The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
L V Sherstyannikova - One of the best experts on this subject based on the ideXlab platform.
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new chiral diamines of the dioxolane series 4s 5s 2 2 dimethyl 4 5 bis diphenylaminomethyl 1 3 dioxolane and 4s 5s 2 2 dimethyl 4 5 bis methyl aminomethyl 1 3 dioxolane
Russian Journal of Organic Chemistry, 2002Co-Authors: B A Shainyan, L O Nindakova, M V Ustinov, N N Chipanina, L V SherstyannikovaAbstract:The reaction of sodium diphenylamide with 2,2-dimethyl-4,5-bis(tosyloxymethyl)-1,3-dioxolane gave (+)-(4S,5S)-2,2-dimethyl-4,5-bis(diphenylaminomethyl)-1,3-dioxolane, which was brought into complex formation with cobalt chloride. Treatment of 2,2-dimethyl-4,5-bis(tosyloxymethyl)-1,3-dioxolane with sodium N-methylanilide resulted in cleavage of the SAO bond in the p-toluenesulfonate moiety with formation of N-methyl-N-phenyl-p-toluenesulfonamide and 4,5-bis(hydroxymethyl)-2,2-dimethyl-1,3-dioxolane disodium salt. Diethyl (4R,5R)-2,2-dimethyl-1,3-dioxolane-4,5-dicarboxylate reacted with methylamine to give the corresponding dicarboxamide which was reduced with lithium aluminum hydride to (4S,5S)-2,2-dimethyl-4,5-bis(methylaminomethyl)-1,3-dioxolane having chiral carbon and nitrogen atoms.
Jiang Shengxiang - One of the best experts on this subject based on the ideXlab platform.
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ionic liquids as additives in high performance liquid chromatography analysis of amines and the interaction mechanism of ionic liquids
Analytica Chimica Acta, 2004Co-Authors: Xiao Xiaohua, Zhao Liang, Liu Xia, Jiang ShengxiangAbstract:Abstract As novel solvents, ionic liquids have many applications in synthesis, catalysis and analytical separation, i.e. extraction and chromatography separation. In this paper, some amines including benzidine, benzylamine, N-ethylaniline and N,N′-dimethylaniline are separated using ionic liquids as additives for the mobile phase in high performance liquid chromatography (HPLC). The effects of the length of alkyl chain or counterions on different ionic liquids and their concentrations on the separation of these analytes are performed. The differences between ionic liquids and tetrabutylammonium bromide (TBA) on the separation of o-, m-, p-phthalic acids are compared and the results show that ionic liquids are ion-pair reagents in essence, although their hydrophobicity and hydrogen bonding also play important roles.
Pieter L. Pohl - One of the best experts on this subject based on the ideXlab platform.
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host behaviour of related compounds tetrol and dmt in the presence of two different classes of aromatic guest compounds
Tetrahedron, 2018Co-Authors: Benita Barton, Sasha-lee Dorfling, Cedric W Mccleland, Lize Jager, Eric C. Hosten, Pieter L. PohlAbstract:Abstract The host potential of two closely-related compounds, TETROL [(+)-(2R,3R)-1,1–4,4-tetraphenylbutane-1,2,3,4-tetraol] and DMT [(−)-(2R,3R)-2,3-dimethoxy-1,1,4,4-tetraphenylbutane-1,4-diol], were compared when recrystallized from two different classes of guests, namely toluene, ethylbenzene, cumene and aniline, N-Methylaniline, N,N-dimethylaniline. TETROL formed complexes with only aniline and N-Methylaniline (host:guest ratios, 2:3 and 2:4), while DMT included all six guests with a consistent ratio (2:1). Aniline competition experiments showed that TETROL preferred aniline (67%), followed by N-methyl- (29%) and N,N-dimethyl- (4%) aniline; surprisingly, this order was exactly reversed for DMT [N,N-dimethylaniline (62%) > N-Methylaniline (32%) > aniline (6%)]. Crystal diffraction analyses revealed that TETROL formed stabilizing hydrogen bonds with guests, behaving as both donor and, for the first time, acceptor (in 2TETROL∙4N-Methylaniline). DMT did not form bonds of this type with any guests. Furthermore, the host packing was isostructural for all DMT complexes but was guest-dependent for TETROL. Thermal analyses showed that complex stabilities correlated precisely with the host preferences.
