- Synthesis, characterization, in vitro antimicrobial and anticancer evaluation of random copolyesters bearing biscoumarin units in the main chains
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A series of aliphatic-aromatic random copolyesters bearing a biscoumarin group were synthesized by phase-transfer-catalyzed interfacial polycondensation of 3,3′-methylene-bis(4-hydroxycoumarin)1 and aromatic diols such as hydroquinone, resorcinol, ethyl resorcinol, bisphenol-A, and curcumin with sebacoyl chloride. These copolyesters were obtained with yields in the range between 76 and 85 % and the inherent viscosity between 0.22 and 0.33 dl/g. All the copolyesters were found to be soluble in chlorinated and polar aprotic solvents. The chemical structures of the copolyesters were analyzed by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance (1H-NMR) spectroscopy. The physical properties of copolyesters obtained by altering the aromatic diols 3, were characterized by thermogravimetric analysis, differential scanning calorimetry, gel permeation chromatography, and X-ray diffraction (XRD) technique. Copolyesters exhibited good thermal stability having a decomposition temperature above 223 °C. Copolyesters with the bisphenol group as backbone exhibited higher thermal stability than others. Results revealed that the copolyesters exhibit a glass transition temperature in the range of -11 to 54 °C. It was found that copolyester with ethyl resorcinol and curcumin shown low and high T g values, respectively. XRD measurement revealed the amorphous nature of copolyester with a low degree of crystallinity. Agar disc diffusion method was employed to study the antimicrobial activity of these random copolyesters. The synthesized copolyester was subjected to in vitro anticancer activity against lung cancer (Hep-2) cell line.
- Kandaswamy, Narendran,Raveendiran, Nanthini
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- Et2AlCl promoted coupling reactions of 4-hydroxy-2-pyrone or 4- hydroxycoumarine with aldehydes: Synthesis of methylenebis(4-hydroxy-2- pyrone) or methylenebis(4-hydroxycoumarine) derivatives
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Methylenebis(4-hydroxy-2-pyrone) or methylenebis(4-hydroxy-coumarine) derivatives (5) have been synthesized from 4-hydroxy-2-pyrones (6) and (8) or 4-hydroxycoumarine (10) with aldehydes (4) in the presence of diethylaluminum chloride.
- Hagiwara, Hisahiro,Miya, Shigeki,Suzuki, Toshio,Ando, Masayoshi,Yamamoto, Isao,Kato, Michiharu
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- Electrochemically induced cross-dehydrogenative coupling (CDC) reaction. An efficient electrochemical method for the synthesis of dicoumarols
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Electrochemical synthesis of dicoumarols as anticoagulant drugs was carried out by the electrochemical oxidation of N,N,N′,N′-tetramethyl-1,4-phenylenediamine in the presence of 4-hydroxycoumarin derivatives. Electrochemically generated radical cation par
- Dadpou, Bita,Nematollahi, Davood
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- Fluorescence solvatochromism and modulated anticholinergic activity of novel coumarin compounds sequestered in human serum albumin nanocavities
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A coumarin compound, 3,3′-methylenebis(4-hydroxy-2H-chromen-2-one) (MHC), and its substituted derivative, 3,3′-(phenylmethylene)bis(4-hydroxy-2H-chromen-2-one) (MHCB), possess potent anticholinergic activities, which were found to be reduced significantly in the presence of human serum albumin (HSA). The molecular interactions responsible for sequestering MHC and MHCB were explored by steady-state and time-resolved fluorescence using the modulated solvatochromic behavior of the probes as a fluorescent marker. A quantitative description of the different solvent parameters responsible for the notable solvent-dependent photo-physical properties of the investigated systems was extracted from multiple linear regression analysis of the experimental data using the Kamlet-Taft and Catalán formalisms. A series of complimentary studies involving circular dichroism measurement and molecular docking calculations revealed that the binding of both coumarin derivatives resulted in the stabilization of the α-helical structure of human serum albumin (HSA). However, significant differences in binding mechanism were noted in terms of the strength, mode and principal forces responsible for the spontaneous association of the probes into the protein-binding domain.
