- Concave-Convex π-π Template Approach Enables the Synthesis of [10]Cycloparaphenylene-Fullerene [2]Rotaxanes
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The cycloparaphenylenes (CPPs) are a class of strained macrocycles that until 2008 were considered beyond the reach of organic synthesis. With its cyclic array of ten para-substituted phenylene rings, [10]CPP possesses a concave π-system that is perfectly preorganized for the strong supramolecular association of convex fullerenes such as C60. Although mechanically interlocked CPP architectures have been observed in the gas phase, the rational synthesis of bulk quantities has not been achieved yet, which is likely due to the fact that conventional template strategies are not amenable to CPP rings that lack heteroatoms. Here, we report the synthesis of two [2]rotaxanes in which a [10]CPP ring binds to a central fullerene bis-adduct and is prevented from dethreading by the presence of two bulky fullerene hexakis-adduct stoppers. The final step in the rotaxane synthesis is surprisingly efficient (up to ca. 40% yield) and regioselective because the fullerene acts as an efficient convex template, while [10]CPP acts as a supramolecular directing group, steering the reaction at the central fullerene exclusively toward two trans regioisomers. Comprehensive physicochemical studies confirmed the interlocked structure, shed light on the dynamic nature of the CPP-fullerene interaction, and revealed intriguing consequences of the mechanical bond on charge transfer processes. In light of recent advances in the synthesis of nanohoops and nanobelts, our concave-convex π-π templating strategy may be broadly useful and enable applications in molecular electronics or complex molecular machinery.
- Xu, Youzhi,Kaur, Ramandeep,Wang, Bingzhe,Minameyer, Martin B.,Gs?nger, Sebastian,Meyer, Bernd,Drewello, Thomas,Guldi, Dirk M.,Von Delius, Max
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Read Online
- Oxidative Kinetic Resolution of Cyclic Benzylic Ethers
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A manganese-catalyzed oxidative kinetic resolution of cyclic benzylic ethers through asymmetric C(sp3)?H oxidation is reported. The practical approach is applicable to a wide range of 1,3-dihydroisobenzofurans bearing diverse functional groups and substituent patterns at the α position with extremely efficient enantiodiscrimination. The generality of the strategy was further demonstrated by efficient oxidative kinetic resolution of another type of five-membered cyclic benzylic ether, 2,3-dihydrobenzofurans, and six-membered 6H-benzo[c]chromenes. Direct late-stage oxidative kinetic resolution of bioactive molecules that are otherwise difficult to access was further explored.
- Liu, Lei,Liu, Ziqiang,Ma, Yingang,Sun, Shutao
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supporting information
p. 176 - 180
(2020/10/30)
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- 1,3-Diradicals Embedded in Curved Paraphenylene Units: Singlet versus Triplet State and In-Plane Aromaticity
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Curved π-conjugated molecules and open-shell structures have attracted much attention from the perspective of fundamental chemistry, as well as materials science. In this study, the chemistry of 1,3-diradicals (DRs) embedded in curved cycloparaphenylene (
- Miyazawa, Yuki,Wang, Zhe,Matsumoto, Misaki,Hatano, Sayaka,Antol, Ivana,Kayahara, Eiichi,Yamago, Shigeru,Abe, Manabu
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supporting information
p. 7426 - 7439
(2021/05/29)
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- Coupling of Quinone Monoacetals with Vinyl Ethers Effected by Tetrabutylammonium Triflate: Regiocontrolled Synthesis of 2-Oxygenated Dihydrobenzofurans
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The synthesis of 2-oxygenated dihydrobenzofurans involving the [3 + 2] coupling of quinone monoacetals with vinyl ethers has been realized by tetrabutylammonium triflate catalysis. The reaction involves a new activation method of the acetal moiety in quinone monoacetals under acid-free conditions affording the highly oxygenated dihydrobenzofurans. This new activation mode was achieved by using the triflate anion catalyst for stabilization of the highly reactive cationic intermediate.
