- Allylphenols as a new class of human 15-lipoxygenase-1 inhibitors
-
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.
-
-
- 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.
- -
-
Paragraph 0132; 0134
(2021/07/17)
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- TRICYCLIC SUBSTITUTED PIPERIDINE DIONE COMPOUND
-
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.
- -
-
Paragraph 0107; 0109
(2021/07/17)
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- Investigating the microwave-accelerated Claisen rearrangement of allyl aryl ethers: Scope of the catalysts, solvents, temperatures, and substrates
-
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)
-
- Novel potent vasodilating agents: Evaluation of the activity and potency of LINS01005 and derivatives in rat aorta
-
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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-
- Total Synthesis of Pyrolaside B: Phenol Trimerization through Sequenced Oxidative C?C and C?O Coupling
-
A facile method to oxidatively trimerize phenols using a catalytic aerobic copper system is described. The mechanism of this transformation was probed, yielding insight that enabled cross-coupling trimerizations. With this method, the natural product pyro
- Kozlowski, Marisa C.,Neuhaus, William C.
-
supporting information
p. 7842 - 7847
(2020/04/03)
-
- 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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-
- 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
-
supporting information
p. 268 - 278
(2017/02/05)
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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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p. 90272 - 90280
(2015/11/11)
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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)
-
- 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.
-
supporting information
p. 11246 - 11249
(2015/09/21)
-
- 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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- 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
-
supporting information
p. 5827 - 5829
(2015/01/08)
-
- 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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Page/Page column
(2014/04/17)
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- Synthesis of phosphorus containing medium ring heterocycles by sequential Claisen rearrangement and ring closing metathesis
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An efficient method for the synthesis of novel medium ring phosphorus containing heterocycles starting from phenol derivatives by ruthenium catalyzed ring closing metathesis is described. This work deals with a sequential aromatic Claisen-rearrangement, coupling of an allyl/vinyl phosphonate, and ring closing metathesis reaction. All of these reactions were carried out at ambient temperature to afford the medium-sized phosphorus heterocycles in excellent yields.
- Majumdar,Nandi, Raj Kumar,Ganai, Sintu
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p. 1247 - 1250
(2014/02/14)
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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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- 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
-
supporting information
p. 7750 - 7752
(2013/09/02)
-
- 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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- 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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supporting information; experimental part
p. 1053 - 1063
(2012/07/17)
-
- 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)
-
- 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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- Imidazolium and pyridinium salts - Solvents influencing the rate and direction of the fries, beckmann, and claisen rearrangements
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The Fries, Beckmann, and Claisen rearrangements have been investigated in ionic liquid media. The effect of the structural elements of the latter on the direction of these rearrangements and the product yields has been studied.
- Katkevica,Zicmanis,Mekss
-
scheme or table
p. 158 - 169
(2011/08/05)
-
- Microwave-assisted zeolite catalyzed claisen rearrangement of allyl aryl ethers under solvent-free conditions
-
Claisen rearrangement of allyl aryl ethers has been studied extensively over various zeolites under microwave activation and solvent free conditions at 80°C. Hβ-zeolite is found to be an efficient catalyst for the rearrangement. The reaction gives ω-rearranged product selectively instead of expected further cyclized dihydrobenzofuran derivative.
- Deodhar, Deepak K.,Tipnis, Amol S.,Samant, Shriniwas D
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experimental part
p. 1552 - 1555
(2011/02/23)
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- Agonists and antagonists of antennal responses of gypsy moth (Lymantria dispar) to the pheromone (+)-disparlure and other odorants
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Insects use the sense of smell to guide many behaviors that are important for their survival. The gypsy moth uses a pheromone to bring females and males together over long distances. Male moth antennae are equipped with innervated sensory hairs that selectively respond to pheromone components and other odors. Host plant odors, in particular, are detected by moths and sometimes cause an enhancement of the antennal and behavioral responses of the moths to their pheromone. Inspired by naturally occurring agonists and antagonists of insect pheromone responses, we have screened, by electroantennogram (EAG) recordings, a collection of compound sets and of individual compounds. We have detected interference of some compounds with the EAG responses of male gypsy moth antennae to the pheromone. We describe three activities: (1) short-term inhibition or enhancement of mixed compound + pheromone plumes, (2) long-term inhibition of pure pheromone plumes following a mixed compound + pheromone plume, and (3) inhibition of the recovery phase of mixed compound + pheromone plumes. Long-term inhibition was robust, decayed within 30 s, and correlated with the inhibition of recovery: for both activities clear structure-activity patterns were detected. The commercial repellent N,N-diethyltoluamide (DEET) was included for comparison. The most active and reproducible short-term inhibitor was a mixture of 1 -allyl-2,4-dimethoxybenzene and 2-allyl-1,3-dimethoxybenzene. The most active long-term inhibitors were a set of 1-alkoxy-4-propoxybenzenes, DEET, and 1-ethoxy-4-propoxybenzene. DEET was more specific in the olfactory responses it inhibited than 1-ethoxy-4-propoxybenzene, and DEET did not inhibit recovery, whereas 1-ethoxy-4-propoxybenzene did. Target sites for the three activities are discussed.
