- Hydroquinone-Based Biarylic Polyphenols as Redox Organocatalysts for Dioxygen Reduction: Dramatic Effect of Orcinol Substituent on the Catalytic Activity
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A series of 18 new biaryls has been synthesized and investigated with regard to their organocatalytic efficiency. They consist of a hydroquinone core linked to a phenol or a resorcinol moiety. It is shown that the resorcinol moiety substituted on its meta position has a strong impact on the catalytic activities of these compounds towards the reduction of dioxygen by diethylhydroxylamine (DEHA) in aqueous medium. While the derivative consisting of the two cores spaced by three methylene units is completely inactive, substitution on the hydroquinone part leads to tremendously active catalysts, especially the biaryl consisting of methoxyhydroquinone-orcinol. Two mechanisms are proposed to explain the dramatic efficiency of the novel hydroquinone-based biarylic polyphenols for the catalytic reduction of dioxygen, both considering the influence of the orcinol moiety on the semiquinone anion intermediate. As a first hypothesis, this substituent could promote its direct reduction by DEHA to regenerate the hydroquinone, which will react again to regenerate the semiquinone. On the other hand, an intramolecular hydrogen bond could enhance the reactivity of the semiquinone anion toward dioxygen by an addition–elimination mechanism. In this case, the elimination would provide the corresponding quinone but, since the reduction of the quinones by DEHA is much slower than the observed kinetics, a reduction by DEHA prior to the elimination has to be considered to generate the semiquinone anion instead of the quinone. (Figure presented.).
- Lebeuf, Rapha?l,Nardello-Rataj, Véronique,Aubry, Jean-Marie
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- A concise and diastereoselective total synthesis of cis and trans-pterocarpans
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A new strategy for the diastereoselective and convergent synthesis of pterocarpans which is able to control the relative stereochemistry of the molecule through allylation of aromatic aldehydes with cyclic allylsiloxanes is described. The Royal Society of
- Jimenez-Gonzalez, Leticia,Alvarez-Corral, Miriam,Munoz-Dorado, Manuel,Rodriguez-Garcia, Ignacio
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- Microwave-assisted organic syntheses: Microwave effect on intramolecular reactions-the Claisen rearrangement of allylphenyl ether and 1-allyloxy-4-methoxybenzene
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This article examined how and the possible effect microwaves may have on intramolecular reactions such as those of the Claisen-type rearrangement carried out in dimethyl sulfoxide (DMSO) solvent and in solvent-free, microwave irradiation conditions. For comparison, the reaction was also performed by conventional heating using an oil bath. 2-Allylphenol was synthesized from allylphenyl ether in DMSO solvent under stirring conditions as a model intramolecular reaction taking place via the Claisen rearrangement using a commercial microwave chemical apparatus together with conventional heating; no enhancement of the reaction occurred. To further examine the influence of microwave irradiation on Claisen rearrangement reactions, we also investigated the transformation of 1-allyloxy-4-methoxybenzene to 2-allyl-4-methoxyphenol under both solvent-free conditions (no stirring) and in DMSO medium; here also no reaction enhancement was observed. This notwithstanding, microwaves did impact the formation of a by-product formed in the latter reaction, which was identified by GC and GC/MS as 4-methoxyphenol, the yield of which was nearly fourfold greater (ca. 6%) under microwave irradiation than under oil-bath heating (ca. 1.5%). The latter suggests that under solvent-free conditions a microwave non-thermal effect influenced the formation of this by-product during the Claisen rearrangement process, contrary to the case where the reaction was performed in DMSO medium for which the yields were identical (ca. 2.5%), regardless of whether the reactant was microwave or oil-bath heated.
- Horikoshi, Satoshi,Watanabe, Tomoki,Kamata, Momoko,Suzuki, Yumiko,Serpone, Nick
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- Evaluation of a nonresonant microwave applicator for continuous-flow chemistry applications
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The concept of a nonresonant microwave applicator for continuous-flow organic chemistry is introduced and evaluated. The frequency of the incident microwave radiation can be adjusted between 2.4 and 2.5 GHz to optimize the energy absorbance. The temperature of the reaction is monitored by five IR sensors, and their signals can be used to automatically adjust the power output from the microwave generator. The heating of several different solvents up to 20 °C above the standard boiling point has been explored. Several different organic reactions have been successfully carried out using a 200 mm × φ 3 mm tubular borosilicate reactor and a flow between 47 and 2120 μL/min. The microwave heating pattern was visualized with an IR camera. The transformations include palladium-catalyzed coupling reactions (oxidative Heck and Suzuki reactions), heterocyclic chemistry (oxathiazolone and Fischer indole synthesis), rearrangement (Claisen), and a Diels-Alder cycloaddition reaction. A scale-out to 57 mmol/h was performed with the Fischer indole reaction.
- Oehrngren, Per,Fardost, Ashkan,Russo, Francesco,Schanche, Jon-Sverre,Fagrell, Magnus,Larhed, Mats
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- Pharmacological and SAR analysis of the LINS01 compounds at the human histamine H1, H2, and H3 receptors
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Histamine is a transmitter that activates the four receptors H1R to H4R. The H3R is found in the nervous system as an autoreceptor and heteroreceptor, and controls the release of neurotransmitters, making it a potential drug target for neuropsychiatric conditions. We have previously reported that the 1-(2,3-dihydro-1-benzofuran-2-yl)methylpiperazines (LINS01 compounds) have the selectivity for the H3R over the H4R. Here, we describe their pharmacological properties at the human H1R and H2R in parallel with the H3R, thus providing a full analysis of these compounds as histamine receptor ligands through reporter gene assays. Eight of the nine LINS01 compounds inhibited H3R-induced histamine responses, but no inhibition of H2R-induced responses was seen. Three compounds were weakly able to inhibit H1R-induced responses. No agonist responses were seen to any of the compounds at any receptor. SAR analysis shows that the N-methyl group improves H3R affinity while the N-phenyl group is detrimental. The methoxy derivative, LINS01009, had the highest affinity.
