The reaction is catalyzed by hydrogen ions. The rate of reaction increases with an increase in the amount of acetic acid in the solvent. The correlation analyses of the rate of oxidation of thirty-six aldehydes were performed in terms of Charton's LDR and LDRS equations. The rate of oxidation of meta- and para-substituted benzaldehydes showed excellent correlation with Charton's LDR equation. The rates of ortho-compounds showed excellent correlation with LDRS equation. The oxidation para-compounds is more susceptible to the delocalization effect. The oxidation of ortho- and meta-compounds exhibited a greater dependence on the field effect. The polar reaction constants are negative indicating an electron-deficient centre in the rate-determining step. A mechanism involving a nucleophilic attack on the carbonyl group by a permanganate-oxygen and a subsequent hydride transfer has been proposed.
- Purohit, Trupti,Banerji, Jayshree,Kotai, Laszlo,Sajo,Banerji,Sharma, Pradeep K.
-
p. 1045 - 1052
(2013/01/14)
-
- Continuous flow synthesis of secondary amides by tandem azidation-amidation of anilines
-
The continuous flow synthesis of a variety of secondary amides by tandem azidation-amidation of anilines is described. This new procedure benefits from the improved safety feature of generating aromatic azides in flow, thus ensuring low concentrations of any potentially hazardous intermediates. The protocol was amenable to the production of multi-gram quantities of the amide product. Georg Thieme Verlag Stuttgart · New York.
- Spiteri, Christian,Moses, John E.
-
experimental part
p. 1546 - 1548
(2012/08/07)
-
- Bio-inspired flavonol and quinolone dioxygenation by a non-heme iron catalyst modeling the action of flavonol and 3-hydroxy-4(1H)-quinolone 2,4-dioxygenases
-
The mononuclear complex, FeIII(O-bs)(salen) (salenH2 = 1,6-bis(2-hydroxyphenyl)-2,5-diaza-hexa-1,5-diene; O-bsH = O-benzoylsalicylic acid) was synthesized as synthetic enzyme-depside complex, and characterized by spectroscopic methods and X-ray crystal analysis. The dioxygenation of flavonol (flaH) and 3-hydroxy-4-quinolone (quinH2) derivatives in the presence of catalytic amounts of FeIII(O-bs)(salen) results in the oxidative cleavage of the heterocyclic ring to give the corresponding O-benzoylsalicylic and anthranilic acid derivatives with concomitant release of carbon monoxide. These reactions can be regarded as biomimetic functional models with relevance to the iron-containing flavonol and the cofactor-independent 3-hydroxy-4(1H)-quinolone 2,4-dioxygenases.
- Pap, József S.,Matuz, Andrea,Baráth, Gábor,Kripli, Balázs,Giorgi, Michel,Speier, Gábor,Kaizer, József
-
experimental part
p. 15 - 21
(2012/06/15)
-
- Structure-Reactivity correlation in the oxidation of substituted benzaldehydes by tetraethylammonium chlorochromate
-
Oxidation of 36 monosubstituted benzaldehydes by tetraethylammonium chlorochromate in dimethyl sulphoxide, leads to the formation of corresponding benzoic acids. The reaction is of first order with respect to chlorochromate and aldehydes. The reaction is promoted by H+; the H+ dependence has the form kobs = a + b[H+]. The oxidation of duteriated benzaldehyde exhibits substantial primary kinetic isotope effect. The reaction was studied in 19 different organic solvents and the effect of solvent was analyzed using Taft's and Swain's multiparametric equations. The rates of the oxidation of para- and meta-substituted benzaldehydes showed excellent correlation in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes were correlated well with tetraperametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalized effect than is the oxidation of ortho- and meta- substituted compounds, which display a greater dependence on the field effect. The positive value of h suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the orthosubstituents. A suitable mechanism has been proposed.