- Rohman, Mostofa Ataur,Baruah, Prayasee,Bhattacharjee, Deboshika,Myrboh,Mitra, Sivaprasad
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- New biscoumarin and dihydropyran derivatives as antimicrobials
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In an attempt to find a new class of antimicrobial agents, a series of biscoumarin (1-4) and dihydropyran (5 and 6) derivatives were prepared. These compounds were screened for their in vitro antibacterial activity against Staphylococcus aureus (S. aureus ATCC 29213), methicillin-resistant S. aureus (MRSA XJ 75302), vancomycin-intermediate S. aureus (Mu50 ATCC 700699), and USA 300 (Los Angeles County clone, LAC). There are two classical intramolecular O-H···O hydrogen bonds (HBs) in the structures of biscoumarins 1-4 and the corresponding total HB energy were further performed with the density functional theory (DFT) [B3LYP/6-31G] method.
- Li, Jing,Meng, Jing-Ru,Qu, Di,Zhang, Zi-Dan,Li, Fen,Yang, Xiao-Hui,Luo, Xiao-Xing,Li, Jiang-Tao,Li, Ming-Kai
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- Coumarin compound as well as preparation method and application thereof
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The invention provides a coumarin compound as well as a preparation method and application thereof, and mainly aims to prepare a medicine for treating cognitive impairment caused by high-fat diet and meeting partial or all standards, and weight gain caused by high-fat diet can be remarkably inhibited under the condition of not influencing physiological growth and metabolism. The compound acts on a wide range of target organs (such as intestines, livers and brains) and can remarkably relieve systemic oxidative stress induced by high-fat diet; intestinal tract and liver injuries induced by high-fat diet are blocked, lipid and glucose metabolism disorders are relieved, and insulin resistance is relieved; the brain metabolism is improved, the oxidative stress of brain tissues is relieved, and the cognitive function is improved. The compound has light toxic and side effects as a medicine, and is practicable for treating cognitive impairment caused by high-fat diet.
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Paragraph 0038-0047
(2021/04/14)
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- Redox-Triggered Switchable Synthesis of 3,4-Dihydroquinolin-2(1 H)-one Derivatives via Hydride Transfer/ N-Dealkylation/ N-Acylation
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The switchable synthesis of 3-non, 3-mono, 3,3′-disubstituted 3,4-dihydroquinolin-2(1H)-ones was developed through a redox-neutral hydride-transfer/N-dealkylation/N-acylation strategy from o-aminobenzaldehyde with 4-hydroxycoumarin, and Meldrum's acid, respectively. The unprecedented strategy for the synthesis of 3,3′-highly functionalized 3,4-dihydroquinolin-2(1H)-one has been realized with the in situ utilization of the released HCHO via the o-QM involved Michael addition. In addition, the synthetic utility of this protocol has been well illustrated via concise synthesis of CYP11B2 inhibitor.
- Hu, Fangzhi,Li, Sanming,Li, Shuai-Shuai,Wang, Liang,Xu, Lubin,Yang, Xiaoyu
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supporting information
p. 358 - 364
(2021/01/13)
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- The magnetic nanostructured natural hydroxyapatite (HAP/Fe3O4 NPs): an efficient, green and recyclable nanocatalyst for the synthesis of biscoumarin derivatives under solvent-free conditions
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Abstract: The magnetic nanostructured natural hydroxyapatite (HAP/Fe3O4 NPs) as a novel magnetic nanocatalyst was synthesized and fully characterized. The excellent catalytic activity of HAP/Fe3O4 NPs was investigated in the synthesis of biscoumarin derivatives under mild, green and solvent-free conditions. A series of aromatic (bearing different functional groups), heteroaromatic and aliphatic aldehydes have been converted to biscoumarins with good to excellent isolated yields. The significant advantages offered by the present method in close agreement with green chemistry principles are: catalyst is inexpensive, non-toxic, easy handling and reusable up to six recycle runs, magnetic separation of nanostructured catalyst, simple work-up procedure, short reaction time, high yields of products and using solvent-free conditions. Graphical abstract: [Figure not available: see fulltext.].
