- An efficient synthesis of flavanones and their docking studies with aldose reductase
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A series of flavanone derivatives have been synthesized from 2-hydroxy acetophenone and benzaldehyde using fused calcium chloride in good to moderate yields, and their in vitro aldose reductase inhibitory activity has been tested on aldose reductase purified enzyme from Bovine lens. Most of the synthesized compounds exhibited potent aldose reductase inhibitory activity, and the obtained results are supported by the docking studies. Among the tested derivatives, 2, 3, 4-methoxy derivative 19 (IC50 5.88 ± 0.03 μM) exhibited the highest inhibitory activity whereas 2-methoxy derivative 12 showed the lowest, and the remaining compounds exhibited moderate activity with IC50 in the range of 6.09–7.89 μM. The spatial configuration of the most active derivative 19 was compared with pharmacophore requirements of the aldose reductase inhibitor site using a molecular modeling system.
- Kondhare,Gyananath,Tamboli, Yasinalli,Kumbhar, Santosh S.,Choudhari, Prafulla B.,Bhatia, Manish S.,Zubaidha
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p. 987 - 998
(2017/04/14)
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- Guanidino-graphene catalysed synthesis of flavones via Aldol-Michael-oxidation
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Guanidino-graphene has been synthesized by the reaction of bromoamine with reduced graphene oxide and characterized by FT-IR, Raman, TGA, powder XRD, TEM, SEM, and zeta potential. It is a cheap, heterogeneous and environmentally benign solid base catalyst used for cascade Aldol-Michael-oxidation in the synthesis of chalcone, flavonoids.
- Mishra, Sweta,Arora, Smriti,Nagpal, Ritika,Chauhan, Shive Murat Singh
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p. 2525 - 2530
(2017/03/09)
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- Applications of caged-designed proton sponges in base-catalyzed transformations Dedicated to Professor Milan Kratochvíl for his 90th birthday anniversary.
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Superbasic properties of caged proton sponges (PSs) - substituted diazatetracyclo[4.4.0.13,10.15,8]dodecanes (DTDs) - were utilized in Knoevenagel and Claisen-Schmidt condensations, the Pudovik reaction, and Michael addition. This investigation covers the influence of the solvent, reaction temperature, catalyst loadings as well as the electronic properties of substituents upon the reaction. Moreover, we provided an activity comparison between our new base and a well-known and commercially available proton sponge (DMAN). The basicity (in MeCN) of our chosen DTD (pKBH+=21.7±0.1) exceeded the prototypal PS - 1,8-bis(dimethylamino)naphthalene (DMAN, pKBH+=18.6), by three orders of magnitude. We proved that DTDs are reasonably active species in monitored reactions, which is a consequence of a hydrogen bridge angle (~130°) between the two nitrogen atoms and the captured proton. We present here syntheses of aminoindolizine, substituted 4H-chromene, and flavanones, and the unexpected formation of a bis-addition product formed after Michael addition, all under mild conditions.
- Galeta, Juraj,Potá?ek, Milan
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- Fe(HSO4)3/SiO2: An efficient and heterogeneous catalyst for one-pot synthesis of 2-aryl-chromene-4-ones (flavanones)
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Silica ferric hydrogensulphate is an efficient heterogeneous catalyst for cyclisation of 2-hydroxychalcones to their corresponding flavanones (chromanone). This intramolecular oxa-Michael reaction was carried out in high yields in the presence of electron donating and electron withdrawing groups in the chalcone structure. Also, we found that aniline can act as an organic co-catalyst in direct synthesis of flavanones from 2-hydroxyacethophenone and aldehydes in the presence of Fe(HSO4)3/SiO2. Flavanones were prepared in high yields in a new catalytic system with similar substituted effect in the indirect cyclisation method. The catalyst in all the above reactions is reusable without significant decreases in its activity after four times of recycling.
- Eshghi, Hossein,Rahimizadeh, Mohammad,Mousavi, Seyed Mohsen
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supporting information
p. 438 - 443
(2014/04/17)
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- SAR studies of o-hydroxychalcones and their cyclized analogs and study them as novel inhibitors of cathepsin B and cathepsin H
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Cathepsins have emerged as a potential target for anti-cancer drug development. In the present study, we have synthesized three structurally related series of flavanoids i.e., 2′-hydroxychalcones, flavanones and flavones and assayed in vitro to study their inhibitory potency against cathepsin B and H, promising drug candidate for cancer therapy. Enzyme kinetics studies were carried out in presence of these compounds after preliminary proteolytic studies on endogenous protein substrates. SAR studies suggested that open chain flavanoids were better inhibitors as compared to their cyclized analogs. The most potent inhibitors among the three series were nitro substituted compounds 1g, 2g and 3g with Ki values of ~6.18 × 10-8 M, 4.8 × 10-7 M and 7.85 × 10-7 M for cathepsin B and Ki values of ~2.8 × 10-7 M, 31.8 × 10-6 M and 33.7 × 10 -6 M for cathepsin H, respectively. The relationship between chalcone, flavanones and flavone structures interpreted by docking studies on cathepsin B and H also provided useful insights.