- Corrêa, Michelle Fidelis,Barbosa, álefe Jhonatas Ramos,Fernandes, Gustavo Ariel Borges,Baker, Jillian G.,Fernandes, Jo?o Paulo dos Santos
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- Reduction of C,O-chelated organotin(IV) dichlorides and dihydrides leading to protected polystannanes
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A series of aryloxy organotin compounds Ph3Sn(CH2)3OC6H4R (5: R = H; 6: R = Ph; 7: R = OCH3, 8: R = CF3), Ph2ClSn(CH2)3OC6H4R (9: R = H; 10: R = Ph) and PhCl2Sn(CH2)3OC6H4R (12: R = H; 13: R = Ph) have been synthesized and characterised by NMR (1H, 13C, 119Sn) spectroscopy. X-ray structure determinations of 9, 10, 12 and 13 reveal a distorted trigonal bipyramidal geometry at Sn with Cl trans to the datively bonded O whereas 8 possesses tetrahedral geometry and a Sn? dative interaction is absent. Triorganotin hydrides Ph2HSn(CH2)3OC6H4R (14: RH; 15: RPh) and diorganotin dihydrides PhH2Sn(CH2)3OC6H4R (16: RH; 17: RPh) were prepared by reduction of the corresponding dihalides with LiAlH4. Catalytic dehydrocoupling of dihydrides 16 or 17 with a late transition metal catalyst afforded asymmetrical hypercoordinated polystannanes [PhSn(CH2)3OC6H4R]n (18: RH; 19: RPh) with relatively high molecular weights (Mw 1.3 104 e 2.5 105 Da) and narrow polydispersities (PDI's 1.3e3.3). NMR and UVeVis spectroscopy studies indicate that the new polymers display dramatically improved light stability, but remain sensitive to moisture.
- Khan, Aman,Komejan, Sarah,Patel, Aagam,Lombardi, Christopher,Lough, Alan J.,Foucher, Daniel A.
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- Differentiating allylic and vinylic leaving groups for Pd catalysis. The use of vinyl iodide to facilitate room temperature activation of a vinyl C-X bond in the presence of allyl carbonate
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Ionization of allylic, stabilized leaving groups by Pd catalysis is a very facile process at or below room temperature, whereas oxidative addition of many vinyl or aryl C-X bonds requires heating. There are only a handful of examples in the literature where a vinyl leaving group can be activated in a competitive fashion in the presence of a suitable allylic one. In this report a series of polyfunctional olefin building blocks have been constructed that allow vinyl halides to be selectively and routinely activated in the presence of highly active allylic leaving groups. This differentiation is dependent solely on the bond strengths of the leaving groups involved and shows no temperature dependence to differentiate the two processes.
- Organ, Michael G.,Arvanitis, Elena A.,Villani, Anita,Majkut, Yvette,Hynes, Stephen
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- Palladium-catalyzed anti-Markovnikov oxidative acetalization of activated olefins with iron(iii) sulphate as the reoxidant
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This paper discloses the efficient palladium-catalyzed anti-Markovnikov oxidative acetalization of activated terminal olefins with iron(iii) sulfate as the reoxidant. This methodology requires mild reaction conditions and shows high regioselectivity toward anti-Markovnikov products and compatibility with a wide range of functional groups. Iron(iii) sulphate was the sole reoxidant used in this method. Various olefins like vinylarenes, aryl-allylethers, aryl or benzyl acrylates and homoallylic alcohols all reacted well providing anti-Markovnikov acetals, some of which represent orthogonally functionalized 1,3- and 1,4-dioxygenated compounds.
- Fernandes, Rodney A.,Kumar, Praveen,Yadav, Sandhya S.
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p. 427 - 443
(2022/01/20)
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- Nickel-catalyzed deallylation of aryl allyl ethers with hydrosilanes
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An efficient and mild catalytic deallylation method of aryl allyl ethers is developed, with commercially available Ni(COD)2 as catalyst precursor, simple substituted bipyridine as ligand and air-stable hydrosilanes. The process is compatible with a variety of functional groups and the desired phenol products can be obtained with excellent yields and selectivity. Besides, by detection or isolation of key intermediates, mechanism studies confirm that the deallylation undergoes η3-allylnickel intermediate pathway.
- Ding, Guangni,Fan, Sijie,Wang, Jingyang,Wang, Yu,Wu, Xiaoyu,Xie, Xiaomin,Yang, Liqun,Zhang, Zhaoguo
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supporting information
(2021/09/28)
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- Allylphenols as a new class of human 15-lipoxygenase-1 inhibitors
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In this study, a series of mono- and diallylphenol derivative were designed, synthesized, and evaluated as potential human 15-lipoxygenase-1 (15-hLOX-1) inhibitors. Radical scavenging potency of the synthetic allylphenol derivatives was assessed and the results were in accordance with lipoxygenase (LOX) inhibition potency. It was found that the electronic natures of allyl moiety and para substituents play the main role in radical scavenging activity and subsequently LOX inhibition potency of the synthetic inhibitors. Among the synthetic compounds, 2,6-diallyl-4-(hexyloxy)phenol (42) and 2,6-diallyl-4-aminophenol (47) showed the best results for LOX inhibition (IC50 = 0.88 and 0.80 μM, respectively).
- Alavi, Seyed Jamal,Seyedi, Seyed Mohammad,Saberi, Satar,Safdari, Hadi,Eshghi, Hossein,Sadeghian, Hamid
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p. 259 - 266
(2020/10/12)
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- Novel potent (dihydro)benzofuranyl piperazines as human histamine receptor ligands – Functional characterization and modeling studies on H3 and H4 receptors
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Histamine acts through four different receptors (H1R-H4R), the H3R and H4R being the most explored in the last years as drug targets. The H3R is a potential target to treat narcolepsy, Parkinson's disease, epilepsy, schizophrenia and several other CNS-related conditions, while H4R blockade leads to anti-inflammatory and immunomodulatory effects. Our group has been exploring the dihydrobenzofuranyl-piperazines (LINS01 series) as human H3R/H4R ligands as potential drug candidates. In the present study, a set of 12 compounds were synthesized from adequate (dihydro)benzofuran synthons through simple reactions with corresponding piperazines, giving moderate to high yields. Four compounds (1b, 1f, 1g and 1h) showed high hH3R affinity (pKi > 7), compound 1h being the most potent (pKi 8.4), and compound 1f showed the best efficiency (pKi 8.2, LE 0.53, LLE 5.85). BRET-based assays monitoring Gαi activity indicated that the compounds are potent antagonists. Only one compound (2c, pKi 7.1) presented high affinity for hH4R. In contrast to what was observed for hH3R, it showed partial agonist activity. Docking experiments indicated that bulky substituents occupy a hydrophobic pocket in hH3R, while the N-allyl group forms favorable interactions with hydrophobic residues in the TM2, 3 and 7, increasing the selectivity towards hH3R. Additionally, the importance of the indole NH in the interaction with Glu5.46 from hH4R was confirmed by the modeling results, explaining the affinity and agonistic activity of compound 2c. The data reported in this work represent important findings for the rational design of future compounds for hH3R and hH4R.