- Akhlaghinia, Batool,Sanati, Parvin,Mohammadinezhad, Arezou,Zarei, Zeinab
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- A catalyst-free 1,4-Michael-type reaction of in situ generated ortho-quinone methides (o-QMs) with dithiocarbamic acid salts in water
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Abstract: A catalyst-free conjugate addition of dithiocarbamic acid salts to in situ generated ortho-quinone methides (o-QMs) was investigated for the first time. Several dithiocarbamate derivatives of 4-hydroxycoumarine, 4-hydroxypyrone and 2-naphthol were synthesized in moderate-to-good yields in water at room temperature. Graphical abstract: [Figure not available: see fulltext.] Catalyst-free addition of dithiocarbamic acid salts to in situ generated o-QMs in water at room temperature.
- Aryanasab, Fezzeh,Shabanian, Meisam
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p. 1703 - 1713
(2019/04/17)
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- Starch-sulfuric acid as a bio-supported and recyclable solid acid catalyst for rapid synthesis of α,α′-benzylidene bis(4-hydroxycoumarin) derivatives
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Starch-sulfuric acid-catalyzed, simple, one pot, solvent-free, environmentally benign synthesis of α,α′-benzylidene bis(4-hydroxycoumarin) derivatives has been achieved by reaction of aromatic aldehydes with 4-hydroxycoumarin. The catalyst is reusable and has remarkable activity. This procedure has several advantages including high yields, short reaction times, easy work-up, and use of an inexpensive, moderately acidic, safe catalyst.
- Rezaei, Ramin,Sheikhi, Mohammad Reza
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p. 1283 - 1292
(2015/03/04)
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- Ca(II)-catalyzed, one-pot four component synthesis of functionally embellished benzylpyrazolyl coumarins in water
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A facile one-pot, four-component synthesis of biologically important benzylpyrazolyl coumarins in water has been demonstrated using environmentally benign Ca(II) as the catalyst. Participation of aliphatic aldehydes has been described for the first time. Short reaction times, high yields and chromatography free isolation of the products, usage of eco-friendly catalyst and solvent are the key features of this method.
- Yaragorla, Srinivasarao,Pareek, Abhishek,Dada, Ravikrishna
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supporting information
p. 4770 - 4774
(2015/07/20)
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- Synthesis of 3-aminomethyl-4-hydroxycoumarins and their retro-Mannich reaction in dimethyl sulfoxide
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Hydrogenation of 3-formyl-4-hydroxycoumarin aliphatic imines leads to 3-aminomethyl-4-hydroxycoumarins, which undergo a retro-Mannich reaction in dimethyl sulfoxide containing even traces of water.
- Milevskii,Chibisova,Solovéva,Sukhorukov, A. Yu.,Traven
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p. 423 - 428
(2015/10/29)
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- Design and synthesis of 3,3′-biscoumarin-based c-Met inhibitors
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A library of biscoumarin-based c-Met inhibitors was synthesized, based on optimization of 3,3′-biscoumarin hit 3, which was identified as a non-ATP competitive inhibitor of c-Met from a diverse library of coumarin derivatives. Among these compounds, 38 and 40 not only showed potent enzyme activities with IC50 values of 107 nM and 30 nM, respectively, but also inhibited c-Met phosphorylation in BaF3/TPR-Met and EBC-1 cells. This journal is the Partner Organisations 2014.
- Xu, Jimin,Ai, Jing,Liu, Sheng,Peng, Xia,Yu, Linqian,Geng, Meiyu,Nan, Fajun
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p. 3721 - 3734
(2014/06/09)
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- Propane-1,2,3-triyl tris(hydrogen sulfate): A mild and efficient recyclable catalyst for the synthesis of biscoumarin derivatives in water and solvent-free conditions
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A simple, efficient, and ecofriendly procedure has been developed using propane-1,2,3-triyl tris(hydrogen sulfate) as a catalyst for the synthesis of biscoumarin derivatives in water and solvent-free conditions. The significant features of the present protocol are simplicity, environmentally benign, high yields, no chromatographic separation, and recyclability of the catalyst.