- Kamitanaka, Tohru,Tsunoda, Yusuke,Fujita, Yuriko,Dohi, Toshifumi,Kita, Yasuyuki
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supporting information
p. 9025 - 9029
(2021/11/24)
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- METHOD FOR PRODUCING ANNULAR COMPOUND
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PROBLEM TO BE SOLVED: To provide a method for producing an annular compound which can be produced in high yield. SOLUTION: There is provided a method for producing an annular compound represented by formula (M) comprising reacting particular two kinds of reactive compounds in the presence of a transition metal complex and an organic base. [In Formula (M), m' represents an integer of 5 to 15, and n' represents an integer of 1 to 10. Ara represents a group in which hydrogen atoms have been removed one by one from two sp3 carbons included in an arylene group or the like. However, at least one of Ara represents a group in which hydrogen atoms have been removed one by one from two sp3 carbons included in a cycloalkadiene, and these groups may have a substituent. Arb represents a group in which hydrogen atoms have been removed one by one from two sp3 carbons included in an arylene group or the like, and these groups may have a substituent.] SELECTED DRAWING: None COPYRIGHT: (C)2020,JPOandINPIT
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Paragraph 0149-0152
(2020/11/25)
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- Synthetic Entry to Polyfunctionalized Molecules through the [3+2]-Cycloaddition of Thiocarbonyl Ylides
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Here we present a comprehensive study on the [3+2]-cycloaddition of thiocarbonyl ylides with a wide variety of alkenes and alkynes. The obtained dihydro- and tetrahydrothiophene products serve as exceptionally versatile intermediates providing access to thiophenes, dienes, dendralenes, and vic-quarternary carbon centers. The use of high-pressure conditions enables thermally unstable, sterically encumbered or moderately reactive substrates to undergo the cycloaddition under mild conditions, thereby increasing the yield by up to 58percent. In addition, we showcase its utility by the formal syntheses of the pharmaceuticals NGB 4420 and tenilapine.
- Habiger, Christoph,Haut, Franz-Lucas,Korber, Johannes Nepomuk,Müller, Thomas,Magauer, Thomas,Mayer, Peter,Speck, Klaus,Wurst, Klaus
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supporting information
(2019/09/06)
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- Redox-Neutral α-C-H Functionalization of Pyrrolidin-3-ol
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A redox-neutral α-C-H oxygenation of commercially available pyrrolidin-3-ol with a monoprotected p-quinone generated an N-aryliminium ion intermediate, which reacted in situ with boronic acid nucleophiles to produce a series of cis-2-substituted pyrrolidin-3-ols. With this strategy, 8-epi-(-)-lentiginosine was synthesized from (3R,4R)-pyrrolidine-3,4-diol in three steps.
- Yi, Cheng-Bo,She, Zhi-Ying,Cheng, Yong-Feng,Qu, Jin
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supporting information
p. 668 - 671
(2018/02/09)
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- Experimental evidence for the formation of cationic intermediates during iodine(iii)-mediated oxidative dearomatization of phenols
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Iodine(iii)-based oxidants are commonly used reagents for the oxidative dearomatization of phenols. Having a better understanding of the mechanism through which these reactions proceed is important for designing new iodine(iii)-based reagents, catalysts, and reactions. We have performed a Hammett analysis of the oxidative dearomatization of substituted 4-phenylphenols. This study confirms that iodine(iii)-mediated oxidative dearomatizations likely proceed through cationic phenoxenium ions and not the direct addition of a nucleophile to an iodine-bound phenol intermediate.
- Tang, Ting,Harned, Andrew M.
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supporting information
p. 6871 - 6874
(2018/10/02)
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- Ph3P-mediated highly selective C(α)-P coupling of quinone monoacetals with R2P(O)H: Convenient and practical synthesis of: Ortho -phosphinyl phenols
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A highly selective Ph3P-mediated C(α)-P coupling reaction of quinone monoacetals with secondary phosphine oxides is developed to provide an effective method for the synthesis of a wide array of ortho-phosphinylphenols in good to excellent yields. This protocol can be adopted for scale-up synthesis directly from cheap and abundant phenols, and the products can be easily obtained in high yields by simple filtration without the use of organic extraction or chromatography.
- Shen, Ruwei,Zhang, Ming,Xiao, Jing,Dong, Chao,Han, Li-Biao
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supporting information
p. 5111 - 5116
(2018/11/24)
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- Lewis Acid-Mediated Site-Selective Synthesis of Oxygenated Biaryls from Methoxyphenols and Electron-Rich Arenes
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A rapid, efficient, and metal-free Lewis acid-mediated methodology has been developed for the site-selective synthesis of unsymmetrical oxygenated biaryls. This simple and efficient methodology furnished highly oxygenated and functionalized unsymmetrical biaryls in good to excellent yields by the direct oxidative coupling of electron-rich arenes to the α-position of carbonyl functionality of in situ generated masked benzoquinones.
- Sharma, Shivangi,Parumala, Santosh Kumar Reddy,Peddinti, Rama Krishna
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p. 9367 - 9383
(2017/09/22)
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- Direct synthesis of anilines and nitrosobenzenes from phenols
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A one-pot synthesis of anilines and nitrosobenzenes from phenols has been developed using an ipso-oxidative aromatic substitution (iSOAr) process. The products are obtained in good yields under mild and metal-free conditions. The leaving group effect on reactions that proceed through mixed quionone monoketals has also been investigated and a predictive model has been established.