- Corrêa, Michelle F.,Balico-Silva, André L.,Kiss, Dóra J.,Fernandes, Gustavo A.B.,Maraschin, Jhonatan C.,Parreiras-e-Silva, Lucas T.,Varela, Marina T.,Sim?es, Sarah C.,Bouvier, Michel,Keser?, Gy?rgy M.,Costa-Neto, Claudio M.,Fernandes, Jo?o Paulo S.
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- TRICYCLIC FURAN-SUBSTITUTED PIPERIDINEDIONE COMPOUND
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Disclosed are a series of tricyclic furan-substituted piperidinedione compounds and an application thereof in preparing a drug for treating a disease related to CRBN protein. In particular, disclosed is a derivative compound represented by formula (I) or a pharmaceutically acceptable salt thereof.
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Paragraph 0132-0133
(2021/07/17)
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- TRICYCLIC SUBSTITUTED PIPERIDINE DIONE COMPOUND
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Disclosed is a series of tricyclic substituted piperidine dione compounds, and applications thereof in the preparation of medicines for treating diseases related to CRBN protein; specifically disclosed are the derivative compound represented by formula (I) or a pharmaceutically acceptable salt thereof.
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Paragraph 0107-0108
(2021/07/17)
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- Enantioselective synthesis of 1-aminoindene derivativesviaasymmetric Br?nsted acid catalysis
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We describe a catalytic asymmetric iminium ion cyclization reaction of simple 2-alkenylbenzaldimines using a BINOL-derived chiralN-triflyl phosphoramide. The corresponding 1-aminoindenes and tetracyclic 1-aminoindanes are formed in good yields and high enantioselectivities. Further, the chemical utility of the obtained enantiopure 1-aminoindene is demonstrated for the asymmetric synthesis of (S)-rasagiline.
- Ding, Du,Jiang, Hua-Jie,Wang, Tao,Wu, Xiang,Zhang, Ying,Zhao, Li-Ping
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supporting information
p. 9680 - 9683
(2021/09/30)
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- Novel potent vasodilating agents: Evaluation of the activity and potency of LINS01005 and derivatives in rat aorta
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Cardiovascular diseases (CVDs) present high prevalence rates in the current world. It is estimated that approximately one-third of the global deaths are related to CVDs, and thus there is still a need for novel drugs to treat these disorders. We serendipitously discovered that LINS01005 (5a) is a potent vasodilating agent in rat aorta, and therefore a set of analogues were evaluated for the vasodilating potency in Wistar and SHR rat thoracic aorta precontracted with norepinephrine, with endothelium intact (E+) or denuded (E–) aortic rings. Compounds 5a and 5b were the most potent, showing submicromolar potency for endothelium intact vessels (EC50 853 and 941 nM, respectively) and micromolar values for E– vessels (EC50 2.4 and 7.1 μM, respectively). These compounds were indeed significantly more potent vasodilating agents in SHR-derived aortic rings (p 50 2.4 nM (E+) 9.0 nM (E–)] and 5b [EC50 20 nM (E+) 2.1 μM (E–)]. SAR analysis though PCA and HCA were performed, suggesting that N-phenylpiperazine is essential to the activity, while increasing volume in the substituted aromatic moiety is detrimental to the potency. This is the first report of the vasodilating properties of such compounds, and studies regarding the mechanism of action are in progress in our group.
- Ginoza, Milton,Fernandes, Gustavo A.B.,Corrêa, Michelle F.,Fernandes, Jo?o Paulo S.
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- Chemoselective Epoxidation of Allyloxybenzene by Hydrogen Peroxide Over MFI-Type Titanosilicate
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The chemoselective synthesis of 2-(phenoxymethyl)oxirane from allyloxybenzene is achieved with over 90 % yield in a sustainable reaction system using titanium-substituted silicalite-1 (TS-1) as a catalyst, hydrogen peroxide (H2O2) as an oxidant, and a mixture of MeOH/MeCN as a solvent at 40 °C. No acid-catalyzed side reactions prompted by the Lewis acidity of the Ti active site in TS-1 are observed. The TS-1 catalyst can also promote the formation of oxiranes from various p-substituted allyloxybenzenes in good yields. The reaction mechanism is investigated through the reaction with other allyloxy compounds. The results, which are supported by DFT calculations, indicate that an active species of Ti peroxides formed from the reaction of TS-1 with H2O2 selectively oxidizes the allyloxybenzene to 2-(phenoxymethyl)oxirane.
- Fujitani, Tadahiro,Hong, Dachao,Ito, Satoru,Ji, Xinyi,Kon, Yoshihiro,Nakashima, Takuya,Osuga, Ryota,Sato, Kazuhiko,Yokoi, Toshiyuki
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supporting information
(2020/04/15)
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- Enantioselective Construction of Si-Stereogenic Center via Rhodium-Catalyzed Intermolecular Hydrosilylation of Alkene
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Catalytic, enantioselective synthesis of stereogenic silicon compounds remains a challenge. Herein, we report a rhodium-catalyzed regio- and enantio-selective intermolecular hydrosilylation of alkene with prochiral dihydrosilane. This new method features a simple catalytic system, mild reaction conditions and a wide functional group tolerance.
