14066-85-4Relevant academic research and scientific papers
The effect of organic cations on the electronic, optical and luminescence properties of 1D piperidinium, pyridinium, and 3-hydroxypyridinium lead trihalides
Bahnemann, D. W.,Emeline, A. V.,Kevorkyants, R.,Rozhkova, Yu. A.,Selivanov, N. I.
, p. 4390 - 4403 (2020)
We present a structural and optoelectronic study of 1D piperidinium, pyridinium, and 3-hydroxypyridinium lead trihalides. In contrast to the piperidinium and pyridinium species whose single inorganic chains [PbX31-]n are separated by organic cations, the 3-hydroxypyridinium compound is characterized by double inorganic chains. According to DFT the valence and conduction bands of the piperidinium lead trihalides are composed of occupied p-orbitals of the halogen anions and unoccupied p-orbitals of the Pb2+ cations. In contrast, the pyridinium species feature low-lying cationic energy levels formed from the cation's π?-orbitals. Thus, electronic transitions between the cationic energy levels and valence bands require less energy than valence to conduction band transitions in the case of piperidinium lead trihalides. The presence of an OH group in the pyridinium ring leads to a bathochromic shift of the cationic energy levels resulting in a decreased energy of transitions from the cationic energy levels to the valence band. Electronic transitions predicted by DFT are observable in experimental optical absorption and luminescence spectra. This study paves the way for creation of 1D perovskite-like structures with desired optoelectronic properties.
Sequential substitution/ring cleavage/addition reaction of 1-(cyclohex-1-enyl)-piperidine and -pyrrolidine with chloropyruvates for the efficient synthesis of substituted 4,5,6,7-tetrahydro-1H-indole derivatives
Mamedov, Vakhid A.,Hafizova, Elena A.,Zamaletdinova, Anastasiya I.,Rizvanov, Il'dar Kh.,Mirgorodskaya, Alla B.,Zakharova, Lucia Ya.,Latypov, Shamil K.,Sinyashin, Oleg G.
, p. 9143 - 9153 (2015/11/09)
Sequential substitution/ring cleavage/addition reaction of 1-(cyclohex-1-enyl)-piperidine and -pyrrolidine with chloropyruvates has been accomplished for the synthesis of various polysubstituted 4,5,6,7-tetrahydroindoles. This one-pot, general and highly regioselective method avoids harsh conditions and expensive catalysts. It proceeds with high atom-efficiency and shows a broad substrate scope and functional group tolerance, making it a highly practical approach for the preparation of various tetrahydroindole derivatives. A family of 17 tetrahydroindoles was synthesized in good yields, which is indicative of the general character of this reaction. 10 of the tetrahydroindole derivatives with various substituents were successfully transformed into the corresponding indoles. This methodology allows access to indoles bearing ω-halo- (mostly chloro-)butyl and pentyl substituents at the nitrogen atom (by variation of enamines) and at the C2, C3 positions (by variation of pyruvates, including bromoaryl and chloroalkyl derivatives). The reaction can be used in conjunction with enamine synthesis offering a practical three-component heteroannulation methodology to produce 4,5,6,7-tetrahydroindoles from cyclohexanone, pyrrolidine and arylchloropyruvates.
4-Hydroxyphenacyl Ammonium Salts: A Photoremovable Protecting Group for Amines in Aqueous Solutions
Bownik, Iwona,?ebej, Peter,Literák, Jaromír,Heger, Dominik,?imek, Zdeněk,Givens, Richard S.,Klán, Petr
, p. 9713 - 9721 (2015/10/12)
Irradiation of N-protected p-hydroxyphenacyl (pHP) ammonium caged derivatives at 313 nm releases primary and secondary amines or ammonia in nearly quantitative yields via the photo-Favorskii reaction when conducted in acidic or neutral aqueous buffered media. The reaction efficiencies are strongly dependent on the pH with the most efficient and highest yields obtained when the pH of the media maintains the ammonium and p-hydroxyl groups as their conjugate acids. For example, the overall quantum yields of simple secondary amines release are 0.5 at acidic pH from 3.9 to 6.6 dropping to 0.1 at neutral pH 7.0 and 0.01 at pH 8.4. Speciation studies provide an acid-base profile that helps define the scope and limitations of the reaction. When the pKa of the ammonium group is lower than that of the phenolic hydroxyl group, as is the case for the α-amino-protected amino acids, the more acidic ammonium ion deprotonates as the media pH is changed from acidic toward neutral or basic, thus diminishing the leaving group ability of the amino group. This, in turn, lowers the propensity for the photo-Favorskii rearrangement reaction to occur and opens the reaction pathway to alternative competing photoreduction process.