- St Amant,Frazier,Newmeyer,Fruehauf,Read De Alaniz
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p. 5520 - 5524
(2016/07/06)
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- Iodobenzene and m-chloroperbenzoic acid mediated oxidative dearomatization of phenols
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Oxidative dearomatization of 2- and 4-substituted phenols to their corresponding benzoquinone monoketals by catalytic amount of iodobenzene, and m-CPBA as a co-oxidant has been achieved via in situ generation of PhIO2, a hypervalent iodine(V) s
- Taneja, Neha,Peddinti, Rama Krishna
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p. 3958 - 3963
(2016/08/11)
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- Unanticipated participation of HCl in nucleophilic chlorination reaction: Expedient route to meta chlorophenols
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o-Quinone monoketals participated in a 1,4-addition reaction with HCl furnishing m-chlorophenols in high yields. Several readily available o-quinone monoketals were selected to display the generality of this serendipitous and unprecedented reaction and the results are presented herein.
- Chittimalla, Santhosh Kumar,Bandi, Chennakesavulu
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supporting information
p. 15 - 19
(2015/12/23)
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- USE OF ANTROQIONONOL FOR TREATING OBESITY, AND PROCESS FOR PREPARATION OF ANTROQUINONOL
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Provided is the use of antroquinonol for manufacturing a composition or medicament for treating obesity. In addition, new processes for the total synthesis of antroquinonol and new compounds produced during the processes are disclosed.
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Paragraph 0081-0082
(2016/04/20)
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- Efficient Coupling Reaction of Quinone Monoacetal with Phenols Leading to Phenol Biaryls
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A simple and efficient synthesis of phenol biaryls by the cross-couplings of quinone monoacetals (QMAs) and phenols is reported. The Br?nsted acid catalytic system in 1,1,1,3,3,3-hexafluoro-2-propanol was found to be particularly efficient for this transformation. This reaction can be extended to the synthesis of various phenol biaryls, including sterically hindered biaryls, with yields ranging from 58 to 90 % under mild reaction conditions and in a highly regiospecific manner.
- Kamitanaka, Tohru,Morimoto, Koji,Tsuboshima, Kohei,Koseki, Daichi,Takamuro, Hitoho,Dohi, Toshifumi,Kita, Yasuyuki
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supporting information
p. 15535 - 15538
(2016/12/09)
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- Chemoselective Two-Directional Reaction of Bifunctionalized Substrates: Formal Ketal-Selective Mukaiyama Aldol Type Reaction
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In the presence of an acidic zwitterion bearing a highly stabilized carbanion, reactions of ω,ω-dialkoxy carbonyl compounds with ketene silyl acetals (KSA) resulted in an unusual molecular transformation; substitution reaction with the KSA at the ketal mo
- Yanai, Hikaru,Sasaki, Yuichi,Yamamoto, Yuki,Matsumoto, Takashi
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supporting information
p. 2457 - 2461
(2015/10/19)
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- Synthesis of o-chlorophenols via an unexpected nucleophilic chlorination of quinone monoketals mediated by N,N′-dimethylhydrazine dihydrochloride
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An unexpected nucleophilic chlorination of a quinone monoketal while carrying out a pyrazolidine synthesis has led to a general preparation of multisubstituted phenols. The products are obtained in good to high yields under mild conditions. The bridged pyrazolidines that were the original targets are obtained in the presence of a protic solvent. This journal is the Partner Organisations 2014.
- Yin, Zhiwei,Zhang, Jinzhu,Wu, Jing,Green, Riana,Li, Sihan,Zheng, Shengping
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supporting information
p. 2854 - 2858
(2014/05/06)
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- Lewis acid catalyzed [3+2] coupling of indoles with quinone monoacetals or quinone imine ketal
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The one-pot synthesis of benzofuroindolines and tetrahydroindolo[2,3-b] indoles was accomplished through a mild and concise [3+2] coupling of indoles and quinone monoacetals or quinone imine ketal promoted by a Lewis acid. A wide variety of benzofuroindolines and tetrahydroindolo[2,3-b]indoles were prepared in moderate to good yields. Copyright
- Shu, Chang,Liao, Li-Hua,Liao, Yi-Jun,Hu, Xiao-Yan,Zhang, Yong-Hong,Yuan, Wei-Cheng,Zhang, Xiao-Mei
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supporting information
p. 4467 - 4471
(2014/08/05)
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- The effects of cyclic conjugation and bending on the optoelectronic properties of paraphenylenes
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Cycloparaphenylenes (CPPs) have optoelectronic properties that are unique when compared to their acyclic oligoparaphenylene counterparts. The synthesis and characterization of two bent heptaphenyl-containing macrocycles has been achieved in order to probe
- Li, Penghao,Sisto, Thomas J.,Darzi, Evan R.,Jasti, Ramesh
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supporting information
p. 182 - 185
(2014/01/23)
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- A detour route for meta functionalization of phenols
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Cyclohexadienones participate in a two-step procedure, a Michael addition followed by aromatization, providing hitherto difficult-to-synthesize meta-functionalized phenol derivatives in good yield. Application of the developed approach is exemplified by synthesizing C-aryl acetophenones, C-aryl glycines, and elemicin - an allylphenol natural product. Georg Thieme Verlag Stuttgart · New York.