- He, Tao,Liu, Li-Chuan,Ma, Wen-Peng,Li, Bin,Zhang, Qing-Wei,He, Wei
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supporting information
p. 17011 - 17015
(2020/11/30)
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- Investigating the microwave-accelerated Claisen rearrangement of allyl aryl ethers: Scope of the catalysts, solvents, temperatures, and substrates
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The microwave-accelerated Claisen rearrangement of allyl aryl ethers was investigated, in order to gain insight into the scope of the catalysts, solvents, temperatures, and substrates. Among the catalysts examined, phosphomolybdic acid (PMA) was found to greatly accelerate the reaction in NMP, at temperatures ranging from 220 to 300 °C. This method was found to be useful for preparing several intermediates previously reported in the literature using precious metal catalysts such as Au(I), Ag(I), and Pt(II). Additionally, substrates bearing bromo and nitro groups on the aryl portion required careful tailoring of the reaction conditions to avoid complex product profiles.
- Hui, Zi,Jiang, Songwei,Qi, Xiang,Ye, Xiang-Yang,Xie, Tian
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supporting information
(2020/05/18)
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- Direct oxidative isoperfluoropropylation of terminal alkenes: Via hexafluoropropylene (HFP) and silver fluoride
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A copper-mediated oxidative isoperfluoropropylation of unactivated terminal alkenes with commercially available hexafluoropropylene (HFP) has been developed. With operational simplicity of the procedure and broad substrate applicability, this strategy pro
- Wang, Xiaojun,Wu, Yongming
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supporting information
p. 1877 - 1880
(2018/02/23)
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- A mild copper catalyzed method for the selective deprotection of aryl allyl ethers
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Copper boryl reagents enable the selective cleavage of aryl allyl ethers to the corresponding phenols in good to moderate yields.
- Hemming, David S.,Talbot, Eric P.,Steel, Patrick G.
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supporting information
p. 17 - 20
(2016/12/23)
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- Visible-light-induced thiotrifluoromethylation of terminal alkenes with sodium triflinate and benzenesulfonothioates
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An unconventional reductive quenching cycle was developed to realize the visible-light-induced thiotrifluoromethylation of terminal alkenes. CF3SO2Na was used as an easy to handle CF3 radical source to afford the desired products in moderate to good yields. Mild reaction conditions and a broad substrate scope feature in this transformation.
- Kong, Weiguang,An, Hejun,Song, Qiuling
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supporting information
p. 8968 - 8971
(2017/08/15)
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- Regioselective Alkoxycarbonylation of Allyl Phenyl Ethers Catalyzed by Pd/dppb under Syngas Conditions
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A simple and regioselective synthesis of phenoxy esters and phenylthio esters is reported. The products are obtained by selective alkoxycarbonylation catalyzed by Pd2(dba)3, 1,4-bis(diphenylphisphino)butane (dppb), and syngas (CO/H2) in chloroform/alcohol. This methodology affords bifunctional products in good yield with excellent n-selectivity and without the need to use additives.
- Amézquita-Valencia, Manuel,Alper, Howard
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p. 3860 - 3867
(2016/05/24)
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- Enantioselective synthesis of putative lipiarmycin aglycon related to fidaxomicin/tiacumicin B
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An enantioselective synthesis of a putative lipiarmycin aglycon was accomplished and features: 1) Brown's enantioselective alkoxyallylboration and allylation of aldehydes, 2) chain elongation by iterative Horner-Wadsworth-Emmons olefination, 3) Evans' aldol reaction and 4) an enediene ring-closing metathesis. A neighboring-group-assisted chemoselective reductive desilylation was uncovered in this study and was instrumental to the realization of the present synthesis.
- Erb, William,Grassot, Jean-Marie,Linder, David,Neuville, Luc,Zhu, Jieping
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supporting information
p. 1929 - 1932
(2015/02/19)
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- Synthesis and some features of phase behavior of chiral p-alkoxyphenyl glycerol ethers
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A series of (S)-3-(4-alkoxyphenoxy)propane-1,2-diols was prepared with the enantiomeric excess 86-92% by Sharpless asymmetric dihydroxylation of 1-alkoxy-4-allyloxybenzenes with an AD-mix-β mixture. R-Enantiomers with enantiomeric excess 97-99% and racemic samples were obtained by reaction of sodium p-substituted phenolates with (R)- and rac-3-chloropropane-1,2-diol. The phase behavior of racemates and scalemates in the produced homolog series of glycerol aryl ethers with hydrocarbon substituents of various length was examined by means of thermomicroscopy. The higher memberes of the homolog series of both racemic and scalemic diols undergo at heating an enantiotropic phase transition to a smectic liquid crystal phase.
- Fayzullin,Antonovich,Zakharychev,Bredikhina,Kurenkov,Bredikhin
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p. 202 - 209
(2015/04/14)
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- Photocatalytic synthesis of dihydrobenzofurans by oxidative [3+2] cycloaddition of phenols
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We report a protocol for oxidative [3+2] cycloadditions of phenols and alkenes applicable to the modular synthesis of a large family of dihydrobenzofuran natural products. Visible-light-activated transition metal photocatalysis enables the use of ammonium persulfate as an easily handled benign terminal oxidant. The broad range of organic substrates that are readily oxidized by photoredox catalysis suggests that this strategy may be applicable to a variety of useful oxidative transformations.
- Blum, Travis R.,Zhu, Ye,Nordeen, Sarah A.,Yoon, Tehshik P.
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supporting information
p. 11056 - 11059
(2015/03/30)
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- Asymmetric Pd-Catalyzed Alkene Carboamination Reactions for the Synthesis of 2-Aminoindane Derivatives
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A new type of Pd-catalyzed alkene carboamination reaction that provides direct access to enantioenriched 2-aminoindanes from 2-allylphenyltriflate derivatives and aliphatic amines is described. A catalyst generated in situ from Pd(OAc)2 and (S)-tert-butylPHOX provides the functionalized carbocycles in good yield with up to >99:1 er. The transformations occur via a key anti-aminopalladation that involves intermolecular attack of an amine nucleophile on an arylpalladium alkene complex.
- White, Derick R.,Hutt, Johnathon T.,Wolfe, John P.