- Plettner, Erika,Gries, Regine
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body text
p. 3708 - 3719
(2011/07/30)
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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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scheme or table
p. 4983 - 4991
(2011/08/06)
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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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- Efficient Claisen rearrangement of allyl para-substituted phenyl ethers using microreactors
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A green way to synthesize allyl phenols has been developed. Quantitative yield of 2-allyl-4-methoxyphenol was obtained via a fast Claisen rearrangement in a microreactor system without solvent and work-up.
- Kong, Lingjie,Lin, Qi,Lv, Xiaoming,Yang, Yongtai,Jia, Yu,Zhou, Yaming
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supporting information; experimental part
p. 1108 - 1111
(2010/04/23)
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- Facile aromatic Claisen rearrangement catalysed by tin(IV) chloride
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Allyl aryl ethers undergo facile Claisen rearrangement under mild conditions catalysed by tin(IV) chloride. Georg Thieme Verlag Stuttgart.
- Sarkar, Debayan,Venkateswaran, Ramanathapuram V.
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p. 653 - 654
(2008/12/20)
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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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- UDCaT-5: A novel and efficient solid superacid catalyst for Claisen rearrangement of substituted allyl phenyl ethers
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The Claisen rearrangement of allyl phenyl ethers is a fundamental reaction in organic synthesis with a variety of applications in perfumes, flavors, pharmaceuticals, agrochemicals, polymers, fine chemicals, and intermediate industries. The development of environmentally benign processes using solid acid catalysts is becoming an area of growing interest. It was accomplished in an efficient, economical, environmentally friendly manner and is 100% selective toward alllyl phenols by employing UDCaT-5 as solid acid catalyst. Copyright Taylor & Francis Group, LLC.
- Yadav, Ganapati D.,Lande, Sharad V.
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p. 941 - 946
(2007/10/03)
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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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- 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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p. 2689 - 2691
(2007/10/03)
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- A catalytic antibody against a tocopherol cyclase inhibitor
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The cyclic ammonium cation 5 and its guanidinium analogue 4 areinhibitors of tocopherol cyclase. Monoclonal antibodies were raised against protein conjugates of the haptens 1-3 and screened for catalytic reactions with alkene 8, a short chain analogue of
- Manetsch, Roman,Zheng, Lei,Reymond, Martine T.,Woggon, Wolf-Dietrich,Reymond, Jean-Louis
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p. 2487 - 2506
(2007/10/03)
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- A new synthesis of benzofurans from phenols via claisen rearrangement and ring-closing metathesis
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Based on Claisen rearrangement, the double bond isomerization of O-allyl function together with the formation of O-vinyl function in one pot, and ring-closing metathesis (RCM), various phenols were transformed into various benzofurans in good yields.
- Tsai, Tzu-Wei,Wang, Eng-Chi,Li, Sie-Rong,Chen, Yung-Hua,Lin, Yu-Li,Wang, You-Feng,Huang, Keng-Shiang
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p. 1307 - 1318
(2007/10/03)
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- A hierarchy of aryloxide deprotection by boron tribromide
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Aryl propargyl ethers and esters are cleaved selectively in the presence of aryl methyl ethers and esters by boron tribromide in dichloromethane. Under the same conditions, allyl ethers undergo very rapid Claisen rearrangement, and benzyl ethers are also cleaved more rapidly than propargyl. A mechanism involving intramolecular delivery of bromide to the propargyl terminus is proposed.