- Chittimalla, Santhosh Kumar,Kuppusamy, Rajesh,Bandi, Chennakesavulu
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p. 1991 - 1996
(2014/11/08)
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- Total synthesis of (±)-antroquinonol D
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Total synthesis of (±)-antroquinonol D, which is isolated from very expensive and rarely found Antrodia camphorata and which has potential anticancer properties, was achieved from 4-methoxyphenol. In addition, a Michael addition to dimethoxy cyclohexadien
- Sulake, Rohidas S.,Jiang, Yan-Feng,Lin, Hsiao-Han,Chen, Chinpiao
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p. 10820 - 10828
(2015/01/08)
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- Br?nsted acid-controlled [3 + 2] coupling reaction of quinone monoacetals with alkene nucleophiles: A catalytic system of perfluorinated acids and hydrogen bond donor for the construction of benzofurans
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We have developed an efficient Br?nsted acid-controlled strategy for the [3 + 2] coupling reaction of quinone monoacetals (QMAs) with nucleophilic alkenes, which is triggered by the particular use of a specific acid promoter, perfluorinated acid, and a solvent, fluoroalcohol. This new coupling reaction smoothly proceeded with high regiospecificity in regard with QMAs for introducing π-nucleophiles to only the carbon α to the carbonyl group, thereby providing diverse dihydrobenzofurans and derivatives with high yields, up to quantitative, under mild conditions in short reaction times. The choice of Br?nsted acid enabled us to avoid hydrolysis of the QMAs, which gives quinones, and the formation of discrete cationic species from the QMAs. Notably, further investigations in this study with regard to the acid have led to the findings that the originally stoichiometrically used acid could be reduced to a catalytic amount of 5 mol % loading or less and that the stoichiometry of the alkenes could be significantly improved down to only 1.2 equiv. The facts that only a minimal loading (5 mol %) of perfluoroterephthalic acid is required, readily available substrates can be used, and the regioselectivity can be controlled by the acid used make this coupling reaction very fascinating from a practical viewpoint.
- Hu, Yinjun,Kamitanaka, Tohru,Mishima, Yusuke,Dohi, Toshifumi,Kita, Yasuyuki
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p. 5530 - 5543
(2013/07/26)
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- A stereoselective approach to functionalized cyclohexenones
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A catalytic enantioselective approach to 4-hydroxy-6-methylcyclohex-2- enones is presented herein. The stereogenic information is generated through a copper-catalyzed 1,4-addition to p-benzoquinone monoketal using a chiral, BINOL-based (BINOL = 1,1′-bi-2-
- Meister, Anne C.,Sauter, Paul F.,Braese, Stefan
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supporting information
p. 7110 - 7116
(2013/11/06)
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- Double hetero-Michael addition of N -substituted hydroxylamines to quinone monoketals: Synthesis of bridged isoxazolidines
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A general synthesis of bridged isoxazolidines from a double hetero-Michael addition of N-substituted hydroxylamines to quinone monoketals has been developed. The different addition order of N-benzylhydroxylamine and N-Boc hydroxylamine is also discussed.
- Yin, Zhiwei,Zhang, Jinzhu,Wu, Jing,Liu, Che,Sioson, Kate,Devany, Matthew,Hu, Chunhua,Zheng, Shengping
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supporting information
p. 3534 - 3537
(2013/08/23)
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- Hypervalent iodine mediated synthesis of carbamate protected p-quinone monoimine ketals and p-benzoquinone monoketals
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A simple and efficient method for the synthesis of p-quinone monoimide ketals and p-benzoquinone monoketals by using a hypervalent iodine reagent, diacetoxyiodobenzene, has been developed. These two types of ketals are achieved from a single starting material by varying the reaction conditions.