- Rezaei, Ramin,Moezzi, Fatemeh,Doroodmand, Mohammad Mahdi
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p. 183 - 186
(2014/02/14)
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- Synthesis, antibacterial activities, and theoretical studies of dicoumarols
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Four dicoumarols (DC, 2-PyDC, 3-PyDC and 4-PyDC) were synthesized and characterized via IR, 1H NMR, HRMS, and single crystal X-ray crystallography. Two classical intramolecular O-H...O hydrogen bonds (HBs) stabilized their structures. The total HB energies in DC, 2-PyDC, 3-PyDC and 4-PyDC were calculated with the density functional theory (DFT) [B3LYP/6-31G*] method. The in vitro antibacterial activity of DC, 2-PyDC, 3-PyDC and 4-PyDC against Staphylococcus aureus (S. aureus ATCC 29213), methicillin-resistant S. aureus (MRSA XJ 75302), vancomycin-intermediate S. aureus (Mu50 ATCC 700699), and USA 300 (Los Angeles County clone, LAC) was evaluated by observing the minimum inhibitory concentration and time-kill curves. The results showed that among all the compounds, 2-PyDC exhibited the most potent antibacterial activity. This journal is the Partner Organisations 2014.
- Li, Jing,Hou, Zheng,Chen, Guang-Hui,Li, Fen,Zhou, Ying,Xue, Xiao-Yan,Li, Zhou-Peng,Jia, Min,Zhang, Zi-Dan,Li, Ming-Kai,Luo, Xiao-Xing
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p. 5528 - 5535
(2014/07/21)
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- Synthesis of a new series of 2-(2-oxo-2H-chromen-3-yl)-5H-chromeno[4,3-b] pyridin-5-ones by two facile methods and evaluation of their antimicrobial activity
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A series of novel 2-(2-oxo-2H-chromen-3-yl)-5H-chromeno[4,3-b]pyridin-5- ones 4a-4l have been synthesized using two methodologies (using Mannich base of 4-hydroxy coumarin and 4-chloro-3-formyl coumarin) (Patel et al., 2012) and assayed for their antibacterial activity against gram-positive bacteria viz. Bacillus subtilis (MTCC 441), Staphylococcus aureus (MTCC 96) and gram-negative bacteria viz. Escherichia coli (MTCC 443), Salmonella typhimurium (MTCC 98). The compounds 4a-4l were also assayed for their antifungal activity against Aspergillus niger (MTCC 282) and Candida albicans (MTCC 227). All the compounds 4a-4l exhibited potent inhibitory activity against gram-positive bacteria compared to standard drugs at the tested concentrations. The compounds also showed appreciable activity against gram-negative bacteria as well as fungi. The compounds 4e, 4f, 4i, 4k, and 4l are found to be the most proficient members of the series and emerged as potential molecules for further development. Graphical Abstract: [Figure not available: see fulltext.]
- Patel, Apoorva A.,Lad, Hemali B.,Pandya, Kinnar R.,Patel, Chirag V.,Brahmbhatt, Dinkar I.
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p. 4745 - 4754
(2013/09/23)
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- Sulfated titania catalyzed water mediated efficient synthesis of dicoumarols - A green approach
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An efficient, mild, and environmental friendly method has been developed for the synthesis of dicoumarols in water over Lewis and Bronsted acid catalyst sulfated titania (TiO2/SO42-). The method involves the condensation of various aromatic and aliphatic aldehydes with 4-hydroxycoumarin. It affords the corresponding product in high yield with short reaction times employing a very low loading of catalyst. The catalyst was reused several times without significant change in activity.
