- Anti-tubercular activity and molecular docking studies of indolizine derivatives targeting mycobacterial InhA enzyme
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A series of 1,2,3-trisubstituted indolizines (2a–2f, 3a–3d, and 4a–4c) were screened for in?vitro whole-cell anti-tubercular activity against the susceptible H37Rv and multidrug-resistant (MDR) Mycobacterium tuberculosis (MTB) strains. Compounds 2b–2d, 3a
- Venugopala, Katharigatta N.,Chandrashekharappa, Sandeep,Deb, Pran Kishore,Tratrat, Christophe,Pillay, Melendhran,Chopra, Deepak,Al-Shar’i, Nizar A.,Hourani, Wafa,Dahabiyeh, Lina A.,Borah, Pobitra,Nagdeve, Rahul D.,Nayak, Susanta K.,Padmashali, Basavaraj,Morsy, Mohamed A.,Aldhubiab, Bandar E.,Attimarad, Mahesh,Nair, Anroop B.,Sreeharsha, Nagaraja,Haroun, Michelyne,Shashikanth, Sheena,Mohanlall, Viresh,Mailavaram, Raghuprasad
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p. 1472 - 1487
(2021/07/10)
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- Silver-Promoted (4 + 1) Annulation of Isocyanoacetates with Alkylpyridinium Salts: Divergent Regioselective Synthesis of 1,2-Disubstituted Indolizines
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An unprecedented silver-promoted regioselective (4 + 1) annulation of isocyanoacetates with pyridinium salts is reported. The established protocol provides controlled, facile, and modular access to a range of synthetically useful N-fused heterocyclic scaffolds containing indolizines, pyrrolo[1,2-a]quinolines, pyrrolo[2,1-a]isoquinolines, and 1H-imidazo[4,5-a]indolizin-2(3H)-ones. A mechanistic pathway involving nucleophilic addition/protonation/elimination/cycloisomerization is proposed.
- Chen, Yan,Shatskiy, Andrey,Liu, Jian-Quan,K?rk?s, Markus D.,Wang, Xiang-Shan
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supporting information
p. 7555 - 7560
(2021/10/02)
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- Ultrasound-promoted regioselective synthesis of chalcogeno-indolizines by a stepwise 1,3-dipolar cycloaddition
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A series of new organochalcogen derivatives of indolizines was synthesized in moderate to excellent yields from pyridinium salts and chalcogeno-alkynes. The reaction can be carried out under thermal conditions or by sonochemical processes in short reaction times. The stepwise cycloaddition reaction forming chalcogeno-indolizines is regioselective and extends to a broad range of functional groups. Furthermore, novel chalcogeno-alkynes are reported and the first derivatives of teluro-indolizine are described. The influence of selenium functionalization on the photophysical properties of indolizines is also described, in which the compounds showed absorption in the UV–Vis region around 360 nm and emission in the blue-to-green region. Relatively low fluorescence quantum yield (?fl) values were calculated, in agreement with the chalcogen effect on other heterocycles.
- Vieira, Marcelo M.,Dalberto, Bianca T.,Coelho, Felipe L.,Schneider, Paulo H.
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- An efficient microwave accelerated three component reaction of phenacyl azides and pyridinium phenacyl salts: A facile greener approach to 2-amino-2-ene-1,4-diones/pyrrolidin-2-ones
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A mild and efficient base promoted, microwave assisted, green synthesis of 2-amino-2-ene-1,4-diones has been described by the decomposition of phenacyl azides followed by treatment with pyridinium salts of phenacyl bromides in aqueous media. A diverse range of substrates bearing electron-releasing and electron-withdrawing substituents were well tolerated and delivered corresponding 2-amino-2-ene-1,4-diones in good yields. Synthesized 2-amino-2-ene-1,4-diones have been further explored in the synthesis of various substituted 4-hydroxypyrrolidin-2-ones.
