- Lanthanide bis(trifluoromethanesulfonyl)amides, synthesis, characterization and catalytic activity
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The synthesis of lanthanum, neodymium and ytterbium bis(trifluoromethanesulfonyl)amides, named triflimidates, from acetates, carbonates and oxides is investigated. When the synthesis is performed in water, all the salts contain one molecule of water and the lanthanum and neodymium salts synthesized from the acetates also contain one molecule of acetic acid. After removal of the water and acetic acid in refluxing ethanol, the salts are obtained anhydrous but associated for lanthanum and neodymium, whereas the ytterbium salt is monomeric and volatile. When the synthesis is performed directly in ethanol, the neodymium salt contains two molecules of coordinated ethanol. In non-hazardous solvents, these triflimidates are better catalysts than the analogous triflates toward either Friedel-Crafts acylations, or Fries transpositions or Baeyer-Villiger oxidations. Unexpectedly, the cerium(IV) triflimidate catalyzes the oxidation of aromatic ketones to give the corresponding acids.
- Baudry, Denise Barbier,Dormond, Alain,Duris, Fanny,Bernard, Jean Marie,Desmurs, Jean Roger
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- Manganese triacetate oxidation of methyl 1-hydroxy-2-naphthalene carboxylates
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Manganese-triacetate mediated oxidation of 1-hydroxy-2-napthalene carboxylates in benzene under anhydrous conditions delivers the dimerized product. However, acetoxylation on the ortho- or para-position, or oxidation to quinones occurs on the 1-hydroxy-3-substituted 2-napthalene carboxylates depending on the nature of the substituents when the reaction is carried out in a mixture of acetic acid/acetonitrile.
- Munive, Laura,Gómez-Calvario, Víctor,Olivo, Horacio F.
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- A novel fluorescent probe based on 7,8-benzochromone-3-carbaldehyde-(rhodamine B carbonyl) hydrazone for detection of trivalent cations and Zn2+ in different systems
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In this article, a new fluorescence probe 7,8-benzochromone-3-carbaldehyde- (rhodamine B carbonyl) hydrazone (L) was synthesized, which had been explored to detect Zn2+ and trivalent metal ions M3+ (Al3+, Cr3+ and Fe3+). When the excitation wavelength was 490 nm, L showed high selectivity and high sensitivity to M3+ which was superior to monovalent and divalent metal cations in methanol solution. In EtOH/H2O (15/1, V/V), L showed selective fluorescence response to Zn2+, when the excitation wavelength was set to 425 nm. Furthermore, the detection limits of L for Fe3+, Al3+ and Cr3+ were 2.46 × 10?9 M, 2.54 × 10-9 M and 4.23 × 10-8 M, respectively. And the detection limit of L for Zn2+ was calculated to be 1.45 × 10-7 M. The coordination ratio between L and M3+ was determined from the Job's plot (fluorescent spectrum) to be 2:1 and the coordination ratio of L and Zn2+ was 1:1. Additionally, L might be used as a colorimetric probe of Cu2+ in EtOH/H2O (15/1, V/V) solution., which could be observed with the naked eye from colorless to red in the presence of Cu2+.
- Sun, Jie,Li, Tian-rong,Yang, Zheng-yin
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- Synthesis and supramolecular structure of 2-acetyl-1-naphthol
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2-Acetyl-1-naphthol with the molecular formula C12H10O2, is stabilized by intramolecular O2-H2...O1 hydrogen bond forming a six-membered ring, nearly planar with the naphthone ring and the distances from C1 atom of acetyl group to mean plane of the three six-membered ring is 0.112(3) ?. Moreover, the structure is stabilized by intermolecular C-H...p and p-p stacking interactions.
- Su, Qiong,Zhang, Xin-Ying,Zhang, Yu-Jie,Zhao, Li,Wang, Li,Wang, Yan-Bin
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- Synthesis and structure-activity relationship studies of α-naphthoflavone derivatives as CYP1B1 inhibitors
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Cytochrome P450 1B1(CYP1B1) has been recognized as an important target for cancer prevention and drug resistance reversal. In order to obtain potent and selective CYP1B1 inhibitors, a series of forty-one α-naphthoflavone (ANF) derivatives were synthesized, characterized, and evaluated for CYP1B1, CYP1A1 and CYP1A2 inhibitory activities. A closure look into the structure-activity relationship for the inhibitory effects on CYP1B1 indicated that modification of the C ring of ANF would decrease the CYP1B1 inhibitory potency, while incorporation of substituent(s) into the different positions of the B ring yielded analogues with varying CYP1B1 inhibitory capacity. Among these derivatives, compounds 9e and 9j were identified as the most potent two selective CYP1B1 inhibitors with IC50 values of 0.49 and 0.52 nM, respectively, which were 10-fold more potent than the lead compound ANF. In addition, molecular docking and a reasonable 3D-QSAR (three-dimensional quantitative structure-activity relationship) study were performed to provide a better understanding of the key structural features influencing the CYP1B1 inhibitory activity. The results achieved in this study would lay a foundation for future development of selective, potent, low-toxic and water-soluble CYP1B1 inhibitors.