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supporting information
p. 11246 - 11249
(2015/09/21)
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- New synthesis of artepillin C, a prenylated phenol, utilizing lipase-catalyzed regioselective deacetylation as the key step
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We have synthesized artepillin C, a diprenylated p-hydroxycinnamate originally isolated from Brazilian propolis and exhibiting antioxidant and antitumor activities, from 2,6-diallylphenol. Replacement of the terminal vinyl with 2,2-dimethylvinyl group by olefin cross-metathesis and subsequent transformation yielded 2,6-diprenyl-1,4-hydroquinone diacetate. Candida antarctica lipase B-catalyzed deacetylation in 2-propanol regioselectively removed the less hindered acetyl group to give 2,6-diprenyl-1,4-hydroquinone 1-monoacetate. After triflation of the liberated 4-hydroxy group, a three-carbon side chain was introduced by palladium-mediated alkenylation with methyl acrylate. Final hydrolysis of the esters furnished artepillin C.
- Yashiro, Kazuki,Hanaya, Kengo,Shoji, Mitsuru,Sugai, Takeshi
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p. 1926 - 1930
(2015/11/24)
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- Enantioselective Hydroformylation of 1-Alkenes with Commercial Ph-BPE Ligand
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A rhodium complex, in conjunction with commercially available Ph-BPE ligand, catalyzes the branch-selective asymmetric hydroformylation of 1-alkenes and rapidly generates α-chiral aldehydes. A wide range of terminal olefins including 1-dodecene were examined, and all delivered high enantioselectivity (up to 98:2 er) as well as good branch:linear ratios (up to 15:1). (Chemical Equation Presented).
- Yu, Zhiyong,Eno, Meredith S.,Annis, Alexandra H.,Morken, James P.
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supporting information
p. 3264 - 3267
(2015/07/15)
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- Novel Ether Linked Compounds and Improved Treatments for Cardiac and Cardiovascular Disease
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A compound of Formula (I), and its pharmaceutically acceptable salt or salts and physiologically hydrolysable derivatives in free form or salt form: wherein R1 is independently selected from F, Cl, Br, CN, NH2, OH, CHO, COOH, oxo, C1-4alkyl, C1-4alkoxy, CONH2 (optionally mono- or di-substituted by C1-4alkyl) and SO2NH2, R2 is independently selected from C1-6allkyl substituted by R3 wherein the C1-6alkyl chain optionally comprises one or two heteroatoms select from O; R3 is selected from aryl, C3-6cycloalkyl, C3-6heterocyclyl and C3-6heteroaryl, wherein the heterocyclyl and heteroaryl rings are nitrogen containing; and wherein R3 is optonally substituted by one or more groups selected from R1; n1 is zero or an integer from 1 to 2; n2 is an integer from 1 to 2; and the sum of n1 and 2 is less than or equal to 2; R5 is selected from any group defined for R1 and R2; R6a and R6b are independently selected from H or C1-4alkyl; R7 is independently selected from F, Cl, Br, CN, NH2, OH, CHO, COOH, oxo, C1-4alkyl, C1-4alkoxy, CONH2 (optionally mono- or di-substituted by C1-4alkyl) and SO2NH2, Q1, Q2 and Q3 are independently selected from H or any group defined for R1 and R2; or Q1 and Q2 or Q2 and Q3 together form a C5-6heteroaryl or C5-6heterocylclic ring; optionally containing one or two heteroatoms selected from N and O optionally substituted by any group selected from R5; Z is selected from linear C2-3 alkylene; X3 is O; X4 is selected from aryl, a 9-10 membered heteroaryl ring or a 9-10 membered heterocyclic ring, wherein the heteroaryl and heterocyclic rings contain one or more heteroatoms selected from N, and optionally additionally O, and wherein X4 is optionally substituted by one or two oxo moieties and is optionally substituted by one or more groups selected from R7; with the proviso that (i) when X4 is phenyl then Q1 and Q2 or Q2 and Q3—together form an optionally substituted heteroaryl or heterocylclic ring as defined above; and (ii) when Q1, Q2 and Q3 are independently selected from H or any group defined for R1 and R2 then X4 is not phenyl except when R2 is C1-5alkyl substituted by R3 wherein R3 is C3-6heterocyclyl as defined above, their preparation and novel intermediates, compositions thereof and their use in the prevention or treatment of cardiac and cardiovascular disease and methods for the treatment thereof.
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(2014/04/17)
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- PdI2-catalyzed regioselective cyclocarbonylation of 2-allyl phenols to dihydrocoumarins
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A simple, efficient, and regioselective synthesis of 3-methyl-3,4-dihydrocoumarins is reported. The reaction of 2-allyl phenols with synthesis gas was catalyzed by PdI2, and 1,3,5,7-tetramethyl-6-phenyl-2,4,8-trioxa-6-phosphaadamantane (L1) and 1,3,5,7-tetramethyl-6-tetradecyl-2,4,8-trioxa-6-phosphaadamantane (L2) were effective as ligands, affording good product selectivity in all cases.
- Amzquita-Valencia, Manuel,Alper, Howard
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supporting information
p. 5827 - 5829
(2015/01/08)
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- An efficient palladium-catalyzed synthesis of cinnamyl ethers from aromatic halides, phenols, and allylic chloride
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A one-pot, two-step catalytic protocol for the preparation of cinnamyl ethers from simple and readily available aryl halides, phenols and allyl chloride is reported for the first time. This simple and highly efficient palladium nanoparticles catalytic system shows good regio- and stereoselectivities and affords the desired products in good to high yields (49-85%) from aryl iodides. Furthermore, less reactive aryl bromides can also give the cinnamyl ethers in moderate yields (24-72%).
- Wang, Wei,Zhou, Rong,Jiang, Zhi-Jie,Wang, Kun,Fu, Hai-Yan,Zheng, Xue-Li,Chen, Hua,Li, Rui-Xiang
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supporting information
p. 616 - 622
(2014/05/20)
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- Synthesis and antioxidant activity of 5-hydroxycoumarans,c 6-hydroxychromanes and sulfur-containing derivatives on their base
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A synthesis of 5-hydroxycoumarans, 6-hydroxychromanes and their dodecylthiomethyl- substituted derivatives was accomplished based on methylphenols through the intermediate preparation of 2-allyl-4-alkoxyphenols. The sulfur-containing compounds synthesized
- Yagunov,Khol'shin,Kandalintseva,Prosenko
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p. 1395 - 1400
(2014/05/06)
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- NiCl2·6H2O/NaBH4 in methanol: A mild and efficient strategy for chemoselective deallylation/debenzylation of aryl ethers
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Deprotection of allyl/benzyl aryl ethers was achieved chemoselectively. The mild and inexpensive reagent combination of NiCl2·6H 2O/NaBH4 in methanol afforded the products in high yields, within a reaction time of 5-10 min.
