- SYNTHESIS OF o-ACYLAMINO-4-METHYL-7-HYDROXYCOUMARINS (4-METHYLUMBELLIFERONES)
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Some acylated o-amino-7-hydroxycoumarins have been obtained which may be used as intermediates in the preparation of fluorogenic substrates for certain enzymes.
- Kozlova, I. K.
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- Novel 4-methylumbelliferone amide derivatives: Synthesis, characterization and pesticidal activities
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A series of novel 4-methylumbelliferone amide derivatives were designed, synthesized and characterized by 1H NMR, 13C NMR and HR-ESI-MS. The structures of compounds 4bd and 4be (compounds named by authors) were further confirmed by X-ray single crystal diffraction. The acaricidal, herbicidal and antifungal activities of the synthesized compounds were assayed for their potential use as pesticide. The results indicated that compounds 4bi, 4ac and 4bd were strong acaricidals against Tetranychus cinnabarinus, with 72h corrected mortalities of greater than 80% at 1000 mg/L. Meanwhile, compounds 4bh and 4bf exhibit the strongest inhibition against the taproot development of Digitaria sanguinalis and Chenopodium glaucum, and were even more potent than the commercial herbicide Acetochlor against D. sanguinalis. In addition, compounds 4bk, 4bh and 4bp showed the highest antifungal activity against the mycelium growth of Valsa Mali, which makes them more effective than commercial fungicide Carbendazim.
- Wei, Yan,Miao, Kai-Long,Hao, Shuang-Hong
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- Anti-inflammatory screening and molecular modeling of some novel coumarin derivatives
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Coumarin and their derivatives have drawn much attention in the pharmacological and pharmaceutical fields due to their broad range and diverse biological activities. In the present work, starting from the 6-amino-7-hydroxy-4-methyl-2H-chromen-2-one, a series of 6-(substituted benzylamino)-7-hydroxy-4-methyl-2H-chromen-2-ones 1-11 was synthesized and assessed for their anti-inflammatory activity using the carrageenan-induced hind paw edema method. Compounds 2, 3, 4 and 9 showed significant (p 0.001) reduction of rat paw edema volume after 1 h from the administration of the carrageenan compared to the reference drug, indomethacin. On the other hand, compounds 4 and 8 showed the highest anti-inflammatory activity, surpassing indomethacin after 3 h with 44.05% and 38.10% inhibition, respectively. Additionally, a molecular docking study was performed against the COX enzyme using the MOE 10.2010 software.
- El-Haggar, Radwan,Al-Wabli, Reem I.
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- Regioselective mononitration of coumarins using chromium nitrate as nitrating agent
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A very efficient and simple method is presented for the regio-selective mononitration of coumarins, using chromium nitrate in acetic anhydride, in high yields at room temperature.
- Bansal, Vandana,Khanna
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- Mono-nitration of Coumarins by Nitric Oxide
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A novel methodology for the efficient and selective nitration of coumarins has been developed. The reaction of coumarins containing a hydroxy group with nitric oxide in CH2Cl2 or CH3CN gave aromatic mono- and regio-specifi
- Lei, Liandi,Yang, Desuo,Liu, Zhongquan,Wu, Longmin
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- Light-Controlled Tyrosine Nitration of Proteins
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Tyrosine nitration of proteins is one of the most important oxidative post-translational modifications in vivo. A major obstacle for its biochemical and physiological studies is the lack of efficient and chemoselective protein tyrosine nitration reagents. Herein, we report a generalizable strategy for light-controlled protein tyrosine nitration by employing biocompatible dinitroimidazole reagents. Upon 390 nm irradiation, dinitroimidazoles efficiently convert tyrosine residues into 3-nitrotyrosine residues in peptides and proteins with fast kinetics and high chemoselectivity under neutral aqueous buffer conditions. The incorporation of 3-nitrotyrosine residues enhances the thermostability of lasso peptide natural products and endows murine tumor necrosis factor-α with strong immunogenicity to break self-tolerance. The light-controlled time resolution of this method allows the investigation of the impact of tyrosine nitration on the self-assembly behavior of α-synuclein.
- Long, Tengfang,Liu, Lei,Tao, Youqi,Zhang, Wanli,Quan, Jiale,Zheng, Jie,Hegemann, Julian D.,Uesugi, Motonari,Yao, Wenbing,Tian, Hong,Wang, Huan
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supporting information
p. 13414 - 13422
(2021/05/12)
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- Synthesis and biological evaluation of coumarin clubbed thiazines scaffolds as antimicrobial and antioxidant
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A new series of 4-methyl-6-nitro-2-oxo-2H-chroman-7yl-2-(4-(4-fluorophenyl)-6-phenyl-2H-1,3-thiazin-2-yl-amino)acetates 5a–j were synthesized from 6-nitro-4-methyl coumarinyl chloroacetate (5) and 2-amino thiazines (IIIa–j). The structure of the final compounds was adequately confirmed via spectroscopic techniques (IR, 1H NMR, 13C NMR, Mass) and characterization of physical properties. Final compounds were screened for their antimicrobial, antitubercular, and antioxidant activities. Compounds 5c and 5h found to have antibacterial potency against E. coli with MIC values 50 μg/mL compared to standard drugs. Compound 5d demonstrated better antifungal potency (MIC = 200 μg/mL) against C. albicans when compared with griseofulvin. Compounds 5b and 5h found to be encouraging antitubercular (MIC = 62.5 μg/mL with 98–99% inhibition) against M. tuberculosis H37Rv. The newly synthesized 5h and 5b were appeared to have high radical scavenging efficacies as 33.99 ± 0.301 and 35.35 ± 0.470 μg/mL ± SD of IC50 values, respectively, in DPPH and ABTS bioassay.