- Dong, Jinyun,Wang, Zengtao,Cui, Jiahua,Meng, Qingqing,Li, Shaoshun
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- Benzoflavone derivatives as potent antihyperuricemic agents
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Two series of benzoflavone derivatives were rationally designed, synthesized and evaluated for their xanthine oxidase (XO) inhibitory potential. Among both series, eight compounds (NF-2, NF-4, NF-9, NF-12, NF-16, NF-25, NF-28, and NF-32) were found to exert significant XO inhibition with IC50 values lower than 10 μM. Enzyme kinetic studies revealed that the most potent benzoflavone derivatives (NF-4 and NF-28) are mixed type inhibitors of the XO enzyme. Molecular modeling studies were also performed to investigate the binding interactions of these molecules (NF-4 and NF-28) with the amino acid residues present in the active site of the enzyme. Docking results confirmed that their favorable binding conformations in the active site of XO can completely block the catalytic activity of the enzyme. Benzoflavone derivatives exhibiting potent XO enzyme inhibition also showed promising results in a hyperuricemic mice model when tested in vivo.
- Singh, Jatinder V.,Mal, Gurbachan,Kaur, Gurleen,Gupta, Manish K.,Singh, Amritpal,Nepali, Kunal,Singh, Harbinder,Sharma, Sahil,Bedi, S. Preet Mohinder
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p. 128 - 147
(2019/01/30)
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- Directed Hydroxylation of sp2 and sp3 C-H Bonds Using Stoichiometric Amounts of Cu and H2O2
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The use of copper for C-H bond functionalization, compared to other metals, is relatively unexplored. Herein, we report a synthetic protocol for the regioselective hydroxylation of sp2 and sp3 C-H bonds using a directing group, stoichiometric amounts of Cu and H2O2. A wide array of aromatic ketones and aldehydes are oxidized in the carbonyl γ-position with remarkable yields. We also expanded this methodology to hydroxylate the β-position of alkylic ketones. Spectroscopic characterization, kinetics, and density functional theory calculations point toward the involvement of a mononuclear LCuII(OOH) species, which oxidizes the aromatic sp2 C-H bonds via a concerted heterolytic O-O bond cleavage with concomitant electrophilic attack on the arene system.
- Trammell, Rachel,D'Amore, Lorenzo,Cordova, Alexandra,Polunin, Pavel,Xie, Nan,Siegler, Maxime A.,Belanzoni, Paola,Swart, Marcel,Garcia-Bosch, Isaac
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p. 7584 - 7592
(2019/06/11)
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- ATF3 INDUCTION COMPOUNDS
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Provided are compounds for treating and/or preventing obesity and obesity-related disorders. Particularly, provided are chromanone derivatives used as ATF3 inducer and for treating and/or preventing obesity and obesity-related disorders such as heart disease, hypertension, hyperlipidemia and diabetes.
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- Benzoflavones as cholesterol esterase inhibitors: Synthesis, biological evaluation and docking studies
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A library of forty 7,8-benzoflavone derivatives was synthesized and evaluated for their inhibitory potential against cholesterol esterase (CEase). Among all the synthesized compounds seven benzoflavone derivatives (A-7, A-8, A-10, A-11, A-12, A-13, A-15) exhibited significant inhibition against CEase in in vitro enzymatic assay. Compound A-12 showed the most promising activity with IC50value of 0.78?nM against cholesterol esterase. Enzyme kinetic studies carried out for A-12, revealed its mixed-type inhibition approach. Molecular protein–ligand docking studies were also performed to figure out the key binding interactions of A-12 with the amino acid residues of the enzyme's active site. The A-12 fits well at the catalytic site and is stabilized by hydrophobic interactions. It completely blocks the catalytic assembly of CEase and prevents it to participate in ester hydrolysis mechanism. The favorable binding conformation of A-12 suggests its prevailing role as CEase inhibitor.
- Singh, Harbinder,Singh, Jatinder Vir,Gupta, Manish K.,Singh, Palwinder,Sharma, Sahil,Nepali, Kunal,Bedi, Preet Mohinder S.
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supporting information
p. 850 - 854
(2017/02/12)
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- Lithiation of a silyl ether: Formation of an ortho-fries hydroxyketone
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A hydroxy-directed alkylation of an N,N-diethylarylamide using CIPE-assisted α-silyl carbanions (CIPE=complex-induced proximity effect) has been developed using a simple reagent combination of LDA (lithium diisopropylamide) and chlorosilane. A study of the mechanism, and the application of the procedure to an anionic Snieckus-Fries rearrangement for a highly efficient synthesis of the potent phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002, are reported.