- Raghav,Garg
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- Hydromagnesite as an efficient recyclable heterogeneous solid base catalyst for the synthesis of flavanones, flavonols and 1,4-dihydropyridines in water
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A form of hydromagnesite (HM) with flower-like thin-sheet morphology was synthesized by an environmentally benign approach using simple conventional heating at moderate temperature without using any template in water as medium. The versatility of this HM catalyst was studied in the synthesis of flavanones, flavonols and the multicomponent synthesis of 1,4-dihydropyridines in water. The recyclability of catalyst was studied for six times and there was no appreciable loss in its catalytic activity. Copyright
- Rajesh, U. Chinna,Manohar, Sunny,Rawat, Diwan S.
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p. 3170 - 3178
(2013/12/04)
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- Iodine catalyzed one-pot synthesis of flavanone and tetrahydropyrimidine derivatives via Mannich type reaction
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A variety of functionalized flavanone derivatives and tetrahydropyrimidine derivatives were achieved under remarkably mild conditions. The combination of good to excellent yields, a simple work-up, and the high compatibility of functional groups makes this an attractive synthetic approach to access flavanone and tetrahydropyrimidine derivatives.
- Kavala, Veerababurao,Lin, Chunchi,Kuo, Chun-Wei,Fang, Hulin,Yao, Ching-Fa
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experimental part
p. 1321 - 1329
(2012/02/13)
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- Synthetic approach to flavanones and flavones via ligand-free palladium(ii)-catalyzed conjugate addition of arylboronic acids to chromones
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The remarkable catalytic effects of Fe(OTf)3 in the context of the Pd(ii)-catalyzed conjugate addition of arylboronic acids to chromones were observed to yield a variety of flavanones under mild conditions. The addition of catalytic amounts of DDQ and KNO2 to the reactions exclusively yielded flavone analogs. The reaction scope for the transformation was fairly broad, affording good yields of a wide range of flavanones and flavones, which are privileged structures in many biologically active compounds.
- Kim, Donghee,Ham, Kyungrok,Hong, Sungwoo
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experimental part
p. 7305 - 7312
(2012/09/22)
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- Synthesis of flavanones, azaflavanones, and thioflavanones catalyzed by PMA-SiO2 as a mild, efficient, and reusable catalyst
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Cyclization of a variety of chalcones to flavanones catalyzed by 1 mol% phosphomolybdic acid (PMA) supported on silica as a mild, efficient, and reusable catalyst was carried out in high yields. PMA-SiO2 is an efficient, inexpensive, and green catalyst which gave high conversion yields and could be recycled up to three times without significant loss in activity. Springer-Verlag 2011.
- Sakirolla, Raghavendra,Yaeghoobi, Marzieh,Rahman, Noorsaadah Abd.
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experimental part
p. 797 - 800
(2012/09/07)
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- Environmentally benign syntheses of flavanones
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Mild and environmentally benign methods for the syntheses of flavanones are described. The reaction of o-hydroxyacetophenones (1) and benzaldehydes (2) in water in the presence of DABCO at room temperature gave 3-hydroxy-1-(2- hydroxylphenyl)-3-arylpropan-1-ones (3a-i) as intermediates. Followed by an intramolecular dehydration of the 3a-i with the modified Mitsunobu's reaction, the target flavanones (4a-i) were obtained. Moreover, the reaction of 1 and 2 at the same conditions but at reflux gave flavanones in one pot with good yields.
- Chen, Po-Yuan,Wang, Tzu-Pin,Chiang, Michael Y.,Huang, Keng-Shian,Tzeng, Cherng-Chyi,Chen, Yi-Long,Wang, Eng-Chi
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p. 4155 - 4160
(2011/06/26)
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- An efficient catalytic synthesis of flavanones under green conditions
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An efficient and "green" catalytic conversion of 2′-hydroxychalcones to flavanones in 15 min in the presence of a simple amino acid and a base at room temperature is reported. Liquiritigenin was also efficiently synthesised under these conditions.
- Jiang, Heyan,Zheng, Xuxu,Yin, Zhongyi,Xie, Jingjing
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experimental part
p. 220 - 221
(2011/07/29)
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- Direct synthesis and catalytic reactivity of highly ordered large-pore methylaminopropyl-functionalized SBA-15 materials
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Highly ordered large-pore SBA-15 materials functionalized with a high loading of amino groups were synthesized for the first time by co-condensation of tetraethyl orthosilicate (TEOS) and [3-(methylamino)propyl]trimethoxysilane (MAPTMS) using an amphiphilic block copolymer. Addition of inorganic salt to the initial mixture greatly enhanced the mesostructure ordering and stability of the mesoporous materials. The materials thus obtained showed high catalytic activity and selectivity for the synthesis of flavanones by means of the Claisen-Schmidt condensation in the absence of solvent. CSIRO 2005.