- Chouhan, Mangilal,Kumar, Kapil,Sharma, Ratnesh,Grover, Vikas,Nair, Vipin A.
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supporting information
p. 4540 - 4543
(2013/08/23)
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- Enantioselective synthesis of benzofurans and benzoxazines via an olefin cross-metathesis-intramolecular oxo-Michael reaction
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Chiral phosphoric acid and Hoveyda-Grubbs II were found to catalyze an olefin cross-metathesis-intramolecular oxo-Michael cascade reaction of the ortho-allylphenols and enones to provide a variety of benzofuran and benzoxazine derivatives in moderate to good yields and enantioselectivity.
- Zhang, Jun-Wei,Cai, Quan,Gu, Qing,Shi, Xiao-Xin,You, Shu-Li
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supporting information
p. 7750 - 7752
(2013/09/02)
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- Efficient allylation of nucleophiles catalyzed by a bifunctional heterogeneous palladium complex-tertiary amine system
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We demonstrate the synergistic catalysis of a silica-supported diaminopalladium complex and a tertiary amine (SiO2/diamine/Pd/ NEt2) as well as synthetic scope of the Tsuji-Trost reaction of 1,3-dicarbonyls, phenols, and carboxylic acids with allyl carbonate and acetates. The synergistic catalysis of SiO2/diamine/Pd/NEt 2 exhibited wide applicability and high activity for the Tsuji-Trost reaction. For example, the reaction of ethyl 3-oxobutanate with allyl methyl carbonate afforded the allylated product in >99% yield at 70 °C for 5 h. The yield of allylated products was 26% for SiO2/diamine/Pd, without immobilization of the tertiary amine group. In the reaction of 1.0 mmol of ethyl 3-oxobutanate using 0.60 μmol of Pd in SiO2/diamine/Pd/NEt 2, the turnover number (TON) of Pd reached up to 1070 within 24 h. Phenols with electron-withdrawing groups, such as nitro and chloro groups, on the para position resulted in high product yields. The SiO2/diamine/ Pd/NEt2 catalyst was reusable at least 4 times without appreciable loss of its activity and selectivity in the reaction of p-chlorophenol. Copyright
- Noda, Hiroto,Motokura, Ken,Miyaji, Akimitsu,Baba, Toshihide
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p. 973 - 980
(2013/05/08)
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- NOVEL ETHER LINKED COMPOUNDS AND IMPROVED TREATMENTS FOR CARDIAC AND CARDIOVASCULAR DISEASE
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A compound of Formula (I), and its pharmaceutically acceptable salt or salts and physiologically hydrolysable derivatives in free form or salt form: wherein R1 is independently selected from F, CI, Br, CN, NH2, OH, CHO, COOH, oxo, C1-4alkyl, C1-4alkoxy, CONH2 (optionally mono- or di-substituted by C1-4alkyl) and SO2NH2, R2 is independently selected from C1-6allkyl substituted by R3 wherein the C1-6alkyl chain optionally comprises one or two heteroatoms select from O; R3 is selected from aryl, C3-6cycloalkyl, C3-6heterocyclyl and C3-6heteroaryl, wherein the heterocyclyl and heteroaryl rings are nitrogen containing; and wherein R3 is optonally substituted by one or more groups selected from R1; n1 is zero or an integer from 1 to 2; n2 is an integer from 1 to 2; and the sum of n1 and 2 is less than or equal to 2; R5 is selected from any group defined for R1 and R2; R6a and R6b are independently selected from H or C1-4alkyl; R7 is independently selected from F, CI, Br, CN, NH2, OH, CHO, COOH, oxo, C1-4alkyl, C1-4alkoxy, CONH2 (optionally mono- or di-substituted by C1-4alkyl) and SO2NH2, Q1, Q2 and Q3 are independently selected from H or any group defined for R1 and R2; or Q1 and Q2 or Q2 and Q3 together form a C5-6heteroaryl or C5-6heterocylclic ring; optionally containing one or two heteroatoms selected from N and O optionally substituted by any group selected from R5; Z is selected from linear C2-3 alkylene; X3 is O; X4 is selected from aryl, a 9-10 membered heteroaryl ring or a 9-10 membered heterocyclic ring, wherein the heteroaryl and heterocyclic rings contain one or more heteroatoms selected from N, and optionally additionally O, and wherein X4 is optionally substituted by one or two oxo moieties and is optionally substituted by one or more groups selected from R7; with the proviso that: (i) when X4 is phenyl then Q1 and Q2 or Q2 and Q3-together form an optionally substituted heteroaryl or heterocylclic ring as defined above; and (ii) when Q1, Q2 and Q3 are independently selected from H or any group defined for R1 and R2 then X4 is not phenyl except when R2 is C1-5alkyl substituted by R3 wherein R3 is C3-6heterocyclyl as defined above.
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Page/Page column 52-53
(2012/08/27)
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- Electrochemically supported deoxygenation of epoxides into alkenes in aqueous solution
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An efficient synthesis of alkenes from epoxides in a mixture of saturated aqueous NH4Br and tetrahydrofuran (8:1) has been developed in an undivided cell fitted with a pair of zinc electrodes, and it is proposed that the reaction is mediated by Zn(0) with a hierarchically organized nanostructure.
- Huang, Jing-Mei,Lin, Zhi-Quan,Chen, Dong-Song
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supporting information; experimental part
p. 22 - 25
(2012/03/22)
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- Design, synthesis and cytotoxic activities of novel hybrid compounds between dihydrobenzofuran and imidazole
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A series of novel hybrid compounds between dihydrobenzofuran and imidazole has been prepared and evaluated in vitro against a panel of human tumor cell lines. The results suggest that substitution of the imidazolyl-1-position with an electron-donating dihydrobenzofuran, and the imidazolyl-3-position with a naphthylacyl or electron-rich phenacyl group, were vital for modulating cytotoxic activity.