- Lo, Hong-Jay,Lin, Chin-Yin,Tseng, Mei-Chun,Chein, Rong-Jie
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p. 9026 - 9029
(2014/09/17)
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- Synthesis and evaluation of naphthoflavones as a new class of non purine xanthine oxidase inhibitors This Letter is dedicated to Dr. K. L. Dhar on the occasion of his 78th birthday.
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In view of reported xanthine oxidase inhibitory potential of naphthopyrans and flavones, naphthoflavones as hybrids of the two were designed, synthesized and evaluated for in vitro xanthine oxidase inhibitory activity in the present study. The results of the assay revealed that the naphthoflavones possess promising inhibitory potential against the enzyme with IC50 values ranging from 0.62 to 41.2 μM. Structure activity relationship indicated that the nature and placement of substituents on the phenyl ring at 2nd position remarkably influences the inhibitory activity. Substitution of halo and nitro groups at ortho and para position of the phenyl ring (2nd position) remarkably favored the activity. NF-4 with p-fluoro phenyl ring was the most potent inhibitor with IC50 value of 0.62 μM. Enzyme kinetics study was also performed to investigate the inhibition mechanism and it was found that the naphthoflavones displayed mixed type inhibition. The basis of significant inhibition of xanthine oxidase by NF-4 was rationalized by molecular modeling studies.
- Singh, Harbinder,Sharma, Sahil,Ojha, Ritu,Gupta, Manish K.,Nepali, Kunal,Bedi
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supporting information
p. 4192 - 4197
(2014/09/17)
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- Synthesis and characterization of 3-(1-hydroxy naphthalene-2-yl)-5-(furan- 2-yl)-1-substituted pyrazolines
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2-acetyl-1-naphthol 2 is prepared by Modified Nenchi's method which on treatment with furfuraldehyde and KOH gives 1-(1-hydroxy naphthalen-2-yl)-3- (furan-2-yl) prop-2-ene-1-ones 3 in excellent yield. The chalcone 3 when subjected to hydrazine/phenyl hydrazine/semicarbazide/2,4 dinitro phenyl hydrazine/isonicotinic acid hydrazide in DMF solvent gives 3-(1-hydroxy naphthalene-2-yl)-5-(furan-2-yl)-1-substituted pyrazolines 4, 5, 6, 7 and 8 in 35-45% yield. The structural assignments to the compounds 4, 5, 6, 7 and 8 are based on their elemental analysis and spectral data.
- Bhandarkar
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p. 361 - 363
(2014/06/23)
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- Pd-catalyzed sequential C-C bond formation and cleavage: Evidence for an unexpected generation of arylpalladium(II) species
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A Pd(II)-catalyzed reaction engaging alkenyl β-keto esters is reported that leads to the formation of 1-naphthols and an unexpected generation of arylpalladium(II) species. Interception of the in situ generated arylpalladium(II) species in a Mizoroki-Heck reaction, together with additional mechanistic studies, provided strong evidence in support of the first aromatization-driven β-carbon elimination process. A single Pd catalyst served to promote a series of both C-C bond forming and cleavage events in an unprecedented manner.
- Youn, So Won,Kim, Byung Seok,Jagdale, Arun R.
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supporting information; experimental part
p. 11308 - 11311
(2012/08/28)
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- Synthesis of aryl-substituted naphthalenes by chemoselective Suzuki-Miyaura reactions of bromo-trifluoromethanesulfonyloxy-naphthalenes. Influence of steric and electronic parameters
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Chemoselective Suzuki-Miyaura reactions of 2-bromo-1- (trifluoromethanesulfonyloxy)naphthalene, 1-bromo-2- (trifluoromethanesulfonyloxy) naphthalene and 2-acetyl-4-bromo-1- (trifluoromethanesulfonyloxy)naphthalene, which are all readily available from the corresponding tetralone derivatives, afforded a variety of mono- and diarylnaphthalenes. The reactions generally proceed with excellent chemoselectivity in favour of the bromide position, no matter whether the bromide is located at position 1 or 2 of the naphthalene or whether the carbon attached to the triflate group is electronically more deficient by the presence of a neighbouring acetyl group.
- Hassan, Zahid,Hussain, Munawar,Villinger, Alexander,Langer, Peter
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experimental part
p. 6305 - 6313
(2012/08/27)
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- Design, synthesis, structure, and dehydrogenation reactivity of a water soluble o-iodoxybenzoic acid derivative bearing a trimethylammonium group
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5-Trimethylammonio-1, 3-dioxo-1, 3-dihydro-1λ5-benzo[d][1, 2]iodoxol-1-ol anion (AIBX 1a), an o-iodoxybenzoic acid (IBX) derivative having the trimethylammonium moiety on its phenyl ring, possesses very good solubility in water and distinct oxidative properties from IBX, which is demonstrated in the oxidation of various β-keto esters to the corresponding dehydrogenated products using water as cosolvent. The regeneration of AIBX 1a can be easily realized from the reaction mixture due to its good water solubility.2011 American Chemical Society.
