147410-32-0Relevant academic research and scientific papers
Hybrid Organic Lead Iodides: Role of Organic Cation Structure in Obtaining 1D Chains of Face-Sharing Octahedra vs 2D Perovskites
Tremblay, Marie-Hélène,Boyington, Allyson,Rigin, Sergei,Jiang, Jie,Bacsa, John,Al Kurdi, Khaled,Khrustalev, Victor N.,Pachter, Ruth,Timofeeva, Tatiana V.,Jui, Nathan,Barlow, Stephen,Marder, Seth R.
, p. 935 - 946 (2022/01/31)
((R(CH2)nNH3+ cations (R = aryl, substituted cyclohexyl; n = 1, 2) can form hybrid lead iodides that include both 2D layered perovskites of formula [R(CH2)nNH3]2PbI4 and 1D structures consisting of 1D wires of face-sharing PbI6 octahedra and having the formula [R(CH2)nNH3]PbI3 (face-sharing lead iodide chains, FSLICs). Using a series of such cations, we find that 1D FSLIC formation is favored when hydrogen bonding is possible between the ammonium moiety of one cation and a hydrogen-bond acceptor substituent of the same or another cation. A total of 16 new hybrid organic lead iodide crystal structures, 11 of which are FSLICs, are reported. The FSLIC structures can be further categorized according to the arrangement of neighboring wires. The optical properties of these materials are largely insensitive to the identity of the organic cations and to the resulting structural details. However, there is a correlation between the exciton energy and the pattern in which the wires are arranged relative to one another. Density functional theory calculations indicate that the dispersion at the top of the valence band varies depending on the relative wire arrangement.
Direct Access to Primary Amines from Alkenes by Selective Metal-Free Hydroamination
Du, Yi-Dan,Chen, Bi-Hong,Shu, Wei
supporting information, p. 9875 - 9880 (2021/03/29)
Direct and selective synthesis of primary amines from easily available precursors is attractive yet challenging. Herein, we report the rapid synthesis of primary amines from alkenes via metal-free regioselective hydroamination at room temperature. Ammonium carbonate was used as ammonia surrogate for the first time, allowing for efficient conversion of terminal and internal alkenes into linear, α-branched, and α-tertiary primary amines under mild conditions. This method provides a straightforward and powerful approach to a wide spectrum of advanced, highly functionalized primary amines which are of particular interest in pharmaceutical chemistry and other areas.
Palladium-Catalyzed C(sp2)-H Olefination of Free Primary and Secondary 2-Phenylethylamines: Access to Tetrahydroisoquinolines
Fan, Shuai,Ding, Yongzheng,Chen, Xiaoxi,Gao, Yuzhen,Fu, Lei,Li, Shangda,Li, Gang
, p. 13003 - 13012 (2019/10/11)
A rapid construction of THIQs by a Pd(II)-catalyzed C(sp2)-H olefination of free primary and secondary 2-phenylethylamines with high step- and atom-economy was reported. Notably, no substituent was required at the α-position to the amino group of the 2-phenylethylamines. The substrate scope was broad, and the reaction could also be applied to generate THIQs from the biologically active molecules such as the drug molecule baclofen and phenylalanine ester.
Catalytic Strategy for Regioselective Arylethylamine Synthesis
Boyington, Allyson J.,Seath, Ciaran P.,Zearfoss, Avery M.,Xu, Zihao,Jui, Nathan T.
supporting information, p. 4147 - 4153 (2019/03/07)
A mild, modular, and practical catalytic system for the synthesis of the highly privileged phenethylamine pharmacophore is reported. Using a unique combination of organic catalysts to promote the transfer of electrons and hydrogen atoms, this system performs direct hydroarylation of vinyl amine derivatives with a wide range of aryl halides (including aryl chlorides). This general and highly chemoselective protocol delivers a broad range of arylethylamine products with complete regiocontrol. The utility of this process is highlighted by its scalability and the modular synthesis of an array of bioactive small molecules.
Cobalt-Porphyrin-Catalysed Intramolecular Ring-Closing C?H Amination of Aliphatic Azides: A Nitrene-Radical Approach to Saturated Heterocycles
Kuijpers, Petrus F.,Tiekink, Martijn J.,Breukelaar, Willem B.,Broere, Dani?l L. J.,van Leest, Nicolaas P.,van der Vlugt, Jarl Ivar,Reek, Joost N. H.,de Bruin, Bas
supporting information, p. 7945 - 7952 (2017/06/19)
Cobalt-porphyrin-catalysed intramolecular ring-closing C?H bond amination enables direct synthesis of various N-heterocycles from aliphatic azides. Pyrrolidines, oxazolidines, imidazolidines, isoindolines and tetrahydroisoquinoline can be obtained in good to excellent yields in a single reaction step with an air- and moisture-stable catalyst. Kinetic studies of the reaction in combination with DFT calculations reveal a metallo-radical-type mechanism involving rate-limiting azide activation to form the key cobalt(III)-nitrene radical intermediate. A subsequent low barrier intramolecular hydrogen-atom transfer from a benzylic C?H bond to the nitrene-radical intermediate followed by a radical rebound step leads to formation of the desired N-heterocyclic ring products. Kinetic isotope competition experiments are in agreement with a radical-type C?H bond-activation step (intramolecular KIE=7), which occurs after the rate-limiting azide activation step. The use of di-tert-butyldicarbonate (Boc2O) significantly enhances the reaction rate by preventing competitive binding of the formed amine product. Under these conditions, the reaction shows clean first-order kinetics in both the [catalyst] and the [azide substrate], and is zero-order in [Boc2O]. Modest enantioselectivities (29–46 % ee in the temperature range of 100–80 °C) could be achieved in the ring closure of (4-azidobutyl)benzene using a new chiral cobalt-porphyrin catalyst equipped with four (1S)-(?)-camphanic-ester groups.
