Papers by Alexander Rozhenko
Russian Chemical Bulletin, Aug 1, 1991
Alkylation, by e-haloalkylphosphonates, of the Ni(II) complex of the Schiff base formed from glyc... more Alkylation, by e-haloalkylphosphonates, of the Ni(II) complex of the Schiff base formed from glycine and (S)-2-N-(Nl-benzylprolyl)-o-aminobenzophenone has been used for the asymmetric synthesis of (S)-2-amino-4-phosphonobutyric and (S)-2amino-5-phosphonovaleric acids.
ChemInform Abstract: Reaction of Methyl Trifluoropyruvate with Terminal Alkenes
ChemInform, 2010
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Asymmetric Synthesis of Organoelement Analogues of Natural Products; Part 12: General Method for the Asymmetric Synthesis of Fluorine-Containing Phenylalanines and α-Methyl(phenyl)alanines via Alkylation of the Chiral Nickel(II) Schiff's Base Complexes of Glycine and Alanine
Synthesis, 1993
Nickel(II) complexes of Schiffs bases derived from (S)-o-[(N-benzyl]prolyl)amino]benzophenone [N-... more Nickel(II) complexes of Schiffs bases derived from (S)-o-[(N-benzyl]prolyl)amino]benzophenone [N-(2-benzoylphenyl)-1-benzylpyrrolidine-2-carboxamide] (BBP) and glycine or alanine have been used for asymmetric synthesis of fluoro (S)-phenylalanines and (S)-α-methyl(phenyl)alanines. Large selectivity (>90%) is observed for the alkylation of both complexes.
Pharmaceutical Chemistry Journal, 1993
Alkylation, by e-haloalkylphosphonates, of the Ni(II) complex of the Schiff base formed from glyc... more Alkylation, by e-haloalkylphosphonates, of the Ni(II) complex of the Schiff base formed from glycine and (S)-2-N-(Nl-benzylprolyl)-o-aminobenzophenone has been used for the asymmetric synthesis of (S)-2-amino-4-phosphonobutyric and (S)-2amino-5-phosphonovaleric acids.
Energy and Environment Research, 2013
Based on nanoporous carbon electrodes electrochemical double layer capacitors (EDLC), otherwise k... more Based on nanoporous carbon electrodes electrochemical double layer capacitors (EDLC), otherwise known as supercapacitors or ultracapacitors, are currently widely used in various energy storage technologies, wherein the EDLC low internal resistance and long cycle life are at an advantage. It is still a good challenge to further reduce the internal resistance of EDLC since this can result in higher power density and higher efficiency of these promising power supply units. In this work it has been found that the EDLC internal resistance depends strongly on the electrolyte diffusion in the carbon electrode nanopores, and two techniques to measure the in-pore diffusion coefficients, namely, those based on spin-echo NMR or cyclic voltammetry with the use of porous rotating disc electrode are described. Cyclic voltammetry, impedance spectroscopy and transmission electron microscopy have also been used to select the best EDLC components. As a result, EDLC devices of very low internal resistance and high power density have been developed.
Heteroatom Chemistry, 2015
ABSTRACTCyclic zwitterionic phosphoranides 2a,b were found to be intermediate products in the rea... more ABSTRACTCyclic zwitterionic phosphoranides 2a,b were found to be intermediate products in the reaction of N,N‐dimethyl‐N′‐(aryl)formamidines with PBr3. The structure of phosphoranide 2a was determined by means of the X‐ray and quantum chemistry investigations. Mechanism of its formation was proposed based on Density functional theory (DFT) calculations. Reactions of 2 with amines and selenium yielded either C‐phosphorylated formamidines or benzazaphospholes. The first example of intramolecular heterocyclization of a pentavalent phosphorus derivative 15b into 3Н‐1,3‐benzazaphosphole has been demonstrated.
Applied Sciences, 2021
This work was conducted to study the chemical composition, antioxidant, antibacterial, and antifu... more This work was conducted to study the chemical composition, antioxidant, antibacterial, and antifungal activities of essential oil and hydrolat from Withania frutescens. The essential oil was extracted by hydrodistillation. The chemical characterization was performed using gas chromatography-mass spectrometry (GC/MS). The antioxidant activity was studied using four different assays (DPPH, TAC, FRAP, and β-carotene bleaching). The antibacterial activity test was carried out on multidrug-resistant bacteria including Gram-negative and Gram-positive strains. Antifungal activity was tested on Candida albicans and Saccharomyces cerevisiae. The yield of essential oil (EO) obtained by hydrodistillation of W. frutescens was 0.31% majorly composed of camphor, α-thujone, carvacrol, and thymol. Regarding the antioxidant activities, the concentration of the sample required to inhibit 50% of radicals (IC50) of EO and hydrolat were 14.031 ± 0.012 and 232.081 ± 3.047 µg/mL (DPPH), 4.618 ± 0.045 and ...