- Cui, Li-Qian,Dong, Zhi-Lei,Liu, Kai,Zhang, Chi
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supporting information; scheme or table
p. 6488 - 6491
(2012/02/02)
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- Comparisons of O-acylation and Friedel-Crafts acylation of phenols and acyl chlorides and Fries rearrangement of phenyl esters in trifluoromethanesulfonic acid: Effective synthesis of optically active homotyrosines
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Reactions involving phenol derivatives and acyl chlorides have to be controlled for competitive O-acylations and C-acylations (Friedel-Crafts acylations and Fries rearrangements) in acidic condition. The extent for these reactions in trifluoromethanesulfonic acid (TfOH), which is used as catalyst and solvent, is examined. Although diluted TfOH was needed for effective O-acylation, concentrated TfOH was required for effective C-acylations in mild condition. These results have been applied to the novel synthesis of homotyrosine derivatives. Both Fries rearrangement of N-TFA-Asp(OBn)-OMe and Friedel-Crafts acylation of phenol with N-TFA-Asp(Cl)-OMe in TfOH afforded the homotyrosine skeleton, followed by reduction and deprotection afforded homotyrosines maintaining stereochemistry of Asp as an optically pure form.
- Murashige, Ryo,Hayashi, Yuka,Ohmori, Syo,Torii, Ayuko,Aizu, Yoko,Muto, Yasuyuki,Murai, Yuta,Oda, Yuji,Hashimoto, Makoto
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experimental part
p. 641 - 649
(2011/03/19)
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- Synthesis and anticoccidial activity of 3-(2-(1-methoxynaphthalen-2-yl)-2-oxoethyl) quinazolinone derivatives
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A series of 3-(2-(1-methoxynaphthalen-2-yl)-2-oxoethyl) quinazolinone derivatives (8a-k) were designed and synthesized. Their anticoccidial activities were evaluated against Eimeria tenella in vivo. The results indicated that compounds 8a, 8b and 8e exhibited anticoccidial activity against Eimeria tenella in the chicken's diet with a dose of 18 mg/Kg.
- Zhang, Yuanyuan,Chen, Guangmin,Weng, Yabiao,Li, Renliang,Wang, Yuliang,Wang, Yuzhong
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experimental part
p. 471 - 475
(2011/11/06)
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- New synthetic flavone derivatives induce apoptosis of hepatocarcinoma cells
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Natural flavonoids have broad biological activity, including anticancer. In this study, a series of novel flavone derivatives were synthesized with the substitutions of chlorine, isopropyl, methoxy, and nitro groups on the benzene ring of flavone skeleton to develop effective anticancer agents. Antiproliferative assays showed that the synthesized chemicals possess notable activity against hepatocarcinoma cells (HepG-2); in particular, the compound 6f with chlorine and dimethoxy modifications at the two benzene rings showed an IC50 at 1.1 μM to HepG-2. The 6f also displayed marked anticancer activity towards a panel of cancer cells, including nasopharyngeal carcinoma cells (CNE-2 and CNE-1), breast adenocarcinoma cell (MCF-7), and epithelial carcinoma cells (Hela). Exposing HepG-2 cells to compound 6f at 10 μM induced chromatin condensation, nuclear disassembly, and DNA fragmentation. In 6f-treated HepG-2 cells, the sub-G0 population was remarkably increased; and in these cells, both caspase-8 and caspase-9 activity was significantly increased, which in turn activated caspase-3. In addition, proapoptotic Bax was upregulated by compound 6f while the antiapoptotic Bcl-2 was downregulated. Taken together, our data suggest that the new flavonoid derivative 6f triggers apoptosis through both death-receptor and mitochondria-dependent intrinsic pathways, being a potent therapeutic agent against hepatocarcinoma.
- Liu, Huachen,Dong, Aijun,Gao, Chunmei,Tan, Chunyan,Xie, Zhenhua,Zu, Xuyu,Qu, Long,Jiang, Yuyang
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scheme or table
p. 6322 - 6328
(2010/10/03)
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- Regioselective ortho-acylation of phenol and naphthol derivatives catalyzed by FeCl3 under microwave conditions
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Phenol and naphthol derivatives were subjected to regioselective solvent-free ortho-acylation with organic acids in the presence of FeCl 3 under microwave irradiation. The reactions were complete in a short time, and the products were obtained in high yields.
- Naeimi,Moradi
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body text
p. 1757 - 1759
(2009/09/29)
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- Solvent affected facile synthesis of hydroxynaphthyl ketones: Lewis acids promoted Friedel-Crafts and demethylation reaction
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Hydroxynaphthyl ketones were obtained with high yields under very mild conditions in the presence of AlCl3 via Friedel-Crafts acylation and demethylation from naphthyl ethers. Several Lewis acids were tested, and AlCl3 was the most efficient catalyst. Copyright Taylor & Francis Group, LLC.