- Gehlot,Prasadrao,Sharma
-
experimental part
p. 1173 - 1178
(2012/01/05)
-
- Iron-doped single-walled carbon nanotubes as new heterogeneous and highly efficient catalyst for acylation of alcohols, phenols, carboxylic acids and amines under solvent-free conditions
-
Iron-doped single-walled carbon nanotubes (Fe/SWCNTs) represent an efficient and new heterogeneous reusable catalyst for the acylation of a variety of alcohols, phenols, carboxylic acids and amines with acid chlorides or acid anhydrides under solvent-free conditions. The reactions of various primary, secondary, tertiary, and benzylic alcohols, diols, phenols, as well as aromatic and aliphatic amines give acylated adducts in good to excellent yields.
- Sharghi, Hashem,Jokar, Mahboubeh,Doroodmand, Mohammad Mahdi
-
experimental part
p. 426 - 442
(2011/04/15)
-
- Quinazolin-4(3A)-One Derivatives and Methods of Use Thereof
-
Provided are quinazolin-4(3A)-one derivatives, which are inhibitors of the ubiquitin ligase activity of a human polypeptide, particularly to POSH inhibitors, and to compositions and methods for the treatment RING E3 ubiquitin ligase related diseases.
- -
-
Page/Page column 9
(2011/06/23)
-
- "Meta elimination," a diagnostic fragmentation in mass spectrometry
-
The diagnostic value of the "ortho effect" for unknown identification by mass spectrometry is well known. Here, we report the existence of a novel "meta effect," which adds to the repertoire of useful mass spectrometric fragmentation mechanisms. For example, the meta-specific elimination pathway described in this report enables unequivocal identification of meta isomers from ortho and para isomers of carboxyanilides. The reaction follows a specific path to eliminate a molecule of meta-benzyne, from the anion produced after the initial decarboxylation of the precursor. Consequently, in the CID spectra of carboxyanilides, a peak for the (R-CO-NH)- anion is observed only for the meta isomers. For example, the peaks observed at m/z 58, 86, 120, 128, and 170 from acetamido-, butamido-, benzamido, heptamido-, and decanamido-benzoates, respectively, were specific only to the spectra of meta isomers.
- Attygalle, Athula B.,Nishshanka, Upul,Weisbecker, Carl S.
-
experimental part
p. 1515 - 1525
(2012/05/05)
-
- Kinetics and products of the catalytic oxidation of acetamidotoluenes with ozone in acetic acid
-
The kinetics of acetamidotoluene oxidation in glacial acetic acid in the presence of cobalt acetate is reported. At 95°C and atmospheric pressure, acetamidotoluenes are oxidized by molecular oxygen very slowly: oxidation is complete in 10-12 h, and the major reaction products are acetamidobenzoic acids (27-36% yield). The introduction of ozone into the reactive gas increases the reaction rate by one order of magnitude. The main role of ozone is to generate the active form of the catalyst.
- Galstyan,Bushuev,Sementsov
-
experimental part
p. 516 - 520
(2011/01/07)
-
- Synthetic applications of Pd(II)-catalyzed C-H carboxylation and mechanistic insights: Expedient routes to anthranilic acids, oxazolinones, and quinazolinones
-
A Pd(II)-catalyzed reaction protocol for the carboxylation of ortho-C-H bonds in anilides to form N-acyl anthranilic acids has been developed. This reaction procedure provides a novel and efficient strategy for the rapid assembly of biologically and pharmaceutically significant molecules, such as benzoxazinones and quinazolinones, from simple anilides without installing and removing an external directing group. The reaction conditions are also amenable to the carboxylation of N-phenyl pyrrolidinones. A monomeric palladacycle containing p-toluenesulfonate as an anionic ligand has been characterized by X-ray crystallography, and the crucial role of p-toluenesulfonic acid in the activation of C-H bonds in the presence of carbon monoxide is discussed. Identification of two key intermediates, a mixed anhydride and benzoxazinone formed by reductive elimination from organometallic Ar(CO)Pd(II)-OTs species, provides mechanistic evidence for a dual-reaction pathway.