- Karmakar, Bikash,Nayak, Anupam,Banerji, Julie
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experimental part
p. 4343 - 4346
(2012/09/22)
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- Catalyst-free hydroarylation of in situ generated ortho-quinone methide (o-QM) with electron rich arenes in water
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We report the first C-H hydroarylation of in situ generated ortho-quinone methides with electron-rich arenes. The reaction takes place in water without any catalyst, and is highly regioselective. Ionic and non-ionic additives provide an increase in reaction rate, yield, and regioselectivity.
- Kumar, Atul,Kumar, Mukesh,Gupta, Maneesh Kumar
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p. 2677 - 2681,5
(2020/09/14)
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- Reaction of dimethyl sulfoxide with 4-acyloxycoumarins
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Dimethyl sulfoxide converts 4-acetoxycoumarin (1) exclusively to 2-(2-hydroxybenzoyl)-2-[(methylthio)methyl]-2,3-dihydro-4H-furo[3,2-c] chromen-4-one (3) at 180°C under a nitrogen atmosphere, but in the absence of nitrogen, the products obtained are dicou
- Ara, Tabassum,Khan, Khaliquz Zaman,Tasneem, Khalida
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experimental part
p. 4416 - 4422
(2010/05/17)
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- Synthesis, characterization, in-vitro biocidal and nuclease activity of Cu(II), Fe(II) and Fe(III) complexes
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Complexes of Cu(II), Fe(II), and Fe(III) have been synthesized by reaction of their metal salts with bis(4-hydroxy-2oxo-2H-chromen-3-yl)-methane or bis(4-hydroxy-2oxo-2H-chromen-3-yl)-thiophene-2yl-methane or bis(4-hydroxy-2oxo-2H-chromen-3-yl)-pyridin-3yl-methane in molar ratio 1:2. They have been characterized using 1H-NMR, 13C-NMR, IR spectra, electronic spectra, magnetic measurements and elemental analyses and screened for their in-vitro antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Salmonella typhi, and Serratia marcescens. The metal complexes exhibit moderate antimicrobial activity compared to parental compounds and standard drugs. In-vitro nuclease activity has been determined using agarose gel electrophoresis. The synthesized compounds show effective nuclease activity.
- Pansuriya,Chhasatia,Patel,Patel
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p. 1527 - 1539
(2008/12/23)
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- Biscoumarin: New class of urease inhibitors; Economical synthesis and activity
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A variety of biscoumarins (1-21) with variable substituents at C-11 were synthesized with an improved method and evaluated as urease inhibitors. The synthesized compounds showed varying degree of urease inhibitory activity ranging from 15.06-91.35 μM. The size and electron donating or withdrawing effects of substituents influenced the activity, which lead to the urease inhibitors.
- Khan, Khalid Mohammed,Iqbal, Sajid,Lodhi, Muhammad Arif,Maharvi, Ghulam Murtaza,Zia-Ullah,Choudhary, Muhammad Iqbal,Atta-ur-Rahman,Perveen, Shahnaz
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p. 1963 - 1968
(2007/10/03)
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- Synthesis of methylenebis(4-hydroxy-2-pyrone) or methylenebis(4- hydroxycoumarin) derivatives by organic solid state reaction
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Methylenebis(4-hydroxy-2-pyrone) or methylenebis(4-hydroxycoumarin) derivatives (5) have been synthesized from 4-hydroxy-2-pyrones or 4- hydroxycoumarin (3) with aldehydes (4) by organic solid state reaction.