- Li, Wan-Mei,Lai, Hu-Qin,Ge, Zhong-Hua,Ding, Cheng-Rong,Zhou, Ying
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p. 1595 - 1601
(2008/02/01)
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- Friedel-Crafts acylation reaction using carboxylic acids as acylating agents
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Dehydrative Friedel-Crafts acylation reaction of aromatic compounds with carboxylic acids as acylating agents was investigated in the presence of Lewis acid- or Br?nsted acid-catalyst. Various metal triflates and bis(trifluoromethanesulfonyl)amides showed catalytic activity at high temperature, among which Eu(NTf2)3 proved to be the most effective and efficiently catalyzed the acylation reaction of alkyl- and alkoxybenzenes with aliphatic and aromatic carboxylic acids at 250 °C. Bi(NTf2)3 was more effective than Eu(NTf2)3 at lower temperature, but proved to be hydrolyzed in the presence of a small amount of water to give HNTf2 and [Bi6O4(OH)4(H2O)6](NTf2)6. The structure of the latter compound was confirmed by a single crystal X-ray analysis. Among five Br?nsted acids, HOTf, HNTf2, HCTf3, TsOH, and Nafion SAC-13, HNTf2 has proved to be the most efficient catalyst and more effective than Eu(NTf2)3 for the acylation of p-xylene with heptanoic acid at 220 °C or lower temperature. HNTf2 catalyzed the acylation of anisole with carboxylic acids in high yields in refluxing toluene with azeotropic removal of water.
- Kawamura, Masato,Cui, Dong-Mei,Shimada, Shigeru
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p. 9201 - 9209
(2007/10/03)
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- Direct acylation of phenol and naphthol derivatives in a mixture of graphite and methanesulfonic acid
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Graphite in methanesulfonic acid is used to prepare o-hydroxyketones by direct acylation of phenol and naphthol derivatives with carboxylic acids. Georg Thieme Verlag Stuttgart.
- Sharghi, Hashem,Hosseini-Sarvari, Mona,Eskandari, Razieh
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p. 2047 - 2052
(2007/10/03)
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- Microwave assisted direct ortho-acylation of phenol and naphthol derivatives by BF3·(C2H5)2O
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The solventless acylation of phenol and naphthol derivatives with various organic acids and BF3·(C2H5) 2O, under microwave conditions, was studied. High yields of the o-acylated products were achieved in a very short time.
- Naeimi, Hossein,Moradi, Leila
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p. 284 - 287
(2008/02/04)
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- Bismuth triflate-catalyzed fries rearrangement of aryl acetates
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Bismuth triflate was found to be an efficient catalyst in the Fries rearrangement of phenyl or 1-naphthyl acetates. Both reactions proceeded smoothly with a catalytic amount of bismuth triflate (10 mol%) to afford the corresponding hydroxyaryl ketone in moderate to good yields in most cases.
- Ollevier, Thierry,Desyroy, Valerie,Asim, Muhammad,Brochu, Marie-Christine
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p. 2794 - 2796
(2007/10/03)
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- Lewis Acid Catalysis in Supercritical Carbon Dioxide. Use of Poly(ethylene glycol) Derivatives and Perfluoroalkylbenzenes As Surfactant Molecules Which Enable Efficient Catalysis in ScCO2
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Lewis acid catalysis in supercritical carbon dioxide (CO2) was investigated. While solubility of most organic materials is low in scCO 2, poly(ethylene glycol) derivatives or perfluoroalkylbenzenes were found to work as surfactants to dissolve organic materials in scCO2. In the presence of these molecules, Lewis acid catalyzed organic reactions such as aldol-, Mannich-, and Friedel-Crafts-type reactions proceeded smoothly in scCO2. Formation of emulsions was observed in these reactions, and the systems were studied in detail.
- Komoto, Ichiro,Kobayashi, Shu
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p. 680 - 688
(2007/10/03)
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- Selective fries rearrangement catalyzed by zinc powder
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Zinc powder in the presence of N,N-dimethylformamide efficiently catalyzes the selective Fries rearrangement of acetylated phenols under microwave heating or with conventional heating using an oil bath. In some cases different products were obtained using microwave heating and conventional heating. Selective migration of the acyl group has been noted with good yields.
- Paul, Satya,Gupta, Monika
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p. 1789 - 1792
(2007/10/03)
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- Improvement of Selectivity in the Fries Rearrangement and Direct Acylation Reactions by Means of P2O5/SiO2 Under Microwave Irradiation in Solvent-Free Media
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P2O5/SiO2 was found to be an efficient new reagent for the Fries rearrangement of acyloxy benzene or naphthalene derivatives and the direct acylation reactions of phenol and naphthol derivatives with carboxylic acids. The reactions proceeded smoothly in the solid state and are highly selective methods for the preparation of the ortho isomers of hydroxyaryl ketones. Microwave irradiation improved the conversion yield to 85-100 percent and the high ortho-regioselectivity of these reactions provides an efficient and versatile procedure for obtaining o-hydroxyaryl ketones in 47-98 percent yield.