- Punna, Sreenivas,Meunier, Stephane,Finn
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p. 2777 - 2779
(2007/10/03)
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- Silanyl phenols and naphthols
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There are described silanyl phenols and naphthols of formula (1a) or (1b), wherein R1 is hydrogen; halogen; hydroxy; C1-C20alkyl; C3-C12cycloalkyl; C1-C20alkoxy; trifluoromethyl; pentafluoroethyl; mono- or di-C1-C5alkylamino; hydroxy-C1-C5alkyl; or phenyl, phenyl-C1C20alkyl, phenoxy, phenyl-C1-C20alkoxy, naphthyl or naphthyl-C1-C20alkyl each unsubstituted or substituted by C1-C5alkyl, C3-C12cycloalkyl, C1-C5alkoxy, C3-C12cycloalkoxy, halogen, oxo, carboxy, carboxy-C1-C7alkyl ester, carboxy-C3-C12cycloalkyl ester, cyano, trifluoromethyl, pentafluoroethyl, amino, N,N-mono- or di-C1-C20alkylamino or by nitro; R2, R3 and R4 are each independently of the others hydrogen; C1-C20alkyl; or C3-C12-Cycloalkyl; R5, R6 and R7 are each independently of the others C1-C20alkyl, C5-C10aryl, C1-C20alkoxy, phenyl-C1-C20alkyl, phenyl-C1-C20alkoxy, C2-C5alkenyl, —O—Si—(C1-C5alkyl)3; or O—Si—(C1-C5alkyl)2-O—Si(C1-C5alkyl)3 and n is 0 or 1. The compounds exhibit a pronounced activity against Gram positive and Gram negative bacteria, and also against yeasts and moulds.
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Page/Page column 7
(2008/06/13)
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- Synthesis of coumarins by ring-closing metathesis using Grubbs' catalyst
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A novel generally applicable synthesis of coumarins from phenolic substrates utilizing ring-closing metathesis is described. This sequence involves O-allylation of phenols followed by ortho-Claisen rearrangement, subsequent based-induced isomerization affording 2-(1-propenyl)phenols, acylation with acryloyl chloride, and finally ring-closing metathesis (RCM) with Grubbs' second generation catalyst.
- Nguyen Van, Tuyen,Debenedetti, Silvia,De Kimpe, Norbert
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p. 4199 - 4201
(2007/10/03)
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- Use of a Sonogashira - Acetylide Coupling Strategy for the Synthesis of the Aromatic Spiroketal Skeleton of γ-Rubromycin
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(Equation presented) The synthesis of the fused aromatic spiroketal core of γ-rubromycin is described via addition of an aryl acetylide fragment to an aryl acetaldehyde fragment. In turn, the aryl acetylene precursor was readily prepared with use of a Sonogashira reaction.
- Tsang, Kit Y.,Brimble, Margaret A.,Bremner, John B.