- Chauhan, Nilesh B.,Patel, Navin B.,Patel, Vatsal M.,Mistry, Bhupendra M.
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p. 2141 - 2149
(2018/07/21)
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- Synthesis of Fused Oxazolocoumarins from o-Hydroxynitrocoumarins and Benzyl Alcohol Under Gold Nanoparticles or FeCl3 Catalysis
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Synthesis of fused oxazolocoumarins has been achieved from the one-pot tandem reactions of o-hydroxynitrocoumarins with benzyl alcohol in toluene under catalysis in a sealed tube at 150°C. The catalysis was performed by gold nanoparticles supported on TiO
- Vlachou, Evangelia-Eirini N.,Armatas, Gerasimos S.,Litinas, Konstantinos E.
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p. 2447 - 2453
(2017/07/25)
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- Preparative-scale synthesis of amino coumarins through new sequential nitration and reduction protocol
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In contrast to the conventional deleterious approach for nitration (for example HNO3/H2SO4) and for reduction (for example Zn/HCl), we hypothesized that sensitive heterocycles such as coumarins could not withstand with those hard conditions. Hence, while studying this reaction sequence to prepare amino coumarins (which is our ongoing project to synthesize antitubercular coumarin agents), we came across mild and greener reagent for nitration using calcium nitrate (Ca(NO3)2·4H2O; lime nitrate), and reduction using D-glucose. These two mild, chemoselective, high yielding methods are discussed herein.
- Chaudhari, Hemchandra K.,Pahelkar, Akshata,Takale, Balaram S.
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supporting information
p. 4107 - 4110
(2017/09/28)
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- Regioselective mononitration of coumarins using claycop reagent
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Coumarins are nitrated by claycop (cupric nitrate impregnated on the K10 montmorillonite) in acetic anhydride at room temperature to give corresponding regioselective mononitro coumarins in good to excellent yields. Among the products three nitrocoumarins are new.
- Kanodia, Saraswati,Thapliyal, Prakash Chander
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experimental part
p. 241 - 244
(2012/03/11)
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- Solid-state regioselective nitration of activated hydroxyaromatics and hydroxycoumarins with cerium (IV) ammonium nitrate
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Predominant ortho-selective mononitration of low-melting and liquid phenols and hydroxycoumarins in moderate to high yields has been accomplished upon grinding with solid cerium (IV) ammonium nitrate (CAN). Microwave-assisted expeditious CAN-mediated nitration of relatively high melting phenols and hydroxycoumarins with high efficiency and selectively under solvent-free conditions has been also developed to address the problems of sluggishness and low yield for these reluctant substrates.
- Ganguly, Nemai C.,Dutta, Sanjoy,Datta, Mrityunjoy,De, Prithwiraj
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p. 733 - 735
(2007/10/03)
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- Novel method for synthesis of some biologically active aminocoumarins
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Nitration of coumarin 4-methyl acetates using concentrated HNO3 in solvents like chloroform or dichloromethane at lower temperature 'Cheparon effect' was found to occur only on aromatic part of coumarin. Yields of nitrocoumarins are almost quantitative and isomers were separated using column chromatographic technique. Reduction of the nitrocoumarins was carried out in environmentally friendly hydride transfer system using Pd/C as catalyst and formic acid or phosphorous acid as hydride generating reagent. Functional groups like -OH, Br, COCH3, -CH2COOH3 and lactone were not interfering in the reduction of nitro group to amino.
- Mashelkar,Audi
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p. 258 - 261
(2008/09/21)
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- Guanidinium nitrate: A novel reagent for aryl nitrations
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Nitration of various aromatic compounds utilising guanidinium nitrate in 85% sulfuric acid as a nitrating agent has been studied.
- Ramana,Malik,Parihar
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p. 8681 - 8683
(2007/10/03)
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- Cerium(IV) ammonium nitrate mediated nitration of coumarins
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A new convenient method of nitration of coumarins using cerium(IV) ammonium nitrate (CAN) has been developed. Higher regioselectivity is observed with CAN and hydrogen peroxide in aqueous medium in comparison with CAN in acetic acid for nitration of 7-hydroxycoumarin, 7-hydroxy-4-methylcoumarin and their derivatives.
- Ganguly,Sukai,De
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p. 301 - 309
(2007/10/03)
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