- Wang, Xueguang,Cheng, Soofin
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p. 507 - 510
(2007/10/03)
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- Synthesis of flavanones using nanocrystalline MgO
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The design and development of a truly nano heterogeneous catalyst for the Claisen-Schmidt condensation (CSC) of benzaldehydes with 2-hydroxyacetophenone to yield substituted chalcones followed by isomerization to afford flavanones with excellent yields and selectivity is described.
- Choudary,Ranganath,Yadav, Jagajit,Lakshmi Kantam
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p. 1369 - 1371
(2007/10/03)
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- New synthesis of flavanones catalyzed by L-proline
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L-Proline is utilized as an efficient organocatalyst for the synthesis of substituted flavanones and chalcones in good yields. The efficiency of the catalyst was proved with a variety of substrates ranging from electron-deficient to electron-rich aryl aldehydes and 2-hydroxyacetophenones.
- Chandrasekhar,Vijeender,Venkatram Reddy
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p. 6991 - 6993
(2007/10/03)
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- Base Catalysis for Fine Chemicals Production: Claisen-Schmidt Condensation on Zeolites and Hydrotalcites for Production of Chalcones and Flavanones of Pharmaceutical Interest
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Chalcones and flavanones of commercial interest have been obtained with high yields and selectivities using solid base catalysts derived from hydrotalcites.The Al/(Al + Mg) ratio and hydrotalcite crystallite size are important parameters controlling catalyst activity.These catalysts give better results than acid- (HY) or alkaline-exchanged Y zeolites.An optimized hydrotalcite shows excellent catalytic properties for the synthesis of 2',4,4'-trimethoxychalcone (Vesidryl), a product of pharmaceutical interest.The reactivity of substituted acetophenones and benzaldehyde follows the Hammet correlation.In addition to electronic effects, geometrical effects can also play a role in the reactivity of substituted acetophenones and benzaldehyde.
- Climent, M. J.,Corma, A.,Iborra, S.,Primo, J.
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- ABNORMAL BASE CATALYSED REACTION OF FORMALDEHYDE AND BENZALDEHYDES WITH 1-(2-HYDROXYPHENYL)-3-PHENYL-1,3-PROPANEDIONE
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1-(2-Hydroxyphenyl)-3-phenyl-1,3-propanedione (1a) reacts with formaldehyde in the presence of different 1-arylpiperazines (2) to form (1:1) inclusion compounds (3) which on column chromatographic separation yield 4,5;11,12-dibenzo-7-hydroxymethyl-1,3-dioxa-6,10-dioxo-7,9 diphenylcyclododecane (4) and the corresponding 2. 1 react with formaldehyde in the presence of triethylamine to form 3-aroyl-3-(2,3-dihydro-4H-1-benzopyran-4-one-3-ylmethyl)-2,3-dihydro-4H-1-benzopyran-4-one (5) along with benzoic acids and with bezaldehydes in the presence of a base to give 2-aryl-2,3-dihydro-4H-1-benzopyran-4-one (6)
- Joglekar, S. J.,Samant, S. D.
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p. 241 - 244
(2007/10/02)
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- Cyclization of Substituted 2'-Hydroxychalcones to Flavanones. Solvent and Isotope Effects
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The kinetic isotope effects on the cyclization of substituted 2'-hydroxychalcones (R=3-hydroxy, 4'-hydroxy, 4,4'-dihydroxy, 4'-hydroxy-4-nitro, 4-nitro, or 5'-methyl) into the corresponding substituted flavanones have been measured in water and/or methanol.The pronounced isotope effects observed are consistent with the slow rupture of a bond to hydrogen.The effect of the medium permittivity on the rate of cyclization of 2'-hydroxy, 2',4-dihydroxy-, and 2',4'-dihydroxychalcones have been also studied in several mixed solvents and the observed dependence is consistent with a reaction between one ion and one dipole.These results confirm a mechanism that involves general acid attack of the ionized form of the 2'-hydroxychalcones, concerted rotation through the CO-Cα bond, and annelation to the flavanone.
- Furlong, Jorge J. P.,Nudelman, N. Sbarbati
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p. 1213 - 1218
(2007/10/02)
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- Mechanism of Cyclization of Substituted 2'-Hydroxychalcones to Flavanones
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The conversion of 2'-hydroxy- (3), 2',4'-dihydroxy- (4), 2',3'-dihydroxy- (5), and 2',4-dihydroxy-chalcone (6) in aqueous alkali; and of (3) and 2'-hydroxy-4-nitrochalcone (7) in alkaline methanolic medium into the corresponding substituted flavanones has been studied kinetically and spectroscopically.It has been found that results from both methods are consistent with the existence of chalcones in the trans-s-cis conformation and indicate a mechanism that involves general acid attack to the ionized form of the 2'-hydroxychalcones, rotation through the CO-Cα bond and annelation to the flavanone.
- Furlong, Jorge J. P.,Nudelman, N. Sbarbati
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p. 633 - 640
(2007/10/02)
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