- Chimaladenne, Venkateswarlu,Manda, Ramesh,Gudipally, Ashok Reddy,Valluru, Krishna Reddy,Brahman, Pradeep Kumar,Somarapu, Vijaya Laxmi
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p. 2941 - 2949
(2020/07/30)
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- DMAP-Catalyzed Annulation Approach for Modular Assembly of Furan-Fused Chromenes
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With a tandem DMAP-catalyzed reaction between o-AQM, in which it is generated in situ from propargylic amine, and acyl carbene surrogate (from pyridinium ylide), a variety of polyarylated chromenes are assembled in good yields. This process does not require transition-metal catalyst and exhibits easy manipulation of the arene group and good functional group compatibility, particularly the -Br group which can be further transformed to other functionalities by cross-coupling reactions. The modular feature of o-AQM substrates and the simple operation procedures add further advantages to this synthetic method.
- He, Xinwei,Li, Ruxue,Choy, Pui Ying,Liu, Tianyi,Wang, Junya,Yuen, On Ying,Leung, Man Pan,Shang, Yongjia,Kwong, Fuk Yee
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supporting information
p. 9444 - 9449
(2020/12/21)
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- A metal-free approach for the synthesis of amides/esters with pyridinium salts of phenacyl bromides via oxidative C–C bond cleavage
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An efficient, simple, and metal-free synthetic approach for the N- and O-benzoylation of various amines/benzyl alcohols with pyridinium salts of phenacyl bromides is demonstrated to generate the corresponding amides and esters. This protocol facilitates the oxidative cleavage of a C–C bond followed by formation of a new C–N/C–O bond in the presence of K2CO3. Various pyridinium salts of phenacyl bromides can be readily transformed into a variety of amides and esters which is an alternative method for the conventional amidation and esterification in organic synthesis. High functional group tolerance, broad substrate scope and operational simplicity are the prominent advantages of the current protocol.
- Manasa, Kesari Lakshmi,Tangella, Yellaiah,Krishna, Namballa Hari,Alvala, Mallika
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supporting information
p. 1864 - 1871
(2019/08/12)
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- Microwave-assisted quaternization of various pyridine derivatives and their antibacterial activity
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In this study, reactions of quaternization under microwave heating of pyridine, α-picoline, pyridine-4-aldoxime, pyridine-2-aldoxime, nicotinamide, isonicotinamide and pyridoxal oxime with different electrophiles: 2-bromo-4'-nitroacetophenone, 2-amino-4-chloro-methylthiazole hydrochloride, methyl iodide, 1, 3-diiodopropane and 1, 3-dibromopropane are reported. The synthesis yield by microwave dielectric heating is improved and reaction time shortened compared to conventional heating. The structure of obtained molecules were analyzed and determined by 1D and 2D NMR spectroscopy methods, IR spectroscopy and mass spectrometry. The highest antibacterial activity against two Gram-positive and two Gram-negative bacteria strains has been found for 1-[2-(4-nitrophenyl)-2-oxoethyl]pyridinium bromide (2).
- Bu?i?, Valentina,Pavlovi?, Hrvoje,Roca, Sun?ica,Viki?-Topi?, Dra?en,Ga?o-Soka?, Dajana
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p. 425 - 433
(2018/01/26)
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- Facile one-pot tandem synthesis of perfluoroalkylated indolizines under metal-free mild conditions
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A direct metal-free method for the synthesis of perfluoroalkylated indolizines by means of DIPEA-promoted tandem C[sbnd]N/C[sbnd]C bond formation was developed. Various substituted pyridines and bromoacetyl derivatives with methyl perfluoroalk-2-ynoates proceeded smoothly in this mild transformation, and the desired products were obtained in good to excellent yields under air.
- He, Dong,Xu, Yuhong,Han, Jing,Deng, Hongmei,Shao, Min,Chen, Jie,Zhang, Hui,Cao, Weiguo
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p. 938 - 944
(2017/01/25)
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- Transition-Metal-Free Synthesis of Indolizines from Electron-Deficient Alkenes via One-Pot Reaction Using TEMPO as an Oxidant
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A one-pot method for the synthesis of multisubstituted indolizines from α-halo carbonyl compounds, pyridines, and electron-deficient alkenes is reported. The oxidative dehydrogenation reaction takes place under transition-metal-free conditions using TEMPO as an oxidant. This protocol uses ready available starting materials in a convenient procedure under mild reaction conditions.