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host 2r 3r 2 3 dimethoxy 1 1 4 4 tetraphenylbutane 1 4 diol and guests aniline n methylaniline and n n dimethylaniline a selectivity study
Australian Journal of Chemistry, 2017Co-Authors: Benita Barton, Eric C. Hosten, Pieter L. PohlAbstract:The compound (–)-(2R,3R)-2,3-dimethoxy-1,1,4,4-tetraphenylbutane-1,4-diol (DMT) forms 2 : 1 host : guest complexes with aniline, N-Methylaniline, and N,N-dimethylaniline when recrystallized from these solvents. When the guests competed, as in binary and ternary mixtures, DMT proved to be remarkably selective for the alkylated guests, discriminating consistently against aniline. A host selectivity order of aniline << N-Methylaniline < N,N-dimethylaniline was observed. Results from single-crystal diffraction, Hirshfeld surface, and thermal analyses were used to explain the observed preference order. This investigation shows that using the realm of supramolecular chemistry may have future application in the separation of these anilines.
Sultan A Nasar - One of the best experts on this subject based on the ideXlab platform.
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effect of isocyanate structure on deblocking and cure reaction of n methylaniline blocked diisocyanates and polyisocyanates
European Polymer Journal, 2009Co-Authors: Govindarajan Sankar, Sultan A NasarAbstract:Abstract Two series of N-Methylaniline-blocked isocyanates based on monomeric diisocyanates such as 4,4′-methylene bis(phenyl isocyanate), toluene-2,4-diisocyanate, isophorone diisocyanate and 1,6-diisocyanato hexane and their NCO terminated polyurethane prepolymer (polyisocyanates) were prepared and characterized thoroughly by FTIR, 1H NMR, 13C NMR and EI-Mass spectroscopic methods. The blocking reaction of N-Methylaniline with aromatic isocyanates and aromatic polyisocyanates occur faster when compared to the aliphatic isocyanates. The deblocking reactions of blocked isocyanates were carried out under dynamic and isothermal conditions using hot-stage FTIR spectrophotometer. The dynamic method was used to determine the deblocking temperature, and the isothermal method was used to calculate kinetics and thermodynamics parameters. Cure reactions of blocked isocyanates with hydroxyl-terminated polybutadiene were also followed to establish the structure–property relationship of the N-Methylaniline-blocked isocyanates. The deblocking studies of blocked isocyanates reveal that the aromatic isocyanates undergo deblocking easily compared to aliphatic isocyanates. The rate of deblocking reaction of N-Methylaniline-blocked aromatic polyisocyanates was found to be higher compared to N-Methylaniline-blocked aromatic monomeric diisocyanate adducts. On the other hand, this trend was just reverse in the cure-reaction studies. The dissolution behavior of N-Methylaniline-blocked isocyanates in Terathane-2000, polypropylene glycol-2000, polycaprolactone diol-2000 and hydroxyl-terminated polybutadiene-2500 was also studied and found that all adducts are soluble in these polyols.
Robert P Hanzlik - One of the best experts on this subject based on the ideXlab platform.
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formation of cyclopropanone during cytochrome p450 catalyzed n dealkylation of a cyclopropylamine
Journal of the American Chemical Society, 2002Co-Authors: Christopher L Shaffer, Shawn Harriman, Yakov M Koen, Robert P HanzlikAbstract:The role of single electron transfer (SET) in P450-catalyzed N-dealkylation reactions has been studied using the probe substrates N-cyclopropyl-N-Methylaniline (2a) and N-(1‘-methylcyclopropyl)-N-Methylaniline (2b). In earlier work, we showed that SET oxidation of 2a by horseadish peroxidase leads exclusively to products arising via fragmentation of the cyclopropane ring [Shaffer, C. L.; Morton, M. D.; Hanzlik, R. P. J. Am. Chem. Soc. 2001, 123, 8502−8508]. In the present study, we found that liver microsomes from phenobarbital pretreated rats (which contain CYP2B1 as the predominant isozyme) oxidize [1‘-13C, 1‘-14C]-2a efficiently (80% consumption in 90 min). Disappearance of 2a follows first-order kinetics throughout, indicating a lack of P450 inactivation by 2a. HPLC examination of incubation mixtures revealed three UV-absorbing metabolites: N-Methylaniline (4), N-cyclopropylaniline (6a), and a metabolite (M1) tentatively identified as p-hydroxy-2a, in a 2:5:2 mole ratio, respectively. 2,4-Dinitrophen...
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n dealkylation of an n cyclopropylamine by horseradish peroxidase fate of the cyclopropyl group
Journal of the American Chemical Society, 2001Co-Authors: Christopher L Shaffer, Martha D Morton, Robert P HanzlikAbstract:Cyclopropylamines inactivate cytochrome P450 enzymes which catalyze their oxidative N-dealkylation. A key intermediate in both processes is postulated to be a highly reactive aminium cation radical formed by single electron transfer