- Giri, Ramesh,Lam, Jonathan K.,Yu, Jin-Quan
-
supporting information; experimental part
p. 686 - 693
(2010/03/25)
-
- Syntheses and antimicrobial activities of derivatives of 3-amino-2-methyl-quinazolin-4-(3H)-one
-
In the present study, 3-amino-2-methyl-quinazolin-4-(3H)-one (1) have been synthesized by the reaction of N-acetyl anthranilic acid with acetic anhydride followed by treating the mixture with hydrazine hydrate in pyridine. Compound 1 on treating with chloro acetyl chloride gives 3-chloroethanoylamino-2-methyl-quinazolin-4-(3H)-one (2). The final compounds 4a-g were obtained by reacting the substituted derivative 2 with aliphatic and aromatic secondary amines. The structural assignment of this compound 4a-g has been made on the basis of elemental analysis, IR and 1H NMR data. The synthesized compounds were screened for in vitro growth inhibiting activity by determining the minimum inhibitory concentration against different strains of bacteria and fungi. Compounds 4a, 4b, 4e and 4g exhibit highest antibacterial activity and compounds 4a, 4b, 4d and 4e showed better antifungal activity.
- Chhabra,Tiwari, Ravi
-
experimental part
p. 3390 - 3396
(2010/11/17)
-
- Synthesis, antimalarial and antibacterial activities of 3-amino acid- and aryl amine-substituted 2-methyl- 3H-quinalzolin-4-ones
-
A new series of 2-methyl-3H-quinazolinones substituted at the third position with amino acids (2-5) and aryl amine (6, 7) was designed, synthesized, and analyzed by infrared, NMR, and mass spectral analysis. Further, the compounds were screened for their in vivo antimalarial activity using the rodent malaria parasite Plasmodium yoelii (N-67) with the Swiss mice model. The compounds were also tested for their antibacterial activity. Birkhaueser Boston 2009.
- Nainar Meyyanathan, Subramania,Ramu, Mamillapalli,Suresh, Bhojraj
-
experimental part
p. 993 - 999
(2011/12/01)
-
- Practical and chemoselective reduction of acyl chloride to alcohol by borohydride in aqueous dichloromethane
-
A simple methodology for the reduction of acid chlorides to their corresponding alcohols has been developed. Various carboxylic acids were converted to alcohols in excellent yields using NaBH4-K2CO3 in a mixed solvent system of dichloromethane and water (1:1) in the presence of a phase-transfer catalyst at low temperature. The importance of the work is its simplicity, selectivity, excellent yield, and very short reaction time. This new reduction condition has proved to be an excellent chemoselective method for a range of acid chlorides in the presence of various functional groups.
- Rajan, Ramya,Badgujar, Sachin,Kaur, Kamaljit,Malpani, Yashwardhan,Kanjilal, Pranab R.
-
experimental part
p. 2897 - 2907
(2010/11/18)
-
- Metal acetate/metal oxide in acetic acid: An efficient reagent for the chemoselective N-acetylation of amines under green conditions
-
The use of catalytic amount of metal acetate or metal oxide in acetic acid is a new and highly efficient acetylating system for chemoselective N-acetylation of primary and secondary amines in excellent yields under reflux condition. No other solvent is required. The noted features of this method include mild reaction conditions, use of innocuous reagents, excellent yields, convenient work-up, and reuse of catalyst.
- Brahmachari, Goutam,Laskar, Sujay,Sarkar, Sajal
-
experimental part
p. 288 - 295
(2010/10/18)
-
- A green approach to chemoselective N-acetylation of amines using catalytic amount of zinc acetate in acetic acid under microwave irradiation
-
It has been found for the first time that zinc acetate alone can act as a selective A'-acetylating agent without any solvent under closed vessel microwave irradiation. It is also observed that the use of a catalytic amount of this reagent in acetic acid is sufficient enough for smooth running of A'-acetylation of a number of structurally diverse amines, and the reaction is chemoselective with respect to phenols, thiols, acids and alcohols. Herein is reported a simple, efficient, cost-effective and environmentally benign alternative method for chemoselective A'-acetylation of amines using catalytic amount of zinc acetate in acetic acid under microwave irradiation. The reaction procedure requires no other solvent, and is rapid with good to excellent yields.
