- Structure and Reactivity of N-Heterocyclic Alkynyl Hypervalent Iodine Reagents
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Ethynylbenziodoxol(on)e (EBX) cyclic hypervalent iodine reagents have become popular reagents for the alkynylation of radicals and nucleophiles, but only offer limited possibilities for further structure and reactivity fine-tuning. Herein, the synthesis o
- Le Du, Eliott,Duhail, Thibaut,Wodrich, Matthew D.,Scopelliti, Rosario,Fadaei-Tirani, Farzaneh,Anselmi, Elsa,Magnier, Emmanuel,Waser, Jerome
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supporting information
p. 10979 - 10986
(2021/06/08)
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- Para-Selective C-H Borylation of Common Arene Building Blocks Enabled by Ion-Pairing with a Bulky Countercation
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The selective functionalization of C-H bonds at the arene para position is highly challenging using transition metal catalysis. Iridium-catalyzed borylation has emerged as a leading technique for arene functionalization, but there are only a handful of strategies for para-selective borylation, which operate on specific substrate classes and use bespoke ligands or catalysts. We describe a remarkably general protocol which results in para-selectivity on some of the most common arene building blocks (anilines, benzylamines, phenols, benzyl alcohols) and uses standard borylation ligands. Our strategy hinges upon the facile conversion of the substrates into sulfate or sulfamate salts, wherein the anionic arene component is paired with a tetrabutylammonium cation. We hypothesize that the bulk of this cation disfavors meta-C-H borylation, thereby promoting the challenging para-selective reaction.
- Mihai, Madalina T.,Williams, Benjamin D.,Phipps, Robert J.
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supporting information
p. 15477 - 15482
(2019/10/11)
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- Synthesis of N-Heteroaromatic Compounds through Cyclocarbonylative Sonogashira Reactions
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A protocol based on cyclocarbonylative Sonogashira reactions has been developed for the synthesis of nitrogen-containing heterocycles. The process is carried out under CO pressure, in the presence of a small amount of PdCl2(PPh3)sub
- Aronica, Laura Antonella,Albano, Gianluigi,Giannotti, Luca,Meucci, Elisa
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supporting information
p. 955 - 963
(2017/02/15)
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- Quadruple π stack of two perylene bisimide tweezers: A bimolecular complex with kinetic stability
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Self-assembly: A tweezer-type perylene bisimide (PBI) dyad self-assembles into a defined bimolecular complex composed of a quadruple PBI π stack with remarkable kinetic stability, which is unprecedented for π-stacked dye aggregates (see picture). These persistent supramolecular species are of considerable interest for the elucidation of functional properties of dye aggregates. Copyright
- Shao, Changzhun,Stolte, Matthias,Wuerthner, Frank
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supporting information
p. 7482 - 7486
(2013/07/26)
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- Synthesis of polycyclic sultams by palladium-catalyzed intramolecular cyclization
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A practical and high-yielding method for the synthesis of new sultams from readily available sulfonamides, 1-naphthylamine, and 2-halobenzyl bromides is reported. A variety of tricyclic, tetracyclic, and pentacyclic sultams have been prepared via palladiumcatalyzed, ligand-free intramolecular cyclization. Detailed mechanistic studies of the reaction pathway are also described.
- Majumdar,Mondal, Shovan,De, Nirupam
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scheme or table
p. 3127 - 3135
(2009/12/27)
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- Synthesis, in vitro and in vivo evaluation, and radiolabeling of aryl anandamide analogues as candidate radioligands for in vivo imaging of fatty acid amide hydrolase in the brain
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Fatty acid amide hydrolyase (FAAH) is one of the main enzymes responsible for terminating the signaling of endocannabinoids in the brain. Imaging FAAH in vivo using PET or SPECT is important to deeper understanding of its role in neuropsychiatric disorders. However, at present, no radioligand is available for mapping the enzyme in vivo. Here, we synthesized 18 aryl analogues of anandamide, FAAH's endogenous substrate, and in vitro evaluated their potential as metabolic trapping tracers. Interaction studies with recombinant FAAH revealed good to very good interaction of the methoxy substituted aryl anandamide analogues 17, 18, 19, and 20 with FAAH and they were identified as competing substrates. Compounds 17 and 18 did not display significant binding to CB1 and CB2 cannabinoid receptors and stand out as potential candidate metabolic trapping tracers. They were successfully labeled with 11C in good yields and high radiochemical purity and displayed brain uptake in C57BL/6J mice. Radioligands [11C]-17 and [ 11C]-18 merit further investigation in vivo.
- Wyffels, Leonie,Muccioli, Giulio G.,De Bruyne, Sylvie,Moerman, Lieselotte,Sambre, Johan,Lambert, Didier M.,De Vos, Filip
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supporting information; experimental part
p. 4613 - 4622
(2010/02/28)
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- Chemistry and folding of photomodulable peptides - Stilbene and thioaurone-type candidates for conformational switches
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Optimized synthetic strategies for the preparation of photoswitchable molecular scaffolds based on stilbene or on thioaurone chromophores and their conformationally directing properties, as studied by computations and by NMR spectroscopy, are addressed. For the stilbene peptidomimetics 1, 2 and 3, the length of connecting linkers between the chromophore and the peptide strands was varied, resulting in photochromic dipeptidomimetics with various flexibility. Building blocks of higher rigidity, based on para-substituted thioaurone (4 and 6) and meta-substituted thioaurone chromophores (5 and 7) are shown to have a stronger conformationally directing effect. Design, synthesis, theoretical and experimental conformational analyses are presented.