ALPHA7 NICOTINIC ACETYLCHOLINE RECEPTOR INHIBITORS
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Page/Page column 134, (2010/04/03)
The present invention provides compounds and compositions, methods of making them, and methods of using them to modulate α7 nicotinic acetylcholine receptors and/or to treat any of a variety of disorders, diseases, and conditions. Provided compounds can a
CATALYSIS IN THE FORMATION OF α-AMINO KETONES
Popov, A. F.,Anikeev, A. V.
, p. 939 - 944 (2007/10/02)
The kinetics of the reaction of α-halogenoacetophenones with piperidine and N-methylpiperidine in cyclohexane at 30 deg C were investigated.The autocatalytic nature of these reactions is due to the formation of catalitically active acidic products from degradation of the α-aminoacetophenone in the reaction system.The catalytic effect of additions of acetic acid and phenol on the rate of the reactions of α-halogenoacetophenone with piperidine and N-methylpiperidine is described quantitatively.Catalysis by acetic acid in the reactions of α-halogenoacetophenones with piperidine has a bifunctional mechanism.
EFFECT OF THE STRUCTURE OF AMINES ON RATE AND MECHANISM OF THEIR REACTIONS WITH 2-(β,β-DIBROMOVINYL)-5-NITROFURAN IN ACETONITRILE
Kravchenko, V. V.,Kotenko, A. A.,Popov, A. F.,Kostenko, L. I.,Vegh, D.,Kovac, J.
, p. 2140 - 2143 (2007/10/02)
The kinetics of the reaction of 2-(β,β-dibromovinyl)-5-nitrofuran with alkylamines of various types (primary, secondary, and tertiary) in acetonitrile at 55 deg C were studied.It was shown that enamines are formed quantitatively in the case of the reactions with secondary amines.At the same time the products from the reactions with primary amines are the corresponding amidines.Here the monosubstitution product is formed at the first stage, as in the case of the reactions with secondary amines, and rearranges to the imidoyl halide with subsequent substitution of the halogen atom at the imidoyl carbon atom.A quantitative assessment is made of the effect of the structure of the enamine on the rate of the processes.
EFFECT OF THE NATURE OF THE LEAVING GROUP IN REACTIONS OF 2-X-N-ETHYLPYRIDINIUM SALTS WITH AMINES IN ACETONITRILE
Titskii, G. D.,Mitchenko, E. S.
, p. 1949 - 1954 (2007/10/02)
The rate-determining stage in the nucleophilic substitution reactions of 2-X-N-ethylpyridinium salts with piperidine in acetonitrile changes, depending on the nature of the leaving group X.In the case where X = Hlg the controlling stage is the formation of the C-N bond.When X = 4-NO2C6H4O3, 3,4-(NO2)2C6H3O, and 2,6-(NO2)2C6H3O, nucleophilic substitution at the carbon atom is controlled by cleavage of the C-X bond.Nucleophilic substitution at a carbon atom of the benzene ring predominates in the reaction of 2-(2,4-dinitrophenoxy)-N-ethylpyridinium salt with piperidine.
KINETICS AND MECHANISM OF REACTION OF AMINES WITH β-BROMOPROPIOPHENONE
Popov, A. F.,Piskunova, Z.,Matvienko, V. N.
, p. 1299 - 1302 (2007/10/02)
The reaction of β-bromopropiophenone with different amines in acetonitrile at 25 deg C was studied.It was found that in the case of primary and secondary amines, the end products of the reaction are β-aminopropiophenones, which form via the intermediate phenyl vinyl ketone.In the case of tertiary amines, the reaction ends at the stage of the formation of phenyl vinyl ketone.The reactivity of the amines in the formation of phenyl vinyl ketone is preferentially determined by their basicity.
KINETICS OF THE REACTIONS OF 2-HALOGENOPYRIDINIUM SALTS WITH PRIMARY AND SECONDARY AMINES IN ACETONITRILE
Litvinenko, L. M.,Titskii, G. D.,Mitchenko, E. S.
, p. 1731 - 1736 (2007/10/02)
The kinetics of the reactions of 2-halogeno-N-alkylpyridinium salts with primary and secondary aliphatic amines in acetonitrile at 25 deg C were investigated.The reactions obey second-order relationships.In the reaction of 2-bromo-N-ethylpyridinium bromide with aliphatic amines the effect of electronic and steric factors on the reactivity of the amines was examined.
Palladium-Catalyzed Cyclizations of Bromodialkenyl Ethers and Amines
Shi, L.,Narula, C. K.,Mak, K. T.,Kao, L.,Xu, Y.,Heck, R. F.
, p. 3894 - 3900 (2007/10/02)
A variety of vinylic bromoalkenyl alkenyl ethers were reacted with piperidine and a palladium acetate-tri-o-tolylphosphine catalyst.Intramolecular vinylic substitution occurred in many cases.Five-membered rings formed most easily, followed by six and then