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p. 4425 - 4427
(2007/10/03)
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- Rhodium- and iridium-catalyzed allylation of electron-rich arenes with allyl tosylate
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The allylation of electron-rich arenes with allyl tosylate proceeded at 0°C in the presence of [Rh(nbd)(CH3CN)2]PF 6. Various oxygenated arenes were allylated with high para-selectivity in almost all cases. Especially in t
- Tsukada, Naofumi,Yagura, Yasushige,Sato, Tetsuo,Inoue, Yoshio
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p. 1431 - 1434
(2007/10/03)
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- Substituent effects on the rate constants for the photo-claisen rearrangement of allyl aryl ethers
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The photochemistry of 11 substituted allyl 4-X- and 3-X-aryl ethers 3 (ArOCH2-CH=CH2) has been examined in both methanol and cyclohexane as solvents. The ethers react by the photo-Claisen rearrangement to give allyl substituted phenols as the major primary photoproducts, as expected from the well-established radical pair mechanism. The excited singlet state properties (absorption spectra, fluorescence spectra, fluorescence quantum yields, and singlet lifetimes) were compared with a parallel set of unreactive 4-X- and 3-X-anisoles 4. The excited-state properties of three substituted 4-X-aryl 4-(1-butenyl) ethers 14 (ArOCH2CH2-CH=CH2) were also examined. The model compounds 4 and the reactive allyl ethers 3 have essentially identical rate constants for the excited-state processes with the exception of khoms, the rate constant for homolytic cleavage from S1 of the allyl ethers to give the radical pair. The difference between the fluorescence quantum yields and/or singlet lifetimes for 3 and 4 were used to obtain values of khoms for all of the allyl ethers. These values exhibit a large substituent effect, spanning almost 2 orders of magnitude with electron-donating groups (CH3O, CH3) accelerating the reaction and electron-withdrawing ones (CN, CF3) slowing it down. The parallel range of rate constants observed in both methanol and cyclohexane indicates that ion pairs are not important intermediates in these rearrangements. Quantum yields of reaction (Φr) for several of the more reactive ethers demonstrate that neither these values nor rate constants of reaction (khomr) derived from them are reliable measures of the actual excited-state process. In fact, the khomr values are significantly lower than the khoms ones, indicating that the radical pairs undergo recombination to generate starting material. Finally, the khoms rate constants were found to parallel a trend for the change in bond dissociation energy (ΔBDE) for the O-C (allyl) bond of the allyl ethers, indicating that other possible substituent effects are of minor importance.
- Pincock, Alexandra L.,Pincock, James A.,Stefanova, Roumiana
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p. 9768 - 9778
(2007/10/03)
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- A biomimetic approach to dihydrobenzofuran synthesis
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A method for an acid-catalyzed construction of dihydrobenzofuran heterocycles (14) from 2-(2′-hydroxyethyl)quinone precursors 10 is presented. The putative oxonium ion intermediate 17 formed by an intramolecular hydroxyl cyclization followed by dehydration is reduced in situ by an added dihydroquinone source. Good to excellent yields of cyclized products are realized in all cases except for highly electron deficient systems, and these suffer reduction prior to oxonium ion formation. All products are monomeric and derived from a two-electron transfer except for 10g, which affords the dimeric dihydrobenzofuran. The amount of cyclization or reduction product is governed by the HOMO/LUMO gap between the quinone substrate and the dihydroquinone additive, and the product distribution can be adjusted by modifying the electronic properties of the added reducing agent.
- Benbow,Katoch-Rouse
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p. 4965 - 4972
(2007/10/03)
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- The preparation of chiral salicylaldehydes based on Kagan's ether
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Two related routes to chiral salicylaldehydes which are derivatives of Kagan's ether have been developed. One route which is particularly simple begins with 2,6-diallylphenol. Facile conversion to a substituted benzofuran and assemblage of the basic framework of Kagan's ether is followed by an ozonolysis of the benzofuran ring to reveal the hydroxyaldehyde functionality characteristic of salicylaldehydes.
- Harmata,Wu,Kahraman,Welch
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p. 3345 - 3359
(2007/10/03)
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- Synthesis of polyfluorinated aromatic polyesters
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Perfluoroalkylation of phenolic compounds by RFI/Na2S2O4 reagent system was used to synthesize fluorinated monomers useful in polycondensation reactions. A series of fluorinated aromatic polyesters was prepared
- Zhang, Li,Huang, Wei-Yuan
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- Alternative Lewis acids to effect Claisen rearrangement
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Yb(OTf)3 and DIBAL-H are developed as alternative Lewis acids for effecting Claisen rearrangement of allyl, crotyl and prenyl aryl ethers.
- Sharma,Ilangovan,Sreenivas, Punna,Mahalingam
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p. 615 - 618
(2007/10/03)
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- Essential oils from hairy root cultures and from fruits and roots of Pimpinella anisum
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Hairy root cultures of Pimpinella anisum were established following inoculation of aseptically grown plantlets with an A4 pRiA4 70 GUS strain of Agrobacterium rhizogenes. The essential oils from the hairy roots, maintained in four di
- Santos, Paula M.,Figueiredo, A. Cristina,Oliveira, M. Margarida,Barroso, Jose G.,Pedro, Luis G.,Deans, Stanley G.,Younus,Scheffer, Johannes J. C.
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p. 455 - 460
(2007/10/03)
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