- Bodipati, Naganjaneyulu,Peddinti, Rama Krishna
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experimental part
p. 4549 - 4553
(2012/07/14)
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- Tin tetrachloride-catalyzed regiospecific allylic substitution of quinone monoketals: An easy entry to benzofurans and coumestans
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A highly regioselective allylic substitution of quinone monoketals with a-oxoketene dithioacetals is achieved under the catalysis of only tin tetrachloride (1 mol%). The advantages of the reaction, including its simplicity, rapidity, low catalyst loading of inexpensive tin tetrachloride, mild conditions and; in particular, the regiospecificity, is proposed to be due to a pseudo-intramolecular process. This new synthetic method provides a facile [3+2] cycloaddition route to benzofurans and is highlighted by the synthesis of coumestans.
- Liu, Yingjie,Liu, Jingxin,Wang, Mang,Liu, Jun,Liu, Qun
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supporting information
p. 2678 - 2682
(2013/01/15)
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- Quinol derivatives as potential trypanocidal agents
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Quinols have been developed as a class of potential anti-cancer compounds. They are thought to act as double Michael acceptors, forming two covalent bonds to their target protein(s). Quinols have also been shown to have activity against the parasite Trypa
- Capes, Amy,Patterson, Stephen,Wyllie, Susan,Hallyburton, Irene,Collie, Iain T.,McCarroll, Andrew J.,Stevens, Malcolm F.G.,Frearson, Julie A.,Wyatt, Paul G.,Fairlamb, Alan H.,Gilbert, Ian H.
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experimental part
p. 1607 - 1615
(2012/04/23)
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- Efficient synthesis of oxygenated terphenyls and other oligomers: Sequential arylation reactions through phenol oxidation-rearomatization
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One by one: Starting from simple phenols, a diverse series of oxygenated terphenyl compounds can be prepared in a concise and practical manner using sequential arylation reactions involving phenol oxidation/rearomatization and quinone monoacetal intermediates (see scheme). Many of the terphenyl products can be used for preparing well-defined oligomers and, furthermore, contain valuable functional groups that can be transformed for further diversification. Copyright
- Dohi, Toshifumi,Kamitanaka, Tohru,Watanabe, Shohei,Hu, Yinjun,Washimi, Naohiko,Kita, Yasuyuki
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supporting information
p. 13614 - 13618
(2013/01/15)
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- Enantioselective total synthesis and studies into the configurational stability of bismurrayaquinone A
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Lost in rotation: The concise strategy of the first enantioselective total synthesis of bismurrayaquinone A utilized traceless stereochemical exchange to form an enantioenriched biphenyl core that was elaborated in a bidirectional manner to the natural pr
- Konkol, Leah C.,Guo, Fenghai,Sarjeant, Amy A.,Thomson, Regan J.
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supporting information; experimental part
p. 9931 - 9934
(2011/12/04)
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- [3 + 2] coupling of quinone monoacetals by combined acid-hydrogen bond donor
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The expeditious and efficient [3 + 2] coupling approach of quinone monoacetals 1 with alkene nucleophiles 2 by the action of an activated Bronsted acid in the presence of a hydrogen bond donor perfluorinated alcohol has been achieved. With the optimized combined acid, the reaction could proceed under mild conditions by only mixing the two reactants to afford the cycloadducts 3 in a short time (within 10 min) with good to quantitative yields.
- Dohi, Toshifumi,Hu, Yinjun,Kamitanaka, Tohru,Washimi, Naohiko,Kita, Yasuyuki
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supporting information; experimental part
p. 4814 - 4817
(2011/11/13)
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- Method for the Production of Substituted and Unsubstituted Cyclohexanone Monoketals
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The invention relates to a novel process for preparing and isolating known substituted and unsubstituted 1,4-cyclohexanone monoketals.
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Page/Page column 3
(2010/09/05)
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- Synthesis and chemical diversity analysis of bicyclo[3.3.1]non-3-en-2-ones
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Functionalized bicyclo[3.3.1]non-3-en-2-ones are obtained from commercially available phenols by a hypervalent iodine oxidation, enone epoxidation, epoxide thiolysis, and intramolecular aldol reaction sequence. Reaction optimization studies identified room temperature as well as microwave-mediated procedures, providing moderate to good yields (57-88%) in the thiophenol-mediated epoxide opening and intramolecular aldol reaction. In addition, the isolation of a key intermediate and in situ NMR studies supported the mechanistic hypothesis. The bicyclic ring products occupy novel chemical space according to ChemGPS and Chemaxon chemical diversity and cheminformatics analyses.