- Brahmachari,Laskar,Sarkar
-
experimental part
p. 1274 - 1281
(2010/12/24)
-
- Correlation analysis of reactivity in the oxidation of substituted benzaldehydes by morpholinium chlorochromate
-
Oxidation of thirty six monosubstituted benzaldehydes by morpholinium chlorochromate (MCC) in dimethylsulphoxide (DMSO), leads to the formation of corresponding benzoic acids. The reaction is of first order with respect to MCC. A Michaelis-Menten type kinetics is observed with respect to benzaldehydes. The reaction is promoted by hydrogen ions; the hydrogen-ion dependence has the form kobs = a + b [H+]. The oxidation of [2H] benzaidehyde (PhCDO) exhibited a substantial primary kinetic isotope effect. The reaction was studied in nineteen organic solvents and the effect of solvent was analysed using Taft's and Swain's multi-parametric equations. The rates of the oxidation of para- and meta-substituted benzaldehydes showed excellent correlation in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes were correlated well with tetraparametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalized effect than is the oxidation of ortho- and meta-substituted compounds, which display a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the ortho-substituents. A suitable mechanism has been proposed.
- Choudhary, Anurag,Malani,Agarwal,Sharma,Sharma, Vinita
-
experimental part
p. 927 - 935
(2010/07/16)
-
- Dioxygenase-Mediated Quenching of Quinolone-Dependent Quorum Sensing in Pseudomonas aeruginosa
-
2-Heptyl-3-hydroxy-4(1H)-quinolone (PQS) is a quorum-sensing signal molecule used by Pseudomonas aeruginosa. The structural similarity between 3-hydroxy-2-methyl-4(1H)-quinolone, the natural substrate for the 2,4-dioxygenase, Hod, and PQS prompted us to i
- Pustelny, Christian,Albers, Alexander,Bueldt-Karentzopoulos, Klaudia,Parschat, Katja,Chhabra, Siri Ram,Camara, Miguel,Williams, Paul,Fetzner, Susanne
-
experimental part
p. 1259 - 1267
(2010/07/10)
-
- Synthesis and biological evaluation of some anthranilic acid and 2-phenylquinazoline-4(3H)-one analogues
-
In the present investigation a novel series of N-(phenyl) chalconyl anthranilic acids containing pyrazolines (4a-j), tetra- hydropyrimidines (4k-o), tetrahydrothiopyrimidines (4p-t) and 2-phenylquinazolin-4(3iJ)-ones containing pyrazolines (8a-f), isoxazolines (8g-l), tetrahydropyrimidines (8m-r) and tetrahydrothiopyrimidines (8s-x) were synthesized and characterized by elemental analysis, FT-IR, 1H NMR and mass spectroscopy. The title compounds (4a-t) and (8a-x) were investigated for their analgesic, anti-inflammatory, antimicrobial and in vitro protein denaturation activities. Compounds 4j and 8x were identified as lead compounds with optimum analgesic, anti-inflammatory and antimicrobial activities.
- Banerjee, Mrityunjay,Behera, Chinmoy C.,Pradhan, Guru C.,Azam, M. Afzal,Sahu, Susant K.