PLOS ONE, 2020
Anopheles darlingi is the main vector of malaria in Brazil, characterized by a high level of anth... more Anopheles darlingi is the main vector of malaria in Brazil, characterized by a high level of anthropophilia and endophagy. Imidacloprid, thiacloprid, and acetamiprid are the most widespread insecticides of the neonicotinoid group. However, they produce adverse effects on the non-target insects. Flupyradifurone has been marketed as an alternative to non-fluorinated neonicotinoids. Neonicotinoids containing trifluoroacethyl substituent reveal increased insecticidal activity due to higher hydrophobicity and metabolic stability. We synthesized novel neonicotinoid insecticides containing fluorinated acceptor groups and their interactions were estimated with the nicotinic acetylcholine receptor (nAChR) binding site by molecular docking studies, to evaluate their larvicidal activity against A. darlingi, and to assess their outdoor photodegradation behavior. New neonicotinoid analogues were prepared and characterized by NMR and mass-spectrometry. The synthesized molecules were modelled by time-dependent density functional theory and analyzed, their interaction with nAChR was investigated by molecular docking. Their insecticide activity was tested on Anopheles larvae collected in suburban area of Manaus, Brazil. Four new fluorinated neonicotinoid analogs were prepared and tested against 3 rd instars larvae of A. darlingi showing high larvicidal activity. Docking studies reveal binding modes of the synthesized compounds and suggest that their insecticidal potency is governed by specific interactions with the receptor binding site and enhanced lipophilicity. 2-Chloro-5-(2-trifluoromethyl-pyrrolidin-1ylmethyl)pyridine 5 showed fast degradation in water maintaining high larvicidal activity. All obtained substances possessed high larvicidal activity in low concentrations in 48 hours of exposure, compared to commercial flupyradifurone. Such activity is connected to a unique binding pattern of the synthesized compounds to insect's nAChR and to their enhanced bioavailability owing to introduction of fluorinated amino-moieties. Therefore, the compounds in question have a high potential for application as control agents for insects transmitting tropical diseases, and they will be less persistent in the environment.
Tetrahedron Letters, 2015
To create your abstract, type over the instructions in the template box below. Fonts or abstract ... more To create your abstract, type over the instructions in the template box below. Fonts or abstract dimensions should not be changed or altered. Stereoselective synthesis of six stereoisomers of inherently chiral methoxy-propoxybutoxy-methoxycarbonylmethoxy-tertbutylcalix[4]arene
On the Stability of Perfluoroalkyl-Substituted Singlet Carbenes: A Coupled-Cluster Quantum Chemical Study
The Journal of Physical Chemistry A, 2014
A series of trifluoromethyl-substituted carbenes R-C(:)-CF3 (R = NMe2, OMe, F, PMe2, P(NMe2)2, P(... more A series of trifluoromethyl-substituted carbenes R-C(:)-CF3 (R = NMe2, OMe, F, PMe2, P(NMe2)2, P(N(Pr-i)2)2, SMe, Cl); (dimethylamino)(perfluoroalkyl)carbenes Me2N-C(:)-R (R = CF3, C2F5, n-C3F7, i-C3F7, and t-C4F9) and symmetrically substituted carbenes R-C(:)-R (R = NMe2, OMe, F, PMe2, SMe, Cl) have been investigated by means of quantum chemistry methods. Different levels of approximation were used, including the CCSD(T) approach also known in quantum chemistry as the "golden standard", in combination with three different basis sets (TZVP, cc-pVDZ, cc-pVTZ). Relative stabilities of carbenes have been estimated using the differences between the singlet and triplet ground state energies (ΔEST) and energies of the hydrogenation reaction for the singlet and triplet ground states of the carbenes. The latter seem to correlate better with stability of carbenes than the ΔEST values. The (13)C NMR chemical shifts of the methylidene carbon indicate the more high-field chemical shift values in the known, isolable carbenes compared to the unstable ones. This is the first report on the expected chemical shifts in the highly unstable singlet carbenes. Using these criteria, some carbene structures from the studied series (as, for instance, Me2N-C(:)-CF3, Me2N-C(:)-C3F7-i) are proposed as good candidates for the experimental preparation.
Tetrahedron, 2011
A synthesis of 3H-1,3-benzazaphospholes starting from C-phosphorylated P(III) arylformamidines ha... more A synthesis of 3H-1,3-benzazaphospholes starting from C-phosphorylated P(III) arylformamidines has been developed. Electron-donating substituents were found to enhance markedly the rate of the cyclization, with substituents at the meta position having the greatest effect. A plausible mechanism of the cyclization was proposed based on DFT calculations.
2,3-Dihydro-1H-naphtho[1,8-de][1,3]diphosphinines
Phosphorus, Sulfur, and Silicon and the Related Elements, 2011
The reactions of 1,3-diphosphaphenalene 3 with sulfur, borane-tetrahydrofuran, and transition met... more The reactions of 1,3-diphosphaphenalene 3 with sulfur, borane-tetrahydrofuran, and transition metal carbonyls are reported.
An Unusual Intramolecular P-P Cyclization of The P-C-P System in Phosphaphenalenes
Phosphorus, Sulfur, and Silicon and the Related Elements, 2011
ABSTRACT An unusual P,P-disubstituted diphosphiranes was prepared and characterized by treatment ... more ABSTRACT An unusual P,P-disubstituted diphosphiranes was prepared and characterized by treatment of 1,8-bis[bis(di-alkylamino)phosphino]naphthalenes HCl followed by Me4NF.