- Hammill, Jared T.,Contreras-García, Julia,Virshup, Aaron M.,Beratan, David N.,Yang, Weitao,Wipf, Peter
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experimental part
p. 5852 - 5862
(2010/09/11)
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- NOVEL PRODRUGS
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The present invention relates to novel prodrug compounds, or pharmaceutically acceptable salts thereof, which convert in vivo to the active species 4-(1-benzenesulfonyl-6-fluoro-1H-indol-2-yl)-4-hydroxy-cyclohexa-2,5-dienone. The prodrug compounds of the invention have dramatically improved solubility relative to 4-(1-benzenesulfonyl-6-fluoro-1H- indol-2-yl)-4-hydroxy-cyclohexa-2,5-dienone and, accordingly, can be easily formulated for administration to a patient. The prodrugs of the invention are therefore useful for the treatment cellular proliferation disorders, such as cancer.
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Page/Page column 24
(2010/11/04)
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- First synthesis of 9,10-dimethoxy-2-methyl-1,4-anthraquinone: A naturally occurring unusual anthraquinone
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The synthesis of 9,10-dimethoxy-2-methyl-1,4-anthraquinone, an unusual quinone, was achieved in five steps from p-benzoquinone. A Kochi-Anderson radical methylation features as the key step in the synthesis. The chemistry of a cyclopropa-1,4-anthracenedio
- Mal, Dipakranjan,Ray, Sutapa
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experimental part
p. 3014 - 3020
(2009/04/07)
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- Asymmetric synthesis of rubiginones A2 and C2 and their 11-methoxy regioisomers
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Convergent enantioselective syntheses of angucyclinone-type natural products rubiginones A2 (2) and C2 (1) and their 11-methoxy regioisomers 3a and 3b have been achieved by using two domino processes from a common enantiomerically pu
- Carreno, M. Carmen,Somoza, Alvaro,Ribagorda, Maria,Urbano, Antonio
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p. 879 - 890
(2007/10/03)
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- Development of a novel environmentally friendly electrolytic system by using recyclable solid-supported bases for in situ generation of a supporting electrolyte from methanol as a solvent: Application for Anodic methoxylation of organic compounds
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We have successfully developed a novel environmentally friendly electrolytic system using recyclable solid-supported bases for in situ generation of a supporting electrolyte from methanol as a solvent. It was found that solid-supported bases are electrochemically inactive at an electrode surface. It was also found that solid-supported bases dissociate methanol into methoxide anions and protons. Therefore, in the presence of solid-supported bases, it was clarified that methanol serves as both a solvent and a supporting electrolyte generated in situ. Anodic methoxylation of various compounds with solid-supported bases was carried out to provide the corresponding methoxylated products in good to excellent yields with a few exceptions. The methoxylated products and the solid-supported bases were easily separated by only filtration, and the desired pure methoxylated products were readily isolated simply by concentration of the filtrates. The separated and recovered solid-supported bases were recyclable for several times.
- Tajima, Toshiki,Fuchigami, Toshio
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p. 6192 - 6196
(2007/10/03)
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- Bromide-assisted oxidation of substituted phenols with hydrogen peroxide to the corresponding p-quinol and p-quinol ethers over WO4 2--exchanged layered double hydroxides
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A simple and efficient one-pot synthesis of p-quinols and their ethers occurs over tungstate-exchanged layered double hydroxides (WO4 2--LDHs), which catalyze the bromide-assisted oxidation of substituted phenols to the corresponding 4-alkoxy- and 4-hydroxycyclohexa-2,5- dienones in high yields (see scheme).
- Sels,De Vos,Jacobs
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p. 310 - 313
(2007/10/03)
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- Synthesis of Azobenzenes from Quinone Acetals and Arylhydrazines
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Direct reaction between quinone bisacetals and arylhydrazines gives azobenzenes. The presence of catalytic amounts of cerium ammonium nitrate strongly accelerates the reaction. When the bisacetal has a substituent at the 2,5-cyclohexadiene framework, only one regioisomer is formed. The method represents a simple, mild, and novel synthetic access to differently substituted azocompounds in high to excellent yield.
