- An efficient and regioselective direct aromatic iodination using iodine and nitrogen dioxide
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Direct iodination of a variety of aromatic compounds is achieved by using nitrogen dioxide as an oxidant in addition to iodine. The reaction affords aromatic monoidodides m high yields with high para-regioselectivity. 4,4'- Diiodo binuclear compounds are also obtained effectively by controlling the stoichiometry.
- Noda, Yumiki,Kashima, Mikito
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- Direct Acetoxylation of Arenes
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Acetoxylation of arenes is an important reaction and an unmet need in chemistry. We report a metal-free, direct acetoxylation reaction using sodium nitrate under an anhydrous environment of trifluoroacetic acid, acetic acid, and acetic anhydride. Arenes (31 examples), with oxidation potentials (Eox, in V vs SCE) lower than benzene (2.48 V), were acetoxylated with good yields and regioselectivity. A stepwise, single electron-transfer mechanism is proposed.
- Hong Nguyen, Thi Anh,Hou, Duen-Ren
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supporting information
p. 8127 - 8131
(2021/08/23)
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- Structure–activity relationships and docking studies of hydroxychavicol and its analogs as xanthine oxidase inhibitors
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Hydroxychavicol (HC), which is obtained from the leaves of Piper betle LINN. (Piperaceae), inhibits xanthine oxidase (XO) with an IC50 value of 16.7μM, making it more potent than the clinically used allopurinol (IC50=30.7μM). Herein, a structure–activity relationship analysis of the polar part analogs of HC was conducted and an inhibitor was discovered with a potency 13 times that of HC. Kinetic studies have revealed that HC and its active analog inhibit XO in an uncompetitive manner. The binding structure prediction of these inhibitor molecules to the XO complex with xanthine suggested that both compounds (HC and its analog) could simultaneously form hydrogen bonds with xanthine and XO.
- Nishiwaki, Keiji,Ohigashi, Kanae,Deguchi, Takahiro,Murata, Kazuya,Nakamura, Shinya,Matsuda, Hideaki,Nakanishi, Isao
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p. 741 - 747
(2018/07/05)
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- Chelating Bis-N-heterocyclic Carbene-Palladium(II) Complexes for Oxidative Arene C-H Functionalization
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Bis-N-heterocyclic carbene (NHC)-chelated palladium(II) complexes have been synthesized, characterized fully including single-crystal X-ray structural analyses, and utilized for the first time toward catalytic oxidative C-H functionalization of arenes with PhI(OAc)2 and N-bromosuccinimide. (Figure Presented).
- Desai, Sai Puneet,Mondal, Moumita,Choudhury, Joyanta
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p. 2731 - 2736
(2015/06/30)
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- Copper-catalyzed Z-selective semihydrogenation of alkynes with hydrosilane: A convenient approach to cis-alkenes
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A copper catalyst generated in situ from widely available copper salt and imidazolium salt in the presence of t-BuOK showed high efficiency for the semihydrogenation of a wide range of internal and terminal alkynes to their corresponding alkenes without obvious over-reduction. Functional groups, such as hydroxyl, nitro, halides, and amino, etc. were tolerated. The Z/E ratios of the obtained alkenes were generally >99%. Finally, semireduction of bulky alkynes also went smoothly.
- Wang, Guang-Hui,Bin, Huai-Yu,Sun, Miao,Chen, Shu-Wei,Liu, Ji-Hong,Zhong, Chong-Min
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p. 2175 - 2179
(2014/03/21)
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- CHEMOTHERAPEUTIC FOR INDUCING AN MSH2 DEPENDENT APOPTOTIC PATHWAY
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Active compounds include compounds of Formula I and Formula II are described: along with compositions containing the same and methods of use thereof.
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Paragraph 0109-0110
(2014/11/11)
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- Negishi cross-coupling reaction as a route to isocombretastatins
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A series of isocombretastatins A has been synthesized by a new method based on the Negishi cross-coupling reaction in 19-84% yields. Five of the synthesized compounds exhibit high cytotoxic activity in nanomolar concentrations (IC50 = 1-100 n) towards Jurkat, K562, Colo357, and A549 cell lines. Georg Thieme Verlag Stuttgart · New York.
- Malysheva, Yulia B.,Buchvalova, Svetlana Y.,Svirshchevskaya, Elena V.,Fokin, Valery V.,Fedorov, Alexey Y.