- Shi, Fei,Zhang, Yu,Lu, Zhaole,Zhu, Xiaolei,Kan, Weiqiu,Wang, Xiang,Hu, Huayou
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p. 413 - 420
(2016/01/28)
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- Greener synthesis of indolizine analogues using water as a base and solvent: study for larvicidal activity against Anopheles arabiensis
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Greener synthesis of a series of novel indolizine analogues have been achieved by the cyclization of aromatic cycloimmonium ylides with electron-deficient alkynes in the presence of water as the base and solvent at 80?°C. Yield of the title compounds was
- Sandeep, Chandrashekharappa,Venugopala, Katharigatta N.,Gleiser, Raquel M.,Chetram, Abeen,Padmashali, Basavaraj,Kulkarni, Rashmi S.,Venugopala, Rashmi,Odhav, Bharti
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p. 899 - 904
(2016/11/11)
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- One-pot synthesis of indolizine via 1,3-dipolar cycloaddition using a sub-equivalent amount of K2Cr2O7 as an efficient oxidant under base free conditions
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A one-pot method for synthesizing multi-substituted indolizines from α-halo-carbonyl compounds, pyridines and electron deficient alkenes was developed. A sub-equivalent amount of potassium dichromate was used as an oxidant under base free conditions. The transformation developed should be of economic efficiency.
- Wang, Chao,Hu, Huayou,Xu, Juanfang,Kan, Weiqiu
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p. 41255 - 41258
(2015/05/20)
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- SMALL MOLECULE C-MYC INHIBITORS
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This invention provides small molecule Myc-inhibitors. Also provided in the invention are therapeutic applications of these compounds for treating Myc-driven cancer and other related methods.
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Paragraph 0065
(2015/06/25)
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- Microwave-assisted, one-pot three component synthesis of 2-phenyl H-imidazo[1, 2-α]pyridine
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A novel synthesis of 2-phenylH-imidazio[1, 2-α] pyridines is described from a one-pot, three-component reaction between pyridine, guanidine (urea or thiourea) and α-bromoketones under microwave irradiation and solvent-free conditions in excellent yields.
- Motevalli, Kourosh,Yaghoubi, Zahra,Mirzazadeh, Roghieh
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experimental part
p. 1047 - 1052
(2012/06/01)
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- Copper acetate monohydrate: A cheap but efficient oxidant for synthesizing multi-substituted indolizines from pyridinium ylides and electron deficient alkenes
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We report a highly practical one-pot method for synthesizing multi-substituted indolizines from ?±-halide carbonyl compounds, pyridines and electron deficient alkenes in the presence of copper acetate monohydrate and sodium acetate in DMF. A variety of function groups are tolerable in standard reaction conditions, including aldehyde. 36 examples were presented. The yield of indolizine was from moderate to high. Furthermore, multi-substituted indolizines can be prepared at gram scale by this method.
- Hu, Huayou,Feng, Junjun,Zhu, Yulan,Gu, Ning,Kan, Yuhe
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p. 8637 - 8644
(2015/02/19)
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- Stability of 1-phenacylpyridinium and 1-(2-hydroxy-2-phenylvinyl)pyridinium cations
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1-Phenacylpyridinium cation, C5H5N+-CH2COC6H 4R-p, is the only tautomeric form detected in DMSO solution. This shows that the vicinity of the strong electron-acceptor pyridinium group has a minor effect on acidity of the methylene protons in 1-phenacylpyridinium salts. It was found that substitution in the benzene ring does not affect the tautomeric equilibrium. Although 1-(2-hydroxy-2-phenylvinyl)pyridinium cation is stabilized by conjugation, the ab initio calculated energies confirm the higher stability of the keto form (electron-acceptor substituents slightly increase stability of the enol form). It was found that 1-(2-hydroxy-2-phenylvinyl)pyridinium cation is not planar. Calculations show that electrostatic attraction between the onium nitrogen and hydroxy oxygen atoms takes place in this cation.