- Carreno, M. Carmen,Mudarra, Gerardo Fernandez,Merino, Estibaliz,Ribagorda, Maria
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p. 3413 - 3416
(2007/10/03)
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- 4-(1-(SULFONYL)-1H-INDOL-2-YL)-4-(HYDROXY)-CYCLOHEXA-2,5-DIENONE COMPOUNDS AND ANALOGS THEREOF AS THERAPEUTIC AGENTS
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This invention pertains to certain 4-(1-(sulfonyl)-1H-indol-2-yl)-4-(hydroxy)-cyclohexa-2,5-dienone compounds, and analogs thereof, including compounds of the following formula, which are, inter alia, antiproliferative agents, anticancer agents, and/or thioredoxin/thioredoxin reductase inhibitors: formula (I) wherein: Ar is a 1-(sulfonyl)-1H-indol-2-yl group; the bond marked α is independently: (a) a single bond; or: (b) a double bond; the bond marked β is independently: (a) a single bond; or: (b) a double bond; the group -ORO is independently: (a) -OH; (b) an ether group (e.g., -OMe); or: (c) an acyloxy (i.e., reverse ester) group (e.g., -OC(=O)Me); each of R2, R3, R5, and R6, is independently a ring substituent and is: (a) H; (b) a monovalent monodentate substituent; or: (c) a ring substituent which, together with an adjacent ring substituent, and together with the ring atoms to which these ring substituents are attached, form a fused ring; and pharmaceutically acceptable salts, esters, amides, solvates, hydrates, and protected forms thereof. The present invention also pertains to pharmaceutical compositions comprising such compounds, and the use of such compounds and compositions, both in vitro and in vivo, for example, in the treatment of proliferative conditions, (e.g., cancer), and/or conditions mediated by thioredoxin/thioredoxin reductase.
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Page/Page column 100
(2008/06/13)
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- Electrochemically-induced spirolactonization of α-(methoxyphenoxy)alkanoic acids into quinone ketals
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Anodic oxidation of two series of α-(2)- and α-(4-methoxyphenoxy)alkanoic acids were studied both at the analytical and preparative scales in order to delineate mechanistic aspects of electrochemically induced spirolactonization and to develop synthetically useful orthoquinone bis- and monoketals. Although α-monomethylated carboxylic acids and acetic acid derivatives do not undergo any spiroannulation, α-dimethylated carboxylic acids furnished spirolactones in high yields. A gem-dimethyl effect is invoked to explain these differences in cyclization capacity. Electrooxidation conditions can be selected to furnish either quinone spirolactone bis- or monoketals. Chemoselective monohydrolysis of bisketals can also be accomplished in a stepwise fashion to furnish the corresponding spirolactone monoketals, but the ortho compound unfortunately dimerized in situ via a Diels-Alder process. An ECEC pathway is proposed to rationalize the observed spirolactonizations on the basis of cyclic voltammetry analyses.
- Deffieux, Denis,Fabre, Isabelle,Courseille, Christian,Quideau, Stephane
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p. 4458 - 4465
(2007/10/03)
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- Synthesis of 5-substituted 4,4-disubstituted 2-cyclohexen-1-ones by electro-generated base promoted Michael addition of 4,4-disubstituted 2,5-cyclohexadien-1-ones
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5-Substituted 4,4-dialkoxy-2-cyclohexen-1-ones were electro-synthesized from 4,4-disubstituted 2,5-cyclohexadien-1-ones, which were obtained from 1,4-dialkoxybenzene derivatives by electrolysis, by electro-generated base (EG-base)-promoted Michael additio
- Torii, Sigeru,Hayashi, Naoya,Kuroboshi, Manabu
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p. 599 - 600
(2007/10/03)
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- π-Facial Diastereoselection in Diels-Alder Reactions of (R)-4-[(p-Tolylsulfinyl)methyl]quinols
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Diels-Alder reactions of a range of (R)-4-hydroxy-4-[(p-tolylsulfinyl)methyl]-2,5-cyclohexadienones with cyclopentadiene and 1,3-pentadiene proceed in a total π-facial diastereoselective manner from the C-4 OH side. Ab initio calculations at the RHF/6-31G
- Carre?o, M.Carmen,González, Manuel Pérez,Houk
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p. 9128 - 9137
(2007/10/03)
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- Oxidation with hypervalent iodine reagents. Part II: Novel cyclohexadienones as precursors for the synthesis of anthraquinones
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The oxidation of substituted phenols with phenyliodonium diacetate in methanol was found to afford 2,4-cyclohexadienones, 2,5-cyclohexadienones or mixtures of isomers, depending on the substrate being oxidized. Annulation of these cyclohexadienones with the anion of 3-cyanophthalide afforded anthraquinones in high yields.
- Mitchell, Anthony S.,Russell, Richard A.