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supporting information
p. 1772 - 1776
(2013/09/12)
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- Palladium-catalyzed acetoxylation of arenes by novel sulfinyl n-heterocyclic carbene ligand complexes
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A series of novel ligands based on N-heterocyclic carbene and sulfoxide functionalities have been prepared and characterized. Pd(II) complexes have been synthesized by transmetalation from the corresponding NHC-Ag derivatives, and their behavior as catalysts has been studied in arene C-H bond oxidative activation. Studies conducted toward the elucidation of the reaction mechanism of the acetoxylation suggest a C-H activation step at Pd(IV) rather than Pd(II) intermediates.
- Tato, Francisco,Garcia-Dominguez, Andres,Cardenas, Diego J.
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supporting information
p. 7487 - 7494
(2014/04/03)
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- Total synthesis of "Aliskiren": The first renin inhibitor in clinical practice for hypertension
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We report a "macrocycle route" toward aliskiren, a drug presently marketed for the treatment of hypertension, using a highly stereocontrolled approach starting from a common "isopropyl chiron". Highlights of the synthesis include a challenging RCM reaction to produce a nine-membered unsaturated lactone, a highly stereoselective catalytic Du Bois aziridination, and a regio- and diastereoselective aziridine ring-opening to a vicinal amino alcohol.
- Hanessian, Stephen,Guesne, Sebastien,Chenard, Etienne
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supporting information; scheme or table
p. 1816 - 1819
(2010/09/16)
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- Synthesis of amide group containing triphenylene derivatives as discotic liquid crystals and organic gelators
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Intermolecular hydrogen bond is an efficient way to anchor columnar assembly of discotic liquid crystals, and would result in more ordered columnar mesphase and faster charged carrier mobility. In this report, a series of peripheral functionalized triphenylene derivatives, C18H 6(OC6H13)4(OCH2CONHR) 2, which contains amide groups at the 2,7-positions, have been synthesized. The polarized optical microscopy (POM) and differential scanning calorimetry (DSC) results showed that these compounds exhibit hexagonal columnar mesophases. The triphenylene derivatives gelate in the solution of octane, petroleum ether, cyclohexane and p-xylene and form stable organic gels. The xerogels formed from organic solvents were analyzed by scanning electron microscope (SEM) and showed fiber-like or sponge-like morphology. It is demonstrated that intermolecular hydrogen bonds stabilize the columnar molecular organization and assembly in mesomorphic state and organic gel. Copyright Taylor & Francis Group, LLC.
- Bai,Zhao,Hu,Wang,Shimizu
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experimental part
p. 60 - 76
(2011/08/07)
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- 4,5-Diaryl-1H-pyrrole-2-carboxylates as combretastatin A-4/lamellarin T hybrids: Synthesis and evaluation as anti-mitotic and cytotoxic agents
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The 4,5-diarylated-1H-pyrrole-2-carboxylates 3-8 have each been prepared as hybrids of the potent anti-mitotic agent combretastatin A-4 (1) and the similarly active marine alkaloid lamellarin T (2). The key steps involved selective lithium-for-halogen exchange at C5 within the N-PMB protected 4,5-dibromopyrrole 22 and Negishi cross-coupling of the derived zincated species with the relevant aryl iodide. The ensuing 5-aryl-4-bromopyrrole then engaged in Suzuki-Miyaura cross-coupling with the appropriate arylboronic acid to give the 4,5-diarylated pyrroles 4, 6 and 8. TFA-promoted removal of the N-PMB group within these last compounds then gave the N-unsubstituted congeners 3, 5 and 7. Compounds 3-8 have all been evaluated for their anti-mitotic and cytotoxic properties and two of them, 3 and 5, display useful activities although they are less potent than combretastatin A-4. Crown Copyright
- Banwell, Martin G.,Hamel, Ernest,Hockless, David C.R.,Verdier-Pinard, Pascal,Willis, Anthony C.,Wong, David J.