- Eshghi, Hossein,Rafie, Mohammad,Gordi, Zinat,Bohloli, Moosa
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p. 1258 - 1270
(2007/10/03)
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- Metal triflates-methanesulfonic acid as new catalytic systems: Application to the Fries rearrangement
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A surprising synergistic effect has been discovered between metal triflates (Mg, Ca, Sc, Cu, Zn, Y, Ln, Bi) and methanesulfonic acid, leading to active catalytic systems for the Fries rearrangement. In particular, the systems based on yttrium and copper(II) triflate proved to be very active and much cheaper than scandium triflate. The efficiency of these systems might result from the catalytic Lewis acid activation of Br?nsted acids.
- Mouhtady, Omar,Gaspard-Iloughmane, Hafida,Roques, Nicolas,Le Roux, Christophe
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p. 6379 - 6382
(2007/10/03)
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- Formylchromone derivatives as a novel class of protein tyrosine phosphatase 1B inhibitors
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Formylchromone inhibits a human protein tyrosine phosphatase PTP1B with a IC50 value of 73 μM. The chemical reactivity of formylchromone was adjusted by substitution at various positions of the formylchromone skeleton. In an initial assessment of the structure-activity relationship, the most potent inhibitor showed an IC50 of 4.3 μM against PTP1B and strong or medium selectivity against other human PTPases, LAR and TC-PTP. This compound, however, was not selective against microbial PTPases, YPTP1 and YOP. The potency and selectivity of the formylchromone derivatives expecting further improvements provides a novel pharmacophore for the design of drugs for the treatmenrt of type 2 diabetes and obesity.
- Shim, Yi Sup,Kim, Ki Chul,Chi, Dae Yoon,Lee, Keun-Hyeung,Cho, Hyeongjin
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p. 2561 - 2563
(2007/10/03)
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- Thermal cross fries acyl and benzoyl migrations from aromatic diesters to phenols
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A study of boron trifluoride etherate catalyzed thermal cross Fries reaction is reported in this paper. Acyl and benzoyl migrations from various aromatic diesters to phenols in dry benzene as solvent takes place selectively and in this, way offers an alternative route to the preparation of different hydroxy acetophenones and benzophenones.
- Thapliyal,Aggarwal
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p. 706 - 708
(2007/10/03)
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- Synthesis of a new naphthol-derivative salen and spectrophotometric study of the thermodynamics and kinetics of its complexation with copper(II) ion in binary dimethylsulfoxide-acetonitrile mixtures
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A synthetic procedure has been developed for the preparation of new salen (2,2′-[1,2-ethanediyl bis (nitriloethylidyne)] bis (1-naphthalenol)). The thermodynamics and kinetics of complexation reaction between the new salen and Cu2+ ion were investigated spectrophotometrically in different dimethylsulfoxide-acetonitrile mixtures. Formation constant of the resulting 1:1 complex was determined from the absorbance-mole ratio data and found to increase with increasing acetonitrile content of the solvent mixtures. Enthalpy and entropy data for complexation were determined from the temperature dependence of the formation constant. In all solvent mixtures, the salen-copper complex is entropy stabilized but enthalpy destabilized. Order of reaction, rate constants and activation parameters for the complexation reaction in different solvent mixtures were also investigated. The Arrhenius plots showed a distinct isokinetic temperature at about 88°C, at which the reaction rate is approximately independent of the solvent composition. Activation parameters are strongly solvent dependent.
- Alizadeh,Ershad,Naeimi,Sharghi,Shamsipur
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p. 915 - 925
(2007/10/03)
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- Ytterbium triflate mediated selective deprotection of acetates
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Ytterbium triflate mediated selective deprotection of acetates in isopropyl alcohol at reflux temperature is reported. Unlike hafnium triflate, under the present reaction conditions aryl acetates also undergo deacetylation instead of Fries migration.
- Sharma,Ilangovan
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p. 1963 - 1965
(2007/10/03)
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- Effect of cyclodextrin complexation on photo-fries rearrangement of naphthyl esters
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Photolysis of β-cyclodextrin inclusion complexes of 1- and 2-naphthyl esters (acetates and benzoates) in aqueous medium, results in rearrangement to give one isomer of acylnaphthol in excess, whereas the solid state irradiation of the cyclodextrin complexes yields selectively one isomer. In addition, formation of cleavage product is totally suppressed. This remarkable selectivity is attributed to specific modes of the complexation of the esters into the β-CD cavity.