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p. 4387 - 4410
(2007/10/03)
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- An efficient, simple and inexpensive method for the preparation of 1,4-benzoquinone monoketals via anodic oxidation of 1,4-dimethoxybenzenes
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Anodic oxidation of a series of 1-substituted-2,5-dimethoxybenzenes gives 2-substituted-1,1,4,4-tetramethoxycyclohexa-2,5-dienes in almost quantitative crude yield. Selective monohydrolysis of these bis-ketals is possible in many cases, and gives 3-substi
- Gautier,Lewis,McKillop,Taylor
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p. 2989 - 3008
(2007/10/02)
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- Anodic Oxidation of Aryl Propargyl and Aryl Allyl Ethers at a Platinum Electrode
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The oxidation reactions of aromatic 3,3-sigmatropic systems have been investigated under different conditions viz. (a) anodic oxidation in amphiprotic and aprotic media, (b) reaction with (diacetoxyiodo)benzene and (c) reaction promoted by ceric ammonium nitrate.
- Dhanalekshmii, Savithri,Balasubramanian, Kalpattu Kuppusamy,Venkatachalam, Chittoor Sivamakris.
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p. 6387 - 6400
(2007/10/02)
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- Phenolic Oxidations with Phenyliodonium Diacetate
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Phenyliodonium diacetate (PIDA) in methanol interacts smoothly with phenols to yield p-quinones, o-quinones, 4,4-dialkoxycyclohexa-2,5-dienones or 4-alkyl-4-alkoxycyclohexa-2,5-dienones, dependant on the constitution of the phenolic substrate.The reactions proceed in mild conditions and good yields and are synthetically useful.
- Pelter, Andrew,Elgendy, Said M. A.
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p. 1891 - 1896
(2007/10/02)
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- Spiro-Fused 2,5-Cyclohexadienones from Thermal 1,3-Shifts in Quinol Vinyl Ethers. Reactions in Nonbenzenoid Systems and Limitations of the Chemistry
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Addition of functionalized organolithium compounds to quinone monoketals furnished 4-hydroxy-2,5-cyclohexadienone derivatives.The 4-hydroxyl group of these molecules was then transformed into a vinyl ether, and the thermal -shift chemistry of these f
- Swenton, John S.,Bradin, David,Gates, Bradley D.
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p. 6156 - 6163
(2007/10/02)
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- Electrochemical behaviour of 3,3-sigmatropic systems - Anodic oxidation of aryl allyl ethers and aryl propargyl ethers
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The electrochemical oxidation of a few methoxy substituted aromatic 3,3-sigmatropic systems yielded mixed quinone monoketals in aqueous methanol and dimerised products in anhydrous acetonitrile.
- Dhanalekshmi,Balasubramanian,Venkatachalam
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p. 7591 - 7592
(2007/10/02)
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- The Unusually Slow Hydrolysis Rate of Silyl Methyl Ketals in Benzoquinone Systems. The Question of Siloxy Stabilization of an Adjacent Positive Charge and Stereoelectronic Effects on Ketal Hydrolysis
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The kinetics of the acid-catalyzed monohydrolysis of six quinone bisketals were studied under pseudo-first-order conditions.The tert-butyldimethylsilyl methyl and the tert-butyldiphenylsilyl methyl ketals respectively hydrolyse about 400 times slower than does the corresponding dimethyl ketal and react nearly at the rate of the ethylene glycol ketal.An important consideration in understanding these results was the carbonium ion stabilizing ability of the siloxy substituent.Thus, ? and ?+ values for the tert-butyldimethylsiloxy and the tert-butyldiphenylsiloxy groups were measured.These values indicated that siloxy groups are nearly as effective as a methoxy group in stabilizing a positive center provided a low-energy conformer is available for interaction of the oxygen nonbonding electron pair with the ?-center.If delocalization of the oxygen lone-pair electrons by the silicon is important, it does not manifest itself in the ? or ?+ values.The data collected also illustrate the strong conformational dependence of siloxy groups interacting with ?-systems, and it is this effect that is thought to be the major contributor to the lower rate of hydrolysis observed for the silyl methyl ketal moieties in these quinone systems.
- Stern, Alan J.,Swenton, John S.
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p. 2953 - 2958
(2007/10/02)
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- PHENOLIC OXIDATION WITH (DIACETOXYIODO)BENZENE
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(Diacetoxyiodo)benzene oxidises quinols and extended quinols to the corresponding quinones smoothly and in high yield.Excess of the reagent in methanol with monohydric phenols directly yields p-quinone ketals, also in good yields. 4-Alkyl and 4-alkoxyphenols give the corresponding 4-alkyl-4-methoxycyclohexadienones and 4-alkoxy-4-methoxycyclohexadienones.
- Pelter, Andrew,Elgendy, Said
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p. 677 - 680
(2007/10/02)
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