Catalytic Synthesis of N-Heterocycles via Direct C(sp3)-H Amination Using an Air-Stable Iron(III) Species with a Redox-Active Ligand
Bagh, Bidraha,Broere, Dani?l L. J.,Sinha, Vivek,Kuijpers, Petrus F.,Van Leest, Nicolaas P.,De Bruin, Bas,Demeshko, Serhiy,Siegler, Maxime A.,Van Der Vlugt, Jarl Ivar
supporting information, p. 5117 - 5124 (2017/05/04)
Coordination of FeCl3 to the redox-active pyridine-aminophenol ligand NNOH2 in the presence of base and under aerobic conditions generates FeCl2(NNOISQ) (1), featuring high-spin FeIII and an NNOISQ radical ligand. The complex has an overall S = 2 spin state, as deduced from experimental and computational data. The ligand-centered radical couples antiferromagnetically with the Fe center. Readily available, well-defined, and air-stable 1 catalyzes the challenging intramolecular direct C(sp3)-H amination of unactivated organic azides to generate a range of saturated N-heterocycles with the highest turnover number (TON) (1 mol% of 1, 12 h, TON = 62; 0.1 mol% of 1, 7 days, TON = 620) reported to date. The catalyst is easily recycled without noticeable loss of catalytic activity. A detailed kinetic study for C(sp3)-H amination of 1-azido-4-phenylbutane (S1) revealed zero order in the azide substrate and first order in both the catalyst and Boc2O. A cationic iron complex, generated from the neutral precatalyst upon reaction with Boc2O, is proposed as the catalytically active species.
Variation in the site of lithiation of 2-(2-methylphenyl)ethanamine derivatives
Smith, Keith,El-Hiti, Gamal A.,Alshammari, Mohammed B.
, p. 11210 - 11215 (2013/02/23)
Unexpectedly, lithiation of N′-(2-(2-methylphenyl)ethyl)-N,N- dimethylurea with 3 equiv of n-butyllithium in anhydrous THF at 0 C takes place on the nitrogen and on the CH2 next to the 2-methylphenyl ring (α-lithiation). The lithium reagent thus obtained reacts with various electrophiles to give the corresponding substituted derivatives in excellent yields. Similarly, lithiation of N-(2-(2-methylphenyl)ethyl)pivalamide under similar reaction conditions followed by reaction with benzophenone as a representative electrophile gave the corresponding α-substituted product in high yield. Surprisingly, no products resulting from lateral lithiation were observed under the conditions tried, which sharply contrasts with the reported results for lateral lithiation of tert-butyl (2-(2-methylphenyl)ethyl)carbamate.
THERAPEUTIC AGENT FOR CEREBRAL INFARCTION
-
, (2012/08/08)
The invention provides a therapeutic drug for ischemic stroke. The therapeutic drug has the formula (I) wherein each symbol is as defined herein, or a pharmacologically acceptable salt thereof, or a solvate thereof, as an active ingredient.
Mechanistic approach of the difference in non-enzymatic hydrolysis rate between the L and D enantiomers of no-carrier added 2-[18F] fluoromethyl-phenylalanine
Kersemans, Ken,Mertens, John,De Proft, Frank,Geerlings, Paul
experimental part, p. 80 - 85 (2011/10/30)
No-carrier added (n.c.a.) 2-[18F]fluoromethyl-l-phenylalanine was found to be very sensitive to hydrolysis in aqueous solutions. This problem was solved partially by the addition of calcium ions (0.04M), increasing the shelf-life to at least 6h. In this paper the defluorination reaction was studied in detail to elucidate its mechanism. Therefore, L and D enantiomers of 2-[18F]FMP and 4-[18F]FMP were synthesized, as well as 2-[18F]fluoromethyl-phenethylamine and 4-[18F] fluoromethyl-phenethylamine, both decarboxylated 'mimetic' molecules of the amino acid analogues. Radiosynthesis, using a customized Scintomics automatic synthesis hotboxthree module, resulted in a high overall yield and a radiochemical purity of >99%. The defluorination rates of all compounds were studied by HPLC. The L enantiomer of n.c.a 2-[18F]FMP defluorinated seven times faster than the D enantiomer and 2-[18F]fluoromethyl- phenethylamine. Both enantiomers of 4-[18F]FMP and 4-[ 18F]fluoromethyl-phenethylamine were stable. From these data, the reaction mechanism, involving two distinct intramolecular interactions, was derived. First, the interaction between the amine and the benzylic fluorine weakens the carbon-fluorine bond. Secondly, the formation of a second hydrogen bridge between the carboxyl group and one of the benzylic hydrogen atoms renders the fluorine atom even more susceptible to hydrolysis. The latter interaction induces an additional chiral center. The probability of its formation differs considerably between L and D enantiomers of n.c.a. 2-[18F]FMP, which explains the difference in hydrolysis rate. Copyright
Mechanistic approach of the difference in hydrolysis rate between the 2- and 4-isomers of no-carrier-added [18F]fluoromethyl-L-phenylalanine
Kersemans, Ken,Mertens, John,De Proft, Frank,Geerlings, Paul
body text, p. 220 - 223 (2012/05/20)
No-carrier-added (n.c.a.) 2-[18F]fluoromethyl-l-phenylalanine (2-[18F]FMP) was found to be very sensitive to hydrolysis in aqueous solutions. In this paper, the defluorination reaction was studied in detail to elucidate its mechanism