- Chen, Wen,Yang, Xiao-Dong,Li, Yan,Yang, Li-Juan,Wang, Xue-Quan,Zhang, Gao-Lan,Zhang, Hong-Bin
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supporting information; experimental part
p. 4250 - 4255
(2011/07/29)
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- Synthesis and SAR comparative studies of 2-allyl-4-methoxy-1-alkoxybenzenes as 15-lipoxygenase inhibitors
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A group of 2-alkoxy-5-methoxyallylbenzene were designed, synthesised and evaluated as potential inhibitors of the soybean 15-lipoxygenase (SLO) on the basis of the eugenol and esteragol structures. Compound 4d showed the best half maximal inhibitory concentration (IC50) for SLO inhibition (IC 50=5.9±0.6 μM). All the compounds were docked in the SLO active site retrieved from the Research Collaboratory for Structural Bioinformatics (RCSB) Protein Data Bank (PDB entry: 1IK3) and showed that the allyl group of the synthetic compounds similar to the linoleic acid double bond, were oriented toward the Fe3+-OH moiety in the active site of the enzyme and this conformation was especially fixed by the hydrophobic interaction of the 2-alkoxy group with Leu515, Trp519, Val 566 and Ile572. It was concluded that the molecular volume and shape of the alkoxy moiety was a major factor in the inhibitory potency variation of the synthetic compounds.
- Sadeghian, Hamid,Seyedi, Seyed Mohammad,Attaran, Neda,Jabbari, Atena,Jafari, Zeinab
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experimental part
p. 238 - 244
(2011/11/12)
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- METHODS AND COMPOSITIONS FOR CONTROL OF CABBAGE LOOPER, Trichoplusia ni
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The invention provides in part dialkoxybenzene compounds for controlling infestation by a Trichoplusia ni, and methods thereof. The compounds include a compound of Formula I: where R1 may be methyl, ethyl, propyl, n-butyl, isopentyl(3-methylbutyl) or allyl; R2 may be at positions 2, 3 or 4 and may be H, methyl, ethyl, propyl, n-butyl, isopentyl(3-methylbutyl) or allyl; and R3 may be optionally present at positions 2, 3 and 4, and is allyl; except that when R2 is at position 2, R3 if present is at position 3, and when R2 is at position 3, R3 if present is at positions 2 or 4, and when R2 is at position 4, R3 if present is at position 2, and when R2 is at position 4 and R3, if present, has reacted with an OH group at position 1 in a Markovnikov sense, then R3 becomes R4, a dihydrofuran.
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Page/Page column 22
(2010/07/04)
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- Dialkoxybenzene and dialkoxyallylbenzene feeding and oviposition deterrents against the cabbage looper, trichoplusia ni: Potential insect behavior control agents
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The antifeedant, oviposition deterrent, and toxic effects of individual dialkoxybenzene compounds/sets and of hydroxy- or alkoxy-substituted allylbenzenes, obtained through Claisen rearrangement of substituted allyloxybenzenes, were assessed against the cabbage looper, Trichoplusia ni, in laboratory bioassays. Most of the compounds/sets strongly deterred larval feeding, with some exhibiting mild toxic and oviposition deterrent effects as well. Some of the compounds/sets were more active than the commercial insect repellent, DEET (N,N-diethyl-m-toluamide), as both feeding and oviposition deterrents against the cabbage looper. On the basis of the obtained oviposition data a general hypothesis was proposed regarding the oviposition sites: one binding mode with the alkyl and allyl groups on the same side of the benzene ring resulted in deterrence, the other with alkyl and allyl groups on opposite sides of the benzene ring resulted in stimulation. The results suggest some structure-activity relationships useful in improving the efficacy of the compounds and designing new, nontoxic insect control agents for agriculture.
- Akhtar, Yasmin,Yu, Yang,Isman, Murray B.,Plettner, Erika
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p. 4983 - 4991
(2011/08/06)
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- Use of diethoxymethane as a solvent for phase transfer-catalyzed O -alkylation of phenols
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The effectiveness of diethoxymethane (DEM) as a solvent for O-alkylation of a variety of phenols under phase transfer conditions has been examined and evaluated. The reaction between 4-methoxy phenol and benzyl chloride was selected to compare reaction rates in various solvents and the efficiency of various PTCs. This reaction was further studied to develop a commercially amenable process complete with recycle streams and efficient product isolation. DEM is a good solvent for these types of phase transfer-catalyzed reactions and can be considered as an alternative solvent for dichloromethane and toluene.
- Coleman, M. Todd,Leblanc, Gabriel
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experimental part
p. 732 - 736
(2011/07/07)
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- Regioselective iron-catalyzed decarboxylative allylic etherification
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[Chemical Equation Presented] An anionic iron complex catalyzes the decarboxylative allylation of phenols to form allylic ethers in high yield. The allylation is regioselective rather than regiospecific. This suggests that the allylation proceeds through π-allyl iron intermediates in contrast to related allylations of carbon nucleophiles that have been proposed to proceed via π-allyl complexes. Ultimately, iron catalysts have the potential to replace more expensive palladium catalysts that are typically utilized for decarboxylative couplings.
- Trivedi, Rushi,Tunge, Jon A.
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supporting information; experimental part
p. 5650 - 5652
(2010/02/28)
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- Stereoselective construction of substituted chromans by palladium-catalyzed cyclization of propargylic carbonates with 2-(2-Hydroxyphenyl)acetates
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Highly substituted chromans have been constructed In a highly stereoselective manner by a palladium-catalyzed reaction of propargylic carbonates with 2-(2-hydroxyphenyl)acetates. Enantioselective reactions also successfully proceeded to give the optically active chromans with high enantioselectivity.
- Yoshida, Masahiro,Higuchi, Mariko,Shishido, Kozo
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supporting information; experimental part
p. 4752 - 4755
(2009/12/09)
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- Synthesis of 6,6-bisbenzannulated spiroketals related to the rubromycins using a double intramolecular hetero-Michael addition (DIHMA)
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The synthesis of a series of 6,6-bisbenzannulated spiroketals using a novel microwave-assisted DIHMA approach is reported. Coupling of an aryl acetylene and an aryl aldehyde via acetylide anion addition resulted in the formation of an alkynol which was followed by oxidation to the desired ynone. Spirocyclization using the DIHMA protocol afforded the desired bisbenzannulated spiroketal in good yield.