- Hagiwara, Hisahiro,Fujimoto, Norikazu,Suzuki, Toshio,Ando, Masayoshi
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p. 549 - 552
(2007/10/03)
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- Coumarin-based inhibitors of HIV integrase
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The structures of a large number of HIV-1 integrase inhibitors have in common two aryl units separated by a central linker. Frequently at least one of these aryl moieties must contain 1,2-dihydroxy substituents in order to exhibit high inhibitory potency. The ability of o-dihydroxy-containing species to undergo in situ oxidation to reactive quinones presents a potential limitation to the utility of such compounds. The recent report of tetrameric 4-hydroxycoumarin-derived inhibitor 5 provided a lead example of an inhibitor which does not contain the catechol moiety. Compound 5 represents a large, highly complex yet symmetrical molecule. It was the purpose of the present study to determine the critical components of 5 and if possible to simplify its structure while maintaining potency. In the present study, dissection of tetrameric 5 (IC50 = 1.5 μM) into its constituent parts showed that the minimum active pharmacophore consisted of a coumarin dimer containing an aryl substituent on the central linker methylene. However, in the simplest case in which the central linker aryl unit consisted of a phenyl ring (compound 8, IC50 = 43 μM), a significant reduction in potency resulted by removing two of the original four coumarin units. Replacement of this central phenyl ring by more extended aromatic systems having higher lipophilicity improved potency, as did the addition of 7- hydroxy substituents to the coumarin rings. Combining these latter two modifications resulted in compounds such as 3,3'-(2- naphthalenomethylene)bis[4,7-dihydroxycoumarin] (34, IC50 = 4.2 μM) which exhibited nearly the full potency of the parent tetramer 5 yet were structurally much simpler.
- Zhao, He,Neamati, Nouri,Hong, Huixiao,Mazumder, Abhijit,Wang, Shaomeng,Sunder, Sanjay,Milne, George W. A.,Pommier, Yves,Burke Jr., Terrence R.
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p. 242 - 249
(2007/10/03)
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- The Chemistry of Coumarin Derivatives Synthesis of 3-Alkyl-4-hydroxycoumarins by Reductive Fragmentation of 3,3'-Alkylidene-4,4'-dihydroxybis
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Treatment of 3,3'-alkylidene-4,4'-dihydroxybis 1 with NaBH3CN in refluxing MeOH affords 3-alkyl-4-hydroxycoumarins 2 and 4-hydroxycoumarin (3; Scheme 1).The reaction may take place via hydride trapping of alkylidenechromandiones C formed from 1 in a retro-Michael reaction.Such a retro-Michael reaction of 1 might be biologically relevant.The presence of C during the reductive fragmentation 1 --> 2 is suggested by Diels-Alder and nucleophilic trapping of the alkylidenechromandiones C as well as from cross-over experiments with coumarins other than 3 (see Scheme 2).The reductive fragmentation of 1 allows the chemo- and regioselective synthesis of a variety of 3-alkyl-4-hydroxycoumarins 2 (see Table).
- Appendino, Giovanni,Cravotto, Giancarlo,Tagliapietra, Silvia,Ferraro, Stefano,Nano, Gian Mario,Palmisano, Giovanni
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p. 1451 - 1458
(2007/10/02)
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- Reaction of Dimethyl Sulphoxide and Acetic Anhydride with 3-Substituted 4-Hydroxycoumarins
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The DMSO-Ac2O reagent reacts with 4-hydroxy-3-phenylcoumarin to give 3-(2-hydroxyphenyl)-2-phenyl-1-thiomethylpropan-3-one (1a) and 6H,11H-benzopyranobenzopyran-11-one (3).A similar reaction of 3-allyl-4-hydroxycoumarin gives 2-allyl-3-(2-hydroxyphenyl)-1-thiomethylpropan-3-one (1b).However, the same reagent, when modified by prior heating, reacts with 6H,7H-7-(4-hydroxy-3-coumaranyl)benzopyranobenzopyran-6-one (7a) to give dicoumarol, 7-thiomethyl-6H,7H-benzopyranobenzopyran-6-one (8) and 4-hydroxy-3-methylthiomethoxy-2H-benzopyran-2-one (10).