-
scheme or table
p. 134 - 142
(2010/08/07)
-
- Structure-reactivity correlation in the oxidation of substituted benzaldehydes by 2,2-bipyridinium chlorochromate
-
Oxidation of thirty six monosubstituted benzaldchydes by 2,2′-bipyridiniuin chlorochromate (BPCC) in diniethylsulphoxide (DMSO), leads to the formation of corresponding benzoic acids. The reaction is of first order with respect to both BPCC and aldehydes. The reaction is promoted by hydrogen ions; the hydrogen ion dependence has the form kobs= a + b[H+]. The oxidation of [2H]benzaldehyde (PhCDO) exhibited a substantial primary kinetic isotope effect. The reaction was studied in nineteen different organic solvents and the effect of solvent was analysed using Taft's and Swain's multi-parametric equations. The rates of the oxidation of para- and mete-substituted benzaldehydes showed excellent correlation in terms of Charton's triparametric LDR equation, whereas the oxidation of orfAo-substituted benzaldehydes were correlated well with tetraparametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalized effect than is the oxidation of ortho- and mem-substituted compounds, which display a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the ortho-substituents. A suitable mechanism has been proposed.
- Sharma, Pradeep K.
-
experimental part
p. 1281 - 1288
(2009/12/31)
-
- Electrochemical nuclear acetamidation of aromatic compounds at the platinum anode
-
The electrochemical nuclear acetamidation of aromatic compounds ethylbenzoate, acetophenone, benzoic acid and benzene have been carried out at platinum anode under the process of nuclear oxidation. The removal of electrons from the aromatic π-electron system is achieved by the electrochemical oxidation. The electrolysis is carried out at the constant anode potential in an electrolytic cell assembly containing reaction mixture and electrodes. The products 4-acetamidoethylbenzoate, 4-acetamidoacetophenone, 4-acetamidobenzoic acid and N-phenylacetamide formed during the electrolysis are reported here.
- Sharma, Laxmi Kant,Kumar, Sanjeev,Yadav, Pragati,Singh
-
p. 1277 - 1280
(2008/12/23)
-
- New, efficient, selective, and one-pot method for acylation of amines
-
Hydrazine hydrate with acetic and propionic acids was an efficient reagent for acylation of primary and secondary amines at reflux temperatures. The reported one-pot method is high-yielding, simple, mild, and inexpensive. Copyright Taylor & Francis Group, LLC.
- Basanagouda, Mahantesha,Kulkarni, Manohar V.,Kalkhambkar, Raj G.,Kulkarni, Geeta M.
-
p. 2929 - 2940
(2008/12/22)
-
- Kinetics and mechanism of the oxidation of substituted benzaldehydes by tetrabutylammonium tribromide
-
The oxidation of thirty-six monosubstituted benzaldehydes by tetrabutylammonium tribromide (TBATB), in aqueous acetic acid solution, leads to the formation of the corresponding benzoic acids. The reaction is first order with respect to both TBATB and aldehydes. The reaction failed to induce the polymerization of acrylonitrile. There is no effect of tetrabutylammonium chloride ions on the reaction rate. The oxidation of [2H]benzaldehyde (PhCDO) indicated the presence of a substantial kinetic isotope effect. The effect of solvent composition indicated that the reaction rate increases with an increase in the polarity of the medium. The rates of oxidation of meta- and para-substituted benzaldehydes showed excellent correlations in terms of Charton's triparametric LDR equation whereas the oxidation of ortho-substituted benzaldehydes correlated well with tetraparametric LDS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalization effect but the oxidation of ortho- and meta-substituted compounds displayed a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction center in the rate-determining step. The reaction is subjected to steric acceleration when ortho-substituents are present.
- Chouhan,Sharma, Monica,Sharma, Vinita
-
p. 582 - 587
(2008/09/21)
-
- THIAZOLE AND THIOPHENE ANALOGUES, AND THEIR USE IN TREATING AUTOIMMUNE DISEASES AND CANCERS
-
Thiazole and thiophene compounds are disclosed having utility in treating inflammatory conditions, immunoinflammatory conditions, autoimmune diseases, and cancers. Methods for the synthesis of these compounds are also disclosed.
