- A CHALCONE GLYCOSIDE FROM ACACIA DEALBATA
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A new yellow pigment isolated from the flowers of Acacia dealbata has been shown to be chalcononaringenin 2'-4)-xyloside> by chemical and spectroscopic methods. - Key Word Index - Acacia dealbata; Leguminosae; flowers; 4,2',4',6'-tetrahydroxychalcone 2'-4)-xyloside>.
- Imperato, Filippo
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- Effect of naringenin and its derivatives on the probing behavior of myzus persicae (Sulz.)
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Substances that alter insect behavior have attracted a lot of attention as potential crop protection agents. Naringenin (5,7,40-trihydroxyflavanone) is a naturally occurring bioactive flavanone. We evaluated the influence of naringenin on aphid activities during individual phases of probing and feeding and the effect of structural modifications of naringenin on its activity towards aphids. We monitored the probing behavior of Myzus persicae (Sulz.) (Hemiptera: Aphididae) using the Electrical Penetration Graph (EPG) technique. The chemical modifications were the substitution of hydrogen atoms with methyl, ethyl or pentyl groups and the replacement of the carbonyl group in naringenin and its derivatives with an oxime moiety. Depending on the substituents, the activity of naringenin-derived compounds varied in potency and mode of action. Naringenin was an attractant of moderate activity, which enhanced sap ingestion. The naringenin derivative with two methyl groups-7,40-di-O-methylnaringenin-was a deterrent, which hindered aphid probing in non-phloem tissues. Naringenin oxime derivatives with methyl substituents-7,40-di-O-methylnaringenin oxime, 7-O-methylnaringenin oxime, and 5,7,40-tri-O-methylnaringenin oxime-and the derivative with a pentyl substituent-7-O-pentylnaringenin oxime-were strong attractants which stimulated aphid probing in non-phloem tissues and the ingestion of phloem sap.
- Aniol, Miroslaw,Gabrys, Beata,Kordan, Bozena,Kozlowska, Joanna,Stec, Katarzyna,Wróblewska-Kurdyk, Anna
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- Attrition-enhanced deracemization and absolute asymmetric synthesis of flavanones from prochiral precursors
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Seven racemic 5,7-dimethoxyflavanones afforded conglomerate crystals upon recrystallization from a solvent. Three methodologies were investigated to achieve asymmetric transformation based on dynamic crystallization of the chiral conglomerate system. The first was chiral symmetry breaking of racemic flavanones by attrition-enhanced deracemization. Continuous suspension of racemic flavanones in a small amount of propanol in the presence of a base (1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)) and glass beads promoted chiral symmetry breaking and converted the flavanones to crystals of (+)- or (-)-enantiomers with 78 to 99% ee. The second method involved cyclization of the intermediate aldol product to give optically active flavanone with 90% ee involving a reversible oxa-Michael addition reaction with attrition-enhanced deracemization. The third was a reaction starting from prochiral 2-hydroxy-4,6-dimethoxyacetophenone and 2-naphthaldehyde under basic conditions, which gave the corresponding flavanone in 89% ee.
- Kasashima, Yoshio,Mino, Takashi,Sakamoto, Masami,Shimizu, Waku,Uemura, Naohiro,Yoshida, Yasushi
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p. 5676 - 5681
(2020/10/13)
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- Synthesis of Flavanones via Palladium(II)-Catalyzed One-Pot β-Arylation of Chromanones with Arylboronic Acids
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A total of 47 flavanones were expediently synthesized via one-pot β-arylation of chromanones, a class of simple ketones possessing chemically unactivated β sites, with arylboronic acids via tandem palladium(II) catalysis. This reaction provides a novel route to various flavanones, including natural products such as naringenin trimethyl ether, in yields up to 92percent.
- Cho, Yang Yil,Jang, Hyu Jeong,Kim, Dong Hwan,Kim, Nam Yong,Kim, Nam-Jung,Kim, Young Min,Lee, Soo Jin,Lee, Yong Sup,Park, Boyoung Y.,Son, Seung Hwan,Yoo, Hyung-Seok
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p. 10012 - 10023
(2019/08/30)
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- Total synthesis of agalloside, isolated from: Aquilaria agallocha, by the 5-O-glycosylation of flavan
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Agalloside (1) is a neural stem cell differentiation activator isolated from Aquilaria agallocha by our group using Hes1 immobilized beads. We conducted the first total synthesis of agalloside (1) via the 5-O-glycosylation of flavan 25 using glycosyl fluoride 20 in the presence of BF3·Et2O. Subsequent oxidation with DDQ to flavanone 2 and deprotection successively provided agalloside (1). This synthetic strategy holds promise for use in the synthesis of 5-O-glycosylated flavonoids. The synthesized agalloside (1) accelerated neural stem cell differentiation, which is a result comparable to that for the naturally occurring compound 1.