- Choi, Peter J.,Rathwell, Dominea C.K.,Brimble, Margaret A.
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scheme or table
p. 3245 - 3248
(2009/08/17)
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- Natural tanshinone-like heterocyclic-fused ortho-quinones from regioselective Diels-Alder reaction: Synthesis and cytotoxicity evaluation
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A series of new natural tanshinone-like oxoheterocyclic-fused ortho-quinone derivatives were synthesized from readily available benzofuranol and N-substituted dienes via IBX oxidation-cycloaddition-aromatization procedure. The regiospecific Diels-Alder cycloaddition reactions of N-dienes were achieved efficiently with a variety of dienophiles. It is found that the amide moiety in the molecular could be preserved or eliminated by control of the aromatization conditions. Selected oxoheterocyclic-fused ortho-quinones as well as several thioheterocyclic-fused ortho-quinones we obtained before were evaluated for their cytotoxicities on different cancer cell lines and the Structure-Activity Relationship (SAR) was discussed.
- Shen, Yu-Dong,Tian, Yuan-Xin,Bu, Xian-Zhang,Gu, Lian-Quan
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scheme or table
p. 3915 - 3921
(2009/12/04)
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- General, mild, and intermolecular Ullmann-type synthesis of diaryl and alkyl aryl ethers catalyzed by diol-copper(I) complex
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(Chemical Equation Presented) A wide range of diaryl ethers and alkyl aryl ethers are synthesized through intermolecular C(aryl)-O bond formation from the corresponding aryl iodides/aryl bromides and phenols/alcohols through Ullmann-type coupling reaction in the presence of a catalytic amount of easily available (±)-diol L3-CuI complex under very mild reaction conditions. Less reactive aryl bromides can also be used for O-arylation of phenols under the same reaction conditions without increasing the reaction temperature, catalyst loading, and time. The catalytic system not only is capable of coupling hindered substrate but also tolerates a broad range of a series of functional groups.
- Naidu, Ajay B.,Jaseer,Sekar, Govindasamy
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supporting information; experimental part
p. 3675 - 3679
(2009/09/26)
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- An efficient intermolecular BINAM-copper(I) catalyzed Ullmann-type coupling of aryl iodides/bromides with aliphatic alcohols
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A wide range of alkyl aryl ethers are synthesized from the corresponding aryl iodides and aliphatic alcohols through Ullmann-type intermolecular coupling reactions in the presence of a catalytic amount of easily available BINAM-CuI complex. Less reactive aryl bromides have also been shown to react with aliphatic alcohols under identical reaction conditions to give good yields of the alkyl aryl ethers without increasing the reaction temperature and time.
- Naidu, Ajay B.,Sekar
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p. 3147 - 3151
(2008/09/20)
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- Synthesis of aromatic spiroacetals related to γ-rubromycin based on a 3H-spiro[1-benzofuran-2,2′-chromane] skeleton
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The synthesis of a series of aromatic 5,6-benzannelated and naphthyl-benzannelated spiroacetals related to the spiroacetal unit present in the quinonoid antibiotic γ-rubromycin is reported. The key steps include the use of Sonogashira coupling to construct an aryl acetylene that is coupled to an aryl aldehyde forming a propargyl alcohol intermediate. Hydrogenation of the resultant alkynol followed by oxidation produces a masked dihydroxyketone that upon treatment with silica-supported sodium hydrogen sulfate undergoes concomitant deprotection and cyclisation to afford the desired fused aromatic spiroacetal.
- Tsang, Kit Yee,Brimble, Margaret A.
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p. 6015 - 6034
(2008/02/02)
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- Microwave-accelerated Claisen rearrangement in bicyclic imidazolium [b-3C-im][NTf2] ionic liquid
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With microwaves, a chemically stable ionic liquid [b-3C-im][NTf2] recently developed in our laboratory was used as solvent and successfully applied to accelerate Claisen rearrangement reactions at high temperatures. In the presence of Lewis acid MgCl2, these thermal rearrangements could be achieved in similar reaction times but at lower temperature. For the microwaved reactions studied in this work, without scarifying isolated yields, the reaction times were significantly reduced from hours (by conventional heating) to ≤3 min. Our result also demonstrated that [b-3C-im][NTf2] ionic liquid was a useful solvent substitute and could be recycled multiple times for the studied rearrangement reaction at elevated temperatures.
- Lin, Yung-Lun,Cheng, Jen-Yen,Chu, Yen-Ho
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p. 10949 - 10957
(2008/02/13)
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- A facile synthesis of fused aromatic spiroacetals based on the 3,4,3′,4′-tetrahydro-2,2′-spirobis(2H-1-benzopyran) skeleton
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The facile synthesis of a series of aromatic 6,6-spiroacetals based on the parent 3,4,3′,4′-tetrahydro-2,2′-spirobis(2H-1-benzopyran) heterocyclic system is reported. Key steps included the use of a Sonogashira coupling for the synthesis of an aryl acetylene that was coupled to an aryl aldehyde to form a propargyl alcohol intermediate. Hydrogenation of the alkynol followed by oxidation produced a masked dihydroxy ketone that upon treatment with trimethylsilyl bromide underwent deprotection and cyclisation to the fused aromatic spiroacetal.
- Brimble, Margaret A.,Flowers, Christopher L.,Trzoss, Michael,Tsang, Kit Y.
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p. 5883 - 5896
(2007/10/03)
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- Silver-catalyzed asymmetric synthesis of 2,3-dihydrobenzofurans: A new chiral synthesis of pterocarpans
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2,3-Dihydrobenzofurans can be diastereoselectively prepared by condensation of aromatic aldehydes with 2,3-dihydrobenzoxasilepines under the catalysis of Ag1 complexes, and in the presence of a source of fluoride ion. The application of this st
- Jimenez-Gonzalez, Leticia,Garcia-Munoz, Sergio,Alvarez-Corral, Miriam,Munoz-Dorado, Manuel,Rodriguez-Garcia, Ignacio
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p. 8762 - 8769
(2007/10/03)
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