- Banu, Habeeb Shayira,Pitchumani, Kasi,Srinivasan, Chockalingam
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p. 9601 - 9610
(2007/10/03)
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- Tandem Fries Reaction-Conjugate Addition under Microwave Irradiation in Dry Media; One-pot Synthesis of Flavanones
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An AlCl3-ZnCl2 mixture supported on silica gel is found to be an efficient medium for the Fries rearrangement of acyloxybenzene or naphthalene derivatives in solvent-free conditions under microwave irradiation.
- Moghaddam, Firouz Matloubi,Ghaffarzadeh, Mohammad,Abdi-Oskoui, Seyed Hossein
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p. 574 - 575
(2007/10/03)
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- Oxidation of 1,3-dicarbonyl compounds using (camphorylsulfonyl)oxaziridines
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The oxidation of 1,3-dicarbonyl compounds with (camphorylsulfonyl)oxaziridines 2 was studied in both cyclic and acyclic systems. Two reaction pathways were identified: Enolate α-hydroxylation and a novel Baeyer-Villiger type oxidation. The Baeyer-Villiger oxidation product was observed only for the ketones and arises via rearrangement of an alkoxy epoxide. Synthetically useful ee's (82-95%) were observed only for enolates of β-ketoesters where the keto group is part of a 6-membered ring.
- Davis, Franklin A.,Liu, Hu,Chen, Bang-Chi,Zhou, Ping
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p. 10481 - 10492
(2007/10/03)
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- Alumina in Methanesulfonic Acid (AMA) as a New Efficient Reagent for Direct Acylation of Phenol Derivatives and Fries Rearrangement. A Convenient Synthesis of o-Hydroxyarylketones
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Alumina in methanesulfonic acid (AMA) is used to prepare o-hydroxyaryl ketones by acylation of phenol and naphthol derivatives with carboxylic acids and the Fries rearrangement of phenolic esters. Mechanistic studies show that the acylation reaction in AMA occurred through an esterification followed by a Fries rearrangement of the phenolic ester by an intermolecular mechanism.
- Sharghi, Hashem,Kaboudin, Babak
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p. 2678 - 2695
(2007/10/03)
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- The Catalytic Fries Rearrangement and o-Acylation Reactions Using Group 3 and 4 Metal Triflates as Catalysts
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Group 3 and 4 metal triflates (Sc(OTf)3, TiCl(OTf)3, Zr(OTf)4, and Hf(OTf)4) were found to be efficient catalysts in the Fries rearrangement of phenyl or 1 -naphthyl acylates. It was also found that the o-acylation (direct acylation) reactions of phenols and 1-naphthols with acid chlorides proceeded smoothly in the presence of the triflates. Both reactions were successfully carried out using small amounts of the triflates (catalytically), and comparison of catalytic activities of these metal triflates in these reactions is discussed.
- Kobayashi, Shue,Moriwaki, Mitsuhiro,Hachiya, Iwao
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p. 267 - 273
(2007/10/03)
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- Hafnium trifluoromethanesulfonate (Hf(OTf)4) as an efficient catalyst in the Fries rearrangement and direct acylation of phenol and naphthol derivatives
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Hafnium trifluoromethanesulfonate (hafnium triflate, Hf(OTf)4) was found to be an efficient catalyst in the Fries rearrangement of acyloxy benzene or naphthalene derivatives. The reactions proceeded smoothly in the presence of 5-20 mol% Hf(OTf)4. Regioselective direct acylation of phenol and naphthol derivatives with acid chlorides was also achieved by using Hf(OTf)4 as a catalyst.
- Kobayashi, Shue,Moriwaki, Mitsuhiro,Hachiya, Iwao
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p. 2053 - 2056
(2007/10/03)
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- Laser flash photolysis and CIDNP studies of 1-naphthyl acetate photo-fries rearrangement
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The steady-state and time-resolved CIDNP and flash photolysis methods were used in a detailed study of the photo-Fries rearrangement of 1-naphthyl acetate (I) in acetonitrile and methanol. The main reaction channel is the decay of I through the excited singlet state with the quantum yields 0.17 ±0.02 in acetonitrile and 0.42 ± 0.04 in methanol at room temperature. The absorption spectra of the naphthoxyl radical and triplet state of 1-naphthyl acetate were detected. The quantum yield of triplet was estimated as 0.4 ±0.2 and 0.35 ± 0.17 in acetonitrile and methanol, respectively. It has been established that the triplet-born radical pairs make a main contribution to the CIDNP of the photo-Fries rearrangement products. The involvement in the process of two different triplet states of I was supposed. The main decay channel of the lowest triplet state is the triplet-triplet annihilation, while the CIDNP of photo-Fries rearrangement products results from the decay of the upper triplet state of I with a lifetime of a few nanoseconds. The kinetics of CIDNP formation in reaction products has been analyzed, and the rate constants of the rearrangement of the preceding intermediates at room temperature have been estimated.