- Arai, Midori A.,Yamaguchi, Yumi,Ishibashi, Masami
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p. 5025 - 5032
(2017/07/10)
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- Practical synthesis of naringenin
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Two routes for the synthesis of the flavanone naringenin are described. In the first, 3,5-dimethoxyphenol is converted to 2-hydroxy- 4,6-dimethoxyacetophenone and then by condensation with anisaldehyde to 2′-hydroxy-4,4′,6′-trimethoxychalcone. The chalcone is then cyclised with aqueous hydrochloric acid and demethylated with pyridine hydrochloride to form naringenin in 45% overall yield. The condensation of 2-hydroxy-4,6-dimethoxyacetophenone with anisaldehyde could also directly produce 4′,5,7-trimethoxyflavanone, which was then converted into naringenin in 60% overall yield. In the second route, a single step for the preparation of the chalcone is used in which 1,3,5-trimethoxybenzene is acylated with p-methoxycinnamic acid. Although the synthesis of naringenin is achieved in a lower overall yield of 29%, the process is simpler.
- Wang, Qian,Yang, Jian,Zhang, Xiang-Ming,Zhou, Lei,Liao, Xia-Li,Yang, Bo
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p. 455 - 457
(2015/11/03)
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- A novel synthesis of naringenin and related flavanones
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Efficient methods are reported for the preparation of naringenin (4',5,7-trihydroxyflavanone) which could be easily scaled-up. They have been applied to three other flavanones (6.hydroxyflavanone, 6,4'-dihydroxyflavanone, 6,3',4'-trihydroxyflavanone) suitably.
- Cui, Wei,Zhang, Ji,Wang, Qian,Gao, Kai,Zhang, Wei,Yang, Jian
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p. 686 - 689
(2015/02/19)
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- A practical access to highly enantiomerically pure flavanones by catalytic asymmetric transfer hydrogenation
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A surprisingly selective, non-enzymatic kinetic resolution of readily available, racemic β-chiral ketones enabled the title process, which was applied to a rapid synthesis of several bioactive flavanones in virtually enantiopure form (see scheme; MOM=methoxymethyl, Ts=p-toluenesulfonyl). Copyright
- Lemke, Marie-Kristin,Schwab, Pia,Fischer, Petra,Tischer, Sandra,Witt, Morris,Noehringer, Laurence,Rogachev, Victor,Jaeger, Anne,Kataeva, Olga,Froehlich, Roland,Metz, Peter
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supporting information
p. 11651 - 11655
(2013/11/06)
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- Regioselective iodination of flavonoids by N-iodosuccinimide under neutral conditions
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Regioselective synthesis of C-6 and C-8 monoiodo flavonoids, which are important intermediates for the synthesis of flavonoid natural products and drug molecules, was achieved by iodination of suitably alkylated flavonoids with N-iodosuccinimide (NIS) in DMF. The iodination gives either a C-6 or C-8 iodo flavonoid in high yield, depending on the protection pattern of the C-5 and C-7 OH groups. The mild and neutral conditions render this novel protocol particularly useful for the regioselective iodination of acid-sensitive substrates.
- Lu, Kui,Chu, Jie,Wang, Haomeng,Fu, Xiaoli,Quan, Dewu,Ding, Hongxia,Yao, Qingwei,Yu, Peng
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supporting information
p. 6345 - 6348
(2013/11/06)
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- Cytotoxicity against KB and NCI-H187 cell lines of modified flavonoids from Kaempferia parviflora
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Flavones 1-4 isolated from Kaempferia parviflora were used for structural modification. Sixteen flavonoid derivatives, including four new derivatives, were synthesized and evaluated for cytotoxicity against KB and NCI-H187 cell lines. Flavanones 2a-4a demonstrated higher cytotoxic activity than the parent compounds. Cytotoxicity against KB cell line of oxime 1c was about 7 times higher than the ellipticine standard. Interestingly, oximes 1c and 2c exhibited highly potent cytotoxicity against NCI-H187 cell line with IC50 values of 0.014 and 0.23 μM, respectively. Oximes 4c and 5c showed strong cytotoxicity against NCI-H187 cell line with IC50 values of 4.04 and 2.32 μM, respectively.