- Khan, Khaliquz Zaman,Tasneem, Khalida,Rahman, Mujeebur,Prakash, Satya,Zaman, Asif
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- The Reaction of Dimethyl Sulphoxide and Acetic Anhydride with 4-Hydroxycoumarin and Dicoumarol
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Dimethyl sulphoxide and acetic anhydride convert 4-hydroxycoumarin (1a) into the acetate but at 120 deg C this is further transformed into the ylide 3-dimethylsulphoniochroman-2,4-dionate (2).At 160 deg C the reaction affords dicoumarol (3a) and other products derived from this by further reactions.These products are 2,3-dihydro-2-(2-hydroxybenzoyl)-4H-furobenzopyran-4-one (6a), 2-(2-hydroxybenzoyl)-4H-furobenzopyran-4-one (11a), 3-(2,3-dihydro-2-hydroxymethyl-3-oxobenzofuran-2-ylmethyl)-4-hydroxycoumarin (13), and 2,3-dihydro-2-(2-hydroxybenzoyl)-2-hydroxymethyl-4H-furobenzopyran-4-one (12a).Compound (6a) is readily dehydrogenated to give compound (11a), which is identical with a known compound obtained by treating dicoumarol with iodine in ethanol.Pyrolysis of compound (12a) affords (6a); pyrolysis of compound (13) affords the spiran (14).Spectroscopic studies did not establish the structure of compound (6a) unequivocally and the compound failed to give the appropriate positive responses to iron(III) salts and Gibbs' dichlorobenzoquinonechloroimine reagent because the dihydrofuran system reduced these reagents, the furan (11a) behaving normally.Chemical evidence for structure (6a) depends mainly upon the ability of boron trichloride to regenerate this compound from its methyl ether.
- Khan, Khaliquz-Zaman,Minhaj, Najme,Tasneen, Khalida,Zaman, Asif,Shiengthong, Dep,et al.
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p. 841 - 850
(2007/10/02)
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- SYNTHESIS AND STUDY OF THE PROPERTIES OF 4-SUBSTITUTED 3-AMINOMETHYLCOUMARINS
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The aminomethylation of 4-hydroxycoumarin gave 3-pyrrolidinomethyl- and 3-piperidinomethyl-4-hydroxycoumarins, which were converted to 4-chloro derivatives by the action of phosphorus oxychloride.A number of 3-pyrrolidinomethyl- and 3-piperidinomethyl-4-aminocoumarins were synthesized by reaction of the 4-chloro derivatives with various amines, and some of their properties were studied.
- Savel'ev, V. L.,Artamonova, O. S.,Troitskaya, V. S.,Shaviryna, V. V.,Afanas'eva, T. G.,Zagorevskii, V. A.
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p. 676 - 679
(2007/10/02)
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- A General and Practicable Synthesis of Polycyclic Heteroaromatic Compounds. Part 4. A Rationale for the Mechanism of the Synthesis
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Studies on aspects of the mechanism of our general synthesis of polycyclic heteroaromatic compounds suggest that the reaction sequence outlined in Scheme 2 is followed.Under the conditions of our synthesis, the ortho-rearrangement (8) --> (9) is preferred to the para-rearrangement which is known to occur in acid conditions.Aniline Mannich bases (29) are converted to benzacridines (30) in an intermolecular reaction.The synthesis appears to be restricted to substrates where the putative intermediate (9) is not part of an amide group.In the course of these studies effective syntheses of the tricyclic compounds (24) and (25) have been discovered.
- Asherson, Janet L.,Bilgic, Orhan,Young, Douglas W.
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p. 3041 - 3047
(2007/10/02)
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- ANODIC OXIDATION OF PYRONES AND RELATED COMPOUNDS
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Triacetic lactone, 4-hydroxycoumarins, and kojic acid derivative were subjected to anodic oxidation in MeOH containing LiClO4 or NaCN to afford the corresponding methoxy or cyano compounds.In a basic media, however, dipyrone and dicoumarol were produced from triacetic lactone and 4-hydroxycoumarin, respectively.The formation process of 3-methoxytriacetic lactone as well as of 3-cyanotriacetic lactone is also presented.
- Iguchi, Masanobu,Nishiyama, Atsuko,Eto, Hideo,Yamamura, Shosuke
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p. 1323 - 1326
(2007/10/02)
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