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p. 4627 - 4638
(2007/10/03)
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- Synthesis and biological activity of the tea catechin metabolites, M4 and M6 and their methoxy-derivatives
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Syntheses are reported for metabolites M4 (1) and M6 (2) of the green tea polyphenols epicatechin (EC) and epigallocatechin (EGC) and their gallate derivatives. Several methoxy-derivatives of 1 and 2 were also prepared. Compounds 1 and 2 were evaluated for growth inhibitory activity against a panel of immortalized and malignant human cell lines with 1 being the more active compound. The possible antiinflammatory activity of 1 and its trimethoxy derivative was also evaluated. Neither compound inhibited the release of arachidonic acid, although 1 inhibited NO production by 50% at 20 μM.
- Lambert, Joshua D.,Rice, Joseph E.,Hong, Jungil,Hou, Zhe,Yang, Chung S.
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p. 873 - 876
(2007/10/03)
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- Gaining diversity in solid-phase synthesis by modulation of cleavage conditions from hydroxymethyl-based supports. Application to lamellarin synthesis
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The application of a number of Lewis acids as a cleavage/deprotection method in the solid-phase synthesis of organic molecules can render several analogues, which, after purification, can be submitted for biological evaluation.
- Cironi, Pablo,Cuevas, Carmen,Albericio, Fernando,álvarez, Mercedes
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p. 8669 - 8675
(2007/10/03)
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- Iodinated biaryls synthesized by the direct dehydrodimerization of iodoarenes using phenyliodine(III) bis(trifluoroacetate) (PIFA)
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Multiply iodinated biaryls can be prepared in yields up to 75% by direct oxidative coupling reaction of the iodinated arenes. The PIFA-mediated dehydrodimerization is superior to all other known methods. The developed protocol is reliable and easy to perform.
- Mirk, Daniela,Willner, Alexander,Froehlich, Roland,Waldvogel, Siegfried R.
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p. 675 - 681
(2007/10/03)
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- Isopropoxy as a masked hydroxy group in aryl oxidative coupling reactions
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Mono- and dihydroxy substituted triphenylenes have been prepared in a one-pot biphenyl/phenyl oxidative coupling reaction, in which isopropoxy acts as a masking/protecting group.
- Bushby,Lu
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p. 763 - 767
(2007/10/03)
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- The synthesis of (E) and (Z)-combretastatins A-4 and a phenanthrene from Combretum caffrum
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The synthesis of the trans stilbene E-combretastatin A-4 has been achieved via a Horner-Wittig reaction of (3,4,5- trimethoxybenzyl)diphenylphosphine oxide. The anticancer drug Z- combretastatin A-4 was prepared by the hydroboration/protonation of a diaryl- alkyne.
- Lawrence, Nicholas J.,Ghani, Fazni Abdul,Hepworth, Lucy A.,Hadfield, John A.,McGown, Alan T.,Pritchard, Robin G.
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p. 1656 - 1660
(2007/10/03)
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- Cyclization pathways of a (Z)-stilbene-derived bis(orthoquinone monoketal)
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Lead tetraacetate mediated oxidation of a (Z)-bisphenolic stilbene derivative affords a bis(orthoquinone monoketal) product. Thermolysis studies of this highly unsaturated dione reveal that sigmatropic hydrogen shifts, followed by either of two distinct solvolytic ring closures, constitute the predominate reaction pathways under heating. No evidence for a desired 6π electron electrocyclization was forthcoming.
- Feldman, Ken S.
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p. 4983 - 4990
(2007/10/03)
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- Triphenylene-based discotic-liquid-crystalline polymers: A universal, rational synthesis
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A simple, regiospecific synthesis of main-chain, triphenylene-based discotic-liquid-crystalline polymers is described in which the key step is the assembly of the triphenylene nucleus through the oxidative coupling of phenyl and biphenyl residues. Hence, treatment of a mixture of 3,3′-bis(hexyloxy)-4,4′-dimethoxybiphenyl and 1,2-bis(hexyloxy)benzene with ferric chloride in dichloromethane followed by a reductive, methanol workup gives 2,7-dimethoxy-3,6,10,11-tetrakis(hexyloxy)triphenylene, 7. The 2,7-linked main-chain polymer 8 is produced by demethylation and condensation with 1,11-dibromoundecane, has average molecular weight 24 000, and Dh mesophase range of 98-118 °C. The 3,6- and 2,3-linked polymers were prepared in a similar manner.
- Boden, Neville,Bushby, Richard J.,Cammidge, Andrew N.
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p. 924 - 926
(2007/10/02)
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