- Yenjai, Chavi,Wanich, Suchana
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supporting information; experimental part
p. 2821 - 2823
(2010/08/06)
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- Silica gel supported TaBr5: New catalyst for the facile and rapid cyclization of 2′-aminochalcones to the corresponding 2-aryl-2,3-dihydroquinolin-4(1H)-ones under solvent-free conditions
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Silica gel supported TaBr5 (5-10 mol %) is a new solid-support catalyst that can be used under solvent-free conditions for the facile and efficient isomerization of 2′-aminochalcones to the corresponding 2-aryl-2,3-dihydroquinolin-4(1H)-ones. The catalyst is easily prepared, stable and employed under environmentally friendly conditions.
- Ahmed, Naseem,Van Lier, Johan E.
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p. 2725 - 2729
(2007/10/03)
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- (±)-Diinsininone: made nature's way
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We report the synthesis of diinsininone (33), the aglycone of (±)-diinsinin (2). Thereby, we complete the first construction of a proanthocyanidin (PA) type-A compound incorporating a [3.3.1]-bicyclic ketal as its characteristic core. Our strategy utilizes a coupling between a benzopyrilium salt and a flavanone that proves applicable to other PA type-A compounds. During this undertaking, treatment of naringenin (9) with 2-iodoxybenzoic acid (IBX) followed by reductive work-up affords eriodictyol (10). This reactivity mirrors that of catechol hydroxylase (F3H) found in the flavonoid pathway. Other interesting transformations include the formation of flavonoids through an ortho-quinone methide (o-QM) cycloaddition-oxidation sequence and regioselective β-glycosidations of several unprotected flavanones suggesting a likely synthesis of 2 from the aglycone 33.
- Selenski, Carolyn,Pettus, Thomas R.R.
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p. 5298 - 5307
(2007/10/03)
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- A simple biomimetic synthesis of dl-chamaejasmine, a unique 3,3′-biflavanone
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(Chemical Equation Presented) The first chemical synthesis of dl-chamaejasmine (1), a structurally unique 3,3′-biflavanone natural product, was achieved as shown above, by a two-step sequence starting from trimethyl ether derivatives of 3-iodonaringenin (cis + trans) involving (i) metallic lanthanum-mediated reductive dimerization in refluxing THF and (ii) global demethylation with BBr3 in CH2Cl2. This synthesis represents a generally applicable biomimetic (reductive) radical dimerization approach to the 3,3′-biflavonoids.
- Li, Wei-Dong Z.,Ma, Bao-Chun
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p. 271 - 274
(2007/10/03)
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- Synthesis of isoflavones containing naturally occurring substitution pattern by oxidative rearrangement of respective flavanones using thallium(III) p-tosylate
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Claisen condensation of substituted 2′-hydroxyacetophenones 1a-c with aromatic aldehydes affords respective substituted 2′-hydroxychalcones 2a-n which on base catalyzed cyclization in pyridine:methanol:water (1:1:1) give respective flavanones 3a-n. The oxidative rearrangement of flavanones with thallium(III) p-tosylate furnishes respective isoflavones 4a-n in overall 62-72% yields starting from 1. The present methodology has been successfully applied for the synthesis of naturally occurring isoflavones such as di-O-methyldaidzein 4a, cabruvin 4b, pseudobabtigenin methylether 4d, 5,7-dimethoxyisoflavone 4f, 5,7,4′-trimethoxyisoflavone 4g, derrustone 4i, 7,8,3′,4′- tetramethoxyisoflavone 41, purpuranin-A 4m and 7,8,3′,4′,5′- pentamethoxyisoflavone 4n and thus the first synthesis of 4n is reported.
- Singh, Om V.,Muthukrishnan,Sunderavadivelu
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p. 2575 - 2581
(2007/10/03)
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- Novel flavanoids as chemotherapeutic, chemopreventive, and antiangiogenic agents
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Novel compounds are useful as chemotherapeutic, chemopreventative, and antiangiogenic agents are provided. The compounds are flavanoids, including flavanones, flavanols, and chalcones. The compounds have the structure of formula (I) 1wherein R1 through R3 and R5 through R11 are defined herein, and α, β, and γ are optional bonds, providing that when α is absent, β is present, and when β is absent, α is present. When α is present, preferred R4 moieties are selected from O, S, NH and CH2, and when α is absent, preferred R4 groups are selected from OH, SH, NH2 and CH3. When γ is present, the preferred R5 substituent is O, while when γ is absent, the preferred R5 substituent is OH. Pharmaceutical compositions are provided as well, as are methods of synthesis and use.
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- An improved procedure for the isomerisation of 2′-hydroxysubstituted chalcones to flavanones using silica supported-BiCl3 under dry conditions
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The isomerisation of 2′-hydroxychalcones to their corresponding flavanones, in good to excellent yield using silica supported-Bi(III) chloride as a catalyst under dry conditions at 70-80°C is reported.