- -
-
Page/Page column 47
(2008/06/13)
-
- Oxidative cleavage reaction of substituted indoles catalyzed by plant cell cultures
-
We have developed a novel method for the oxidative cleavage of indole carbon double bonds in the presence of H2O2 using plant cell cultures as peroxidase. The oxidative method has some advantage, as features such as mild reactions, good yields, easy work-up and safety.
- Takemoto, Masumi,Iwakiri, Yasutaka,Tanaka, Kiyoshi
-
p. 373 - 383
(2008/03/12)
-
- Hydrogen processing by FeIII-exchanged montmorillonite: A unique geochemical protocol
-
The production of hydrogen by the relay of electrons from 1- to H+ in an acidic, aqueous medium and the consumption of hydrogen by reductive N acylation open up enormous opportunities in hydrogen chemistry (see scheme).
- Choudary, Boyapati M.,Kantam, Mannepalli L.,Ranganath, Kalluri V. S.,Rao, Kottapalli K.
-
p. 322 - 325
(2007/10/03)
-
- A new synthesis of 2-substituted 4H-3,1-benzoxazin-4-ones by cyanuric chloride cyclodehydration of N-benzoyl- and N-acylanthranilic acids
-
A new and a convenient method for the synthesis of aryl- and alkyl-2-substituted 4H-3,1-benzoxazin-4-ones by cyclodehydration of N-benzoyl- and N-acylanthranilic acid by cyanuric chloride is described.
- Khajavi, Mohammad S.,Shariat, Seyed M.
-
p. 1159 - 1165
(2007/10/03)
-
- Mechanism of Photoinduced Reactions between 1-Acetylisatin and Aldehydes
-
Hydrogen atom abstraction from aliphatic (2a, 2b) and aromatic (2c, 2d, 2e) aldehydes by the triplet nπ* state of 1-acetylisatin (1) yielded triplet (isatin ketyl-aldehyde acyl) radical pairs, which follow an out-of-cage pathway in subsequent reactions to give a series of radical coupling products 4-7. This out-of-cage mechanism is supported by examination of the primary products at various degrees of conversions during the course of the reaction, by the results of addition reactions of thermally generated isatin acyl radical with neutral 1, and by calculation of the charge density distribution in the acyl radicals and in ground state 1. Therefore, the oxygen-philic attack of the acyl radical, which had escaped out of cage from the triplet radical pair, at the C(3) carbonyl oxygen atom of a ground state 1 selectively afforded the thermodynamically more stable addition radical B. The recombination of two radicals B gave the 3-indolinone dimers 4 and 5 as diastereomers, while coupling of B with the isatin ketyl furnished the dihydroisoindigo derivative 6. Isatide 7 was also formed by ketyl radical recombination. The product ratio is dependent on the structure of the aldehyde. For 2d and 2e, each with an electron-donating substituent in the benzene ring, the corresponding acyl radicals are less electrophilic because of a diminished positive charge density at the carbonyl carbon atom, and the formation of the addition radical B is a slow process relative to the encounter and recombination of the isatin ketyl radicals. As a result, products 6d and 6e from cross-coupling of the isatin ketyl and radical B are formed in much lower yields than 6a, 6b, and 6c. The 3-acetyloxy-2-indolinone 3 turned out to be a secondary product derived from the decomposition of 6 during the workup procedures. Since all the primary products are formed by out-of-cage radical pair combination processes, no chain mechanism is involved. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Zhang, Yan,Wang, Lei,Zhu, Ye,Xu, Jian-Hua
-
p. 527 - 534
(2007/10/03)
-
- METHOD OF PROCESSING OF HYDROGEN FOR REDUCTIVE ACYLATION OF NITRO, AZIDO AND CYANO ARENES
-
The present invention relates to a method for processing of hydrogen for the reductive acylation of nitro, azido and cyano arenes. More particularly, this invention relates to an improved process for the preparation of amides and anilides using C3-C7 carboxylic acids as proton source/acylating agents employing Fe3+-montmorillonite as a catalyst.
- -
-
-