34452-56-7Relevant academic research and scientific papers
Covalent Adaptable Networks with Tunable Exchange Rates Based on Reversible Thiol–yne Cross-Linking
Du Prez, Filip E.,Guerre, Marc,Maes, Diederick,Unal, Kamil,Van Herck, Niels,Winne, Johan M.
supporting information, p. 3609 - 3617 (2020/02/04)
The design of covalent adaptable networks (CANs) relies on the ability to trigger the rearrangement of bonds within a polymer network. Simple activated alkynes are now used as versatile reversible cross-linkers for thiols. The click-like thiol–yne cross-linking reaction readily enables network synthesis from polythiols through a double Michael addition with a reversible and tunable second addition step. The resulting thioacetal cross-linking moieties are robust but dynamic linkages. A series of different activated alkynes have been synthesized and systematically probed for their ability to produce dynamic thioacetal linkages, both in kinetic studies of small molecule models, as well as in stress relaxation and creep measurements on thiol–yne-based CANs. The results are further rationalized by DFT calculations, showing that the bond exchange rates can be significantly influenced by the choice of the activated alkyne cross-linker.
A facile and reliable method for the synthesis of tetrabenzoporphyrin from 4,7-dihydroisoindole
Filatov, Mikhail A.,Cheprakov, Andrei V.,Beletskaya, Irina P.
, p. 3468 - 3475 (2008/02/12)
A new route to tetrabenzoporphyrins from the closest possible precursor of the unstable isoindole was developed. A key feature of this route is a dramatic facilitation of the aromatization of annelated rings, which is the most serious bottleneck in previo
Synthesis of a fluorine-18 labeled derivative of epibatidine for in vivo nicotinic acetylcholine receptor PET imaging
Dolci, Lilian,Dolle, Frederic,Valette, Heric,Vaufrey, Francoise,Fuseau, Chantal,Bottlaender, Michel,Crouzel, Christian
, p. 467 - 479 (2007/10/03)
Epibatidine (exo-2-(2'-chloro-5'-pyridyl)-7-azabicyclo[2.2.1]heptane), a natural compound isolated from the skin of the Ecuadorian poison frog Epipedobates tricolor, is the most potent nicotinic acetylcholine receptor (nAChR) agonist reported to date. In order to visualize and quantify in vivo these receptors in human brain using Positron Emission Tomography (PET), [18F]norchlorofluoroepibatidine (exo-2-(2'-[18F]fluoro-5'-pyridyl)-7-azabicyclo[2.2.1]heptane), a fluorine-18 (t(1/2): 110min) radiolabeled derivative of epibatidine has been designed. The corresponding 2'-bromo-, 2'-iodo- and 2'-nitro exo-2-(5'-pyridyl)-7-azabicyclo[2.2.1]heptane analogues as labeling precursors, as well as norchlorofluoroepibatidine as a reference compound have been synthesized by reductive, stereoselective, palladium-catalyzed Heck-type coupling between an N-Boc protected azanorbornene and the corresponding halopyridine. [18F]Norchlorofluoroepibatidine has been radiolabeled with fluorine-18 by nucleophilic aromatic substitution from the corresponding Boc-protected halo- and nitro precursors using [18F]FK-K222 complex in DMSO by conventional heating (at 150-180°C for 10min) or microwave activations (at 100 Watt, for 1 to 2.5min), followed by TFA-removal of the protective group. Typically, using the microwave activation procedure, 60-80mCi (2.22-2.96 GBq) of pure [18F]norchlorofluoroepibatidine could be obtained in less than 2h (110-115min) from the bromo labeling precursor, with specific radioactivities of 1.5-2.5Ci/μmol (55.5-92.5GBq/μmol) calculated for End of Bombardment. The preliminary PET experiments in baboon (Papio papio) with [18F]norchlorofluoroepibatidine show a high uptake and a rapid accumulation of the radiotracer into the brain within 30min. In the thalamus, a nAChR rich area, uptake of radioactivity reached a maximum at 40min (10% I.D./100mL tissue). The ratio of radioactivity thalamus/cerebellum (the latter being a nAChR poor area) was 2 at 40min and increased with time, up to 4.3 at 160min. Its specific regiodistribution and its high ratio of specific-to-nonspecific binding confirm the ideal profile of [18F]norchlorofluoroepibatidine as a suitable radioligand for PET imaging of nAChRs in the brain. Copyright (C) 1999 Elsevier Science Ltd.
2-(Het)aryl-substituted 7-azabicyclo[2.2.1]heptane systems
Otten, Albert,Namyslo, Jan Christoph,Stoermer, Martin,Kaufmann, Dieter E.
, p. 1997 - 2001 (2007/10/03)
Epibatidine (1) is a recently discovered trace alkaloid found in the skin of a Latin-Amencan poisonous frog. Its remarkably high analgetic activity is accompanied by high toxicity. Therefore, in order to tune its biological activity, a convergent and effi
A simplified method for the preparation of ethynyl P-tolyl sulfone and ethynyl phenyl sulfone
Chen,Trudell
, p. 3149 - 3155 (2007/10/02)
Silica gel mediated desilylation of aryl 2-(trimethylsilyl)ethynyl sulfones was found to greatly simplify the synthesis of the acetylenic sulfones, ethynyl p-tolyl sulfone 1 and ethynyl phenyl sulfone 2. Each were easily prepared in good yield and high purity on a multigram scale from bis(trimethylsilyl)acetylene 3.
Aromatic stabilization of the triarylborirene ring system by tricoordinate boron and facile ring opening with tetracoordinate boron
Eisch, John J.,Shafii, Babak,Odom, Jerome D.,Rheingold, Arnold L.
, p. 1847 - 1853 (2007/10/02)
To remove uncertainties in the apparent C=C and B-C bond lengths of the borirene ring, as previously estimated from an X-ray crystallographic analysis of trimesitylborirene, the unsymmetrically substituted 2-(2,6-dimethylphenyl)-1,3-dimesitylborirene was
Selenosulfonation of Acetylenes: Preparation of Novel β-(Phenylseleno)vinyl Sulfones and Their Conversion to Acetylenic and β-Functionalized Sulfones
Back, Thomas G.,Collins, Scott,Kerr, Russell G.
, p. 3077 - 3084 (2007/10/02)
The 1,2-additions of Se-phenyl p-tolueneselenosulfonate (1) to acetylenes under mild conditions afford β-(phenylseleno)vinyl sulfones 3, generally in high yields.The reaction is highly regioselective (anti-Markovnikov) and stereoselective (anti) and proceeds via a free-radical chain mechanism initiated by the thermolysis of the selenosulfonate.The oxidation of β-(phenylseleno)vinyl sulfones with m-chloroperbenzoic acid generates the corresponding selenoxides 4, which undergo syn or base-catalyzed elimination to furnish acetylenic sulfones 5.Base-catalyzed alcoholyses of selenoxides 4 in methanol or ethylene glycol produce β-keto sulfone ketals 8 or 10, respectively.Free β-keto sulfones 11 are formed by the acid-catalyzed hydrolysis of the corresponding β-(phenylseleno)vinyl sulfones 3.