Geometric and Electronic Structure of Carbocene, (C 5 R 5 ) 2 C, versus Silicocene, (C 5 R 5 ) 2 Si (R = H, Me)
Organometallics, 1999
... D 5 d structure was suggested for ferrocene (1; Chart 1) for the first time in 1952 1 conside... more ... D 5 d structure was suggested for ferrocene (1; Chart 1) for the first time in 1952 1 considerable interest has arisen in the ... In contrast to the highly symmetric structure adopted by ferrocene, structure determinations of the group 14 sandwich compounds 2 (M = Sn, Ge, Si) have ...
Journal of the American Chemical Society, 2000
The formation of a Fischer-type transition metal complex with a W(CO) 5 fragment is evaluated for... more The formation of a Fischer-type transition metal complex with a W(CO) 5 fragment is evaluated for the phosphanylcarbenes, Arduengo-type carbenes, and Bertrand-type carbenes by means of quantum chemical investigations at a density functional level with effective core potential methods. Accordingly, the stabilities of the complexes depend strongly on the substitution pattern of the carbenic unit. Amino-substituted carbenes as well as the Arduengo-type carbene form stable transition metal complexes. The stabilities of the complexes decrease for the phosphanylcarbenes and are at a minimum for the hitherto unknown transition metal complexes of the push-pull-type carbene of Bertrand. The matter is analyzed in terms of distortion energies required to bring the carbene units into the geometrical standard state for complexation with the transition metal fragment. The arguments evaluated for the phosphanylcarbenes should hold equally well for other carbenes substituted with electropositive ligands. For the mono-phosphanylcarbenes, η 1 as well as η 2 structures are investigated. For the diphosphanylcarbenes, a new structural type of metal complexes is predicted in which the transition metal fragment is strongly bound to a cyclic structural valence isomer of the carbene.
Journal of Organometallic Chemistry, 2001
The formation of coordination compounds of phosphanyl carbenes with a transition metal in a high ... more The formation of coordination compounds of phosphanyl carbenes with a transition metal in a high oxidation state (Schrock type) is evaluated by density functional theory. In the Schrock type carbene complexes the transition metal carbon bond possesses a multiple bond character. If one of the ligands at the carbene center possesses a leaving ability, e.g. as the diaminophosphenium unit, a facile distortion to a new type of an anionic metallaalkylidene donor-acceptor complex with a diaminophosphenium cation is predicted.
Donor–acceptor interactions with electrophilic terminal phosphinidene complexes
Journal of Organometallic Chemistry, 2002
ABSTRACT Donor–acceptor interactions of Lewis bases, such as amine, phosphine, cyanic acid and ph... more ABSTRACT Donor–acceptor interactions of Lewis bases, such as amine, phosphine, cyanic acid and phosphaalkine with various phosphinidene complexes carrying a W(CO)5 fragment are studied by means of density functional calculations. Accordingly, the donor interactions can be divided into two categories. In terms of energy an amine binds stronger than a phosphine to a phosphinidene, the resulting DoP bond is longer (NP) or equal (PP) with respect to a corresponding single bond. This tendency is also revealed in the corresponding transition metal complexes. In all cases the singlet-triplet energy separation values of the resulting donor-adducts are fairly small. A donor with a π-system, such as HCN yields a shorter NP bond, but the resulting donor-adduct is even less stable with respect to decomposition into a singlet PH complex and cyanic acid. Similar considerations with HCP reveal only a weak donor addition of this fragment to the parent PH complex but a facile rearrangement of the adduct to the diphosphirene transition metal complex. The diaminophosphino–PH possesses a singlet ground state, its corresponding transition metal complex reveals a fairly small singlet–triplet energy separation. It can be considered as a nucleophilic PH complex in contrast to the other homologues which reveal an electrophilic behaviour.
A kinetic study of guest displacement reactions on a host-guest complex with a photoswitchable calixarene
Journal of Mass Spectrometry, 2008
The displacement processes of several guests, incorporated in a calixarene host system, were inve... more The displacement processes of several guests, incorporated in a calixarene host system, were investigated in the gas phase by electrospray ionization-Fourier transform-ion cyclotron resonance (ESI-FT-ICR) mass spectrometry. The complexes resulting from a resorcin[4]arene host with ammonia and sec-butylamine guests were isolated in an ICR-cell, separately using both states of the photoswitch as well as two reference systems for the open and closed forms of the photoswitchable host. The isolated complexes were forced to exchange the guest by using methylamine, ethylamine and sec-butylamine, resulting in different reaction rates for all the measured systems. Especially, the reaction rates of both states of the photoswitch are dependent on the provided guest. Potential side effects like proton exchanges were examined by an H/D-exchange experiment. The results were investigated and supported by quantum chemical calculations (DFT).
Journal of Fluorine Chemistry, 2014
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Papers by Alexander Rozhenko