- Ahmed, Naseem,Ansari
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p. 572 - 573
(2007/10/03)
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- Flavonoid derivatives as organometallic bioprobes
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The synthesis of organoiron derivatives of biologically active flavonoids is described. Lithium enolates of functionalised protected acetophenones and metallated derivatives of substituted aromatic rings have been employed as nucleophiles in combination with tricarbonyl(η5-cyclohexadienyl)iron electrophiles. Products have been converted into flavonoid and chalcone derivatives. Enolates generated from protected flavanones have also been used in nucleophile addition reactions, and a one-pot in situ protection, nucleophile addition, deprotection sequence is reported.
- Anson, Christopher E.,Creaser, Colin S.,Malkov, Andrej V.,Mojovic, Ljubica,Stephenson, G. Richard
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p. 101 - 122
(2007/10/03)
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- Novel flavanoids as chemotherapeutic, chemopreventive, and antiangiogenic agents
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Novel compounds useful as chemotherapeutic, chemopreventive, and antiangiogenic agents are provided. The compounds are flavanoids, including flavanones, flavanols, and chalcones. The compounds have the structure of formula (I) wherein R1 through R3 and R5 through R11 are defined herein, and α, β and γ are optional bonds, providing that when α is absent, β is present, and when β is absent, α is present. When α is present, preferred R4 moieties are selected from O, S, NH and CH2, and when α is absent, preferred R4 groups are selected from OH, SH, NH2 and CH3. When γ is present, the preferred R5 substituent is O, while when γ is absent, the preferred R5 substituent is OH. Pharmaceutical compositions are provided as well, as are methods of synthesis and use.
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- A new and efficient Baeyer-Villiger rearrangement of flavanone derivatives by the methyltrioxorhenium/H2O2 catalytic system
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The catalytic Baeyer-Villiger rearrangement of flavanones is described by the use of the homogeneous methyltrioxorhenium (MTO)/H2O2 system. In these experimental conditions 3,4-dihydro-4-phenyl-1,5-benzodioxepin-2-ones and previously
- Bernini, Roberta,Mincione, Enrico,Cortese, Manuela,Aliotta, Giovanni,Oliva, Anna,Saladino, Raffaele
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p. 5401 - 5404
(2007/10/03)
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- ONE-STEP CONVERSION OF FLAVANONES INTO ISOFLAVANONES: A NEW FACILE BIOMIMETIC SYNTHESIS OF ISOFLAVONES
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One-step chemical conversion of flavanones into isoflavones by use of thallium trinitrate (TTN) is reported, and the mechanism of a 2,3-aryl migration in this reaction is discussed in relation to in vivo rearrangement process of flavanone precursors in the isoflavone biosynthesis.
- Kinoshita, Takeshi,Ichinose, Koji,Sankawa, Ushio
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p. 7355 - 7356
(2007/10/02)
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- Reaction of 2'-Hydroxychalcones with Methylene Iodide: A Novel Formation of 3-Aryl-2,5-dihydro-5-oxo-1-benzoxepins
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2'-Hydroxychalcones (1a-c) bearing a methoxy group at 4'-position react with methylene iodide in the presence of K2CO3 and Me2CO for 38 hr to give besides the corresponding flavanones (2a-c), 3-aryl-2,5-dihydro-5-oxo-1-benzoxepins (3a-c).However, the 2'-hydroxychalcones (1d and 1e), having 4',6'-dimethoxy groups react sluggishly requiring 170 hr and also the product is a mixture of not only the corresponding flavanones (2d,e) and benzoxepinones (3d,e) as above but also of the biscompounds (4a,b) having intermolecular methylenedioxy group.The structures of benzoxepinones (3) have been established by their PMR, 13C-NMR and mass spectral data.Their formation has been rationalised via the formation of cyclopropane ring (5), followed by ring cleavage and H- shift.
- Jain, A. C.,Nayyar, Naresh K.,Sharma, B. N.
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p. 1211 - 1215
(2007/10/02)
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- ANTHOXANTHINS-16
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A number of flavanones such as 4',5,7-trimethoxy- , 3',4'5,7- tetramethoxy-, 3'4',5,5',7- pentamethoxy- , 4,5- dimethoxy- and 3',4',5-trimethoxyflavonones have been synthesized and reduced to the corresponding flavan-4 !- ols using sodium borohydride. The flavan-4 !- ols thus obtained have been converted to the corresponding flavan-4 !- ols by treatment with phosphorous tinbromide followed by alcoholic potassium hydroxide. Stereochemistry of the flavan-4- ols has also been established.
- KAMAT MS,MAHAJAN PY,KULKARNI AB
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p. 119 - 122
(2007/10/08)
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