- Erdelyi, Mate,Varedian, Miranda,Skoeld, Christian,Niklasson, Ida B.,Nurbo, Johanna,Persson, Asa,Bergquist, Jonas,Gogoll, Adolf
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experimental part
p. 4356 - 4373
(2009/02/07)
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- ARYL FLUOROETHYL UREAS ACTING AS ALPHA 2 ADRENERGIC AGENTS
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The invention provides well-defined aryl fluoroethyl ureas that are useful as selective alpha2 adrenergic agonists. As such, the compounds described herein are useful in treating a wide variety of disorders associated with modulation of alpha2 adrenergic receptors.
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Page/Page column 20
(2008/12/07)
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- Radical dearomatization of benzene leading to phenanthridine and phenanthridinone derivatives related to (±)-pancratistatin
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The synthesis of the phenanthridinone nucleus common to the Amaryllidaceae series of natural products is achieved by a sequence involving tributylstannane-mediated, benzeneselenol-catalyzed addition of ortho-nitrogen functionalized aryl radicals to benzen
- Crich, David,Krishnamurthy, Venkataramanan
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p. 6830 - 6840
(2007/10/03)
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- A functional assay for heparin in serum using a designed synthetic receptor
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(Graph Presented) Excellent selectivity in highly competitive serum was displayed by a synthetic fluorescent receptor incorporating phenylboronic acid and ammonium groups for the therapeutic anticoagulant heparin. The concentration of heparin at clinicall
- Wright, Aaron T.,Zhong, Zhenlin,Anslyn, Eric V.
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p. 5679 - 5682
(2007/10/03)
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- Cyclization reactions of 2-alkynylbenzyl alcohol and 2-alkynylbenzylamine derivatives promoted by tetrabutylammonium fluoride
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The regioselectivity of the cyclization reaction of 2-ethynylbenzyl alcohol and 2-ethynylbenzylamine derivatives promoted by TBAF was investigated. Six-membered ring derivatives were obtained from the compounds, which have a butyl group on the triple bond. Whereas five-membered ring products were afforded from the substrates having hydrogen or aromatic substituents on the acetylene moiety. It was also concluded that both the tetrabutylammonium cation and fluoride anion were essential for the cyclization. Thus, the actual mechanism and catalytic cycle were also suggested.
- Hiroya, Kou,Jouka, Rumi,Kameda, Mitsuyoshi,Yasuhara, Akito,Sakamoto, Takao
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p. 9697 - 9710
(2007/10/03)
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- Characterization of the binding site of the histamine H3 receptor. 2. Synthesis, in vitro pharmacology, and QSAR of a series of monosubstituted benzyl analogues of thioperamide
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A series of monosubstituted benzyl analogues of the histamine H3 receptor antagonist thioperamide were synthesized and evaluated for their histamine H3 receptor activity on the guinea pig jejunum. Incorporation of Cl, Br, and I at th
- Windhorst, Albert D.,Timmerman, Henk,Worthington, Edward A.,Bijloo, Greetje J.,Nederkoorn, Paul H. J.,Menge, Wiro M. P. B.,Leurs, Rob,Herscheid, Jacobus D. M.
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p. 1754 - 1761
(2007/10/03)
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- Spiro-λ4-sulfanes with intramolecular sulfur-oxygen interactions: Syntheses and molecular structures
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Three novel N-acetylated spiro-λ4-sulfanes with five-membered spirorings (fused with aromatic rings) and with two N heteroatoms (in (1)) or with N and O heteroatoms (in (2) and (3)) in axial positions have been prepared and their molecular structures determined by X-ray diffraction. The molecular structures of compounds (1-3) show trigonal bipyramidal geometry about the central sulfur atom. The rather long axial S-N bonds(1.93 A)in he symmetric spiro-λ4-sulfane (1) exhibit the usual hypervalent character, whereas the S-N (1.73 and 1.80 A) and S-O (2.23 and 2.07 A) bond lengths in the unsymmetric spiro λ4-sulfanes (2) and (3) correspond to elongated covalent S-N bonds and highly polarized S-O hypervalent bonds, respectively. Each structure exhibits usual S-C(ar) bond lengths (1.79-1.81 A). The axial N-S-N/O and the equatorial C(ar)-S-C(ar) angles lie in the intervals 173-179°and 98-103°, respectively. The conformations of (1-3) including the single-cis-single-trans isomerism of the endocyclic and exocyclic amide parts, the shape of the spirorings, and the relative positions of the equatorial aromatic rings are discussed in detail. In (1-3) the exocyclic carbonyl-oxygen approaches the central sulfur atom by 2.90,2.73 and 2.71 A, respectively, leading to an effective intramolecular sulfur-oxygen interaction of 1,4-type. The S···O close contacts, however, do not alter appreciably the trigonal bipyramidal geometry about the central sulfur atom.
- Szabo,Kuti,Kapovits,Rabai,Kucsman, A.,Argay,Czugler,Kalman,Parkanyi
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- Oxidation during reductive cyclisations using Bu3SnH
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Reductive cyclisations using Bu3SnH include an "oxidation" step if the removal of an acidic proton from the intermediate cyclised radical, by Bu3SnH acting as a base, is favourable. A "pseudo" SRN1 mechanism is proposed.
- Bowman, W. Russell,Heaney, Harry,Jordan, Benjamin M.
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p. 10119 - 10128
(2007/10/02)
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