- Osmialowski,Janota,Gawinecki
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p. 169 - 177
(2007/10/03)
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- Kinetics and Mechanism of the Pyridinolysis of Phenacyl Bromides in Acetonitrile
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Kinetic studies of the reactions of substituted phenacyl bromides (YC6H4COCH2Br) with pyridines (XC5H4N) are carried out in acetonitrile at 45.0°C. A biphasic Bronsted plot is obtained with a change in slope from a large (βX ? 0.65-0.80) to a small (βX ? 0.36-0.40) value at pKao = 3.2-3.6, which can be attributed to a change in the rate-determining step from breakdown to formation of a tetrahedral intermediate in the reaction path as the basicity of the pyridine nucleophile increases. This mechanism is supported by the faster rates with pyridines than with anilines and the change of cross-interaction constant ρXY from a large positive (ρXY ? +1.4) to a small positive (ρXY ? +0.1) value. The large magnitude of Hammett ρX (= -5.5 to -6.9) values for the pyridines with electron-withdrawing substituents and positive deviations of the π-acceptors, p-CH3CO and p-CN, are quite similar to those for the pyridinium ion formation equilibria. The activation parameters are also in line with the proposed mechanism.
- Koh, Han Joong,Han, Kwang Lae,Lee, Hai Whang,Lee, Ikchoon
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p. 4706 - 4711
(2007/10/03)
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- Synthesis and Nitration of Some Thieno-fused Analogues of the Benzo[a]quinolizinium Cation
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Three thieno-fused analogues of benzo[a]quinolizinium (1), thieno[3,2-a]- and thieno[2,3-a]quinolizinimn 4 and 5 and thiazolo[2,3-a]isoquinolinium (6), were synthesized by photocyclization of 1-(2-thienylvinyl)pyridinium salts 9a and 9b and 3-styrylthiazolium salt 9c, respectively. The nitration of the compounds 4, 5, and 6 occurred predominantly at positions 2, 3, and 7, respectively, while the nitro group was introduced into the 8- and 10-positions of 1 in the ratio of 68:32. The nmr and uv spectral properties and reduction potentials of 4-6 were also compared with those of the parent compound 1.
- Sato, Kiyoshi,Arai, Sadao,Yamagishi, Takamichi
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- Synthesis of Novel Methoxy and Hydroxy Derivatives of 2-Phenyl-1H-benzindoles
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The synthesis of novel methoxy-derivatives of 2-phenyl-1H-benzindole 3 by condensation of α-naphthylamines 1 with N-phenacyl-pyridinium salts 2 is described, as well as their conversion into the corresponding hydroxy-derivatives 5.Unexpected quinoxaline derivatives 4 were obtained when in the condensation reaction the N-nitrophenacylpyridinium salts 2d,e have been used.
- Ferlin, Maria Grazia,Chiarelotto, Gianfranco,Malesani, Giorgio
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p. 245 - 249
(2007/10/02)
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- SYNTHESIS AND STRUCTURAL STUDY ON Α-SUBSTITUED-1-STYRYLPYRIDINIUM SALTS. REINVESTIGATION OF KROHNKE CONDENSATION
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Kroehnke condensation of several cycloimmonium salts with p-dimethylaminobenzaldehyde has been studied.X-Ray diffraction, IR and Raman spectra, 1H- and 13C-NMR and UV spectra of the products are discussed, being compared, when necessary, with the starting pyridinium salts.All compounds showed the Z configuration, corresponding to the more stable structure, except one, in which steric factors were predominant.
- Alvarez-Builla, J.,Novella, J. L.,Galvez, E.,Smith, P.,Florencio, F.,et al.
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p. 699 - 708
(2007/10/02)
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