- Gritsan, Nina P.
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p. 4448 - 4458
(2007/10/03)
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- Photo-Fries reaction of naphthyl esters within zeolites
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Photolysis of naphthyl esters within zeolites leads to the photo-Fries rearrangements as in isotropic solution. However, a high level of product selectivity is obtained using 'cation as the key'. A key component for predicting the selectivity of photoreactions within zeolites, namely the location of reactants, is missing at this stage.
- Pitchumani,Warrier,Cui,Weiss,Ramamurthy
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p. 6251 - 6254
(2007/10/03)
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- Catalytic direct C-acylation of phenol and naphthol derivatives using carboxylic acids as acylating reagents
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Direct regioselective C-acylation of phenol and naphthol derivatives was carried out by using carboxylic acids as acylating reagents. The reactions proceeded smoothly in the presence of a catalytic amount of Hf(OTf)4 to afford the corresponding aromatic ketones in good yields.
- Kobayashi, Shu,Moriwaki, Mitsuhiro,Hachiya, Iwao
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p. 4183 - 4186
(2007/10/03)
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- Rare Earth Metal Complexes as Water-Tolerant Lewis Acid Catalysts in Organic Synthesis
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Rare earth metal triflates are stable in aqueous media and can act as Lewis acid catalysts in several carbon-carbon bond forming reactions. This article describes some of these reactions; aldol and Mannich-type reactions in aqueous solution, and Friedel-Crafts acylations and Fries rearrangement in organic solvents. The reactions proceeded smoothly in the presence of a catalytic amount of the triflate under mild conditions. Moreover, the catalysts could be recovered after the reactions were completed and could be reused.
- Kobayashi,Hashiya,Ishitani,Moriwaki,Nagayama
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p. 193 - 202
(2007/10/03)
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- Zirconium tetrachloride as a mediator for ambient temperature ortho-Fries rearrangements
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Zirconium tetrachloride has been found to be an excellent mediator of the Fries reaction. Rearrangements occur at ambient temperature and are highly selective; giving the acetophenone derived from acetyl migration to the sterically least encumbered adjacent carbon.
- Harrowven, David C.,Dainty, Richard F.
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p. 7659 - 7660
(2007/10/03)
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- N-Acylsulphonamides as acyl transferring agents
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N-acylsulphonamides 2a and 2b are found to transfer acyl groups to amino compounds under thermal activation giving the products in moderate to good yields.Acyl transfer is also possible to reactive phenols such as 1-naphthol and resorcinol under ZnCl2 catalysis to produce C-acylated products.
- Mashraqui, Sabir H.,Nirantar, Swati S.,Biswas, Maloyesh M.
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p. 1102 - 1104
(2007/10/03)
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- The Catalytic Fries Rearrangement of Acyloxy Naphthalenes using Scandium Trifluoromethanesulfonate as a Castalyst
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The catalytic Fries rearrangement of acyloxy naphthalenes proceeds smoothly using a small amount of scandium trifluoromethanesulfonate (5 molpercent) to afford the corresponding hydroxynaphthyl ketones in high yields.
- Kobayashi, Shu,Moriwaki, Mitsuhiro,Hachiya, Iwao
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p. 1527 - 1528
(2007/10/02)
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- Stereoselective synthesis of disubstituted naphthalene-1,2- oxides
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Spiroepoxy naphthalenones, obtained from the stereoselective oxidation of 2-hydroxyalkyl-1-naphthols with sodium periodate, were converted to naphthalene-1,2-oxides by reaction with methyllithium followed by Payne rearrangement.
- Tius,Reddy
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p. 859 - 869
(2007/10/02)
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- Claisen rearrangement of allyl ethers of isomeric acetylnaphthols under catalytic conditions
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Claisen rearrangement of the isomeric allyl ethers (1 and 6) of 2-acetyl-1-naphthol and 1-acetyl-2-naphthol has been studied using a Bronsted or protic acid (CF3COOH) and aprotic or Lewis acids as catalysts.The rearrangement of 1 in TFA gives 2-acetyl-1--naphthol (2), 1-acetoxy-2-allylnaphthalene (3) and 2-allyl-1-naphthol (4), but in BF3*OEt2 it resulted in only 4.However, Claisen rearrangement of 1 under Pd(II) mediation furnishes 2-acetyl-4-allyl-1-naphthol (5) and 4.The isomeric ether 6 rearranges in TFA to give 1-allyl-2-naphthol(7) and 2-acetoxy-1-allylnaphthalene (8) while resists rearrangement with BF3*OEt2.However, with Pd(II) it undergoes isomerisation of allyloxy double bond furnishing 1-acetyl-2-(cis-enyloxy)naphthalene (9).All the products have been characterised by their elemental analyses and spectral data (IR, UV, PMR, and mass) and their formation has been rationalised.
- Anjaneyulu, A S R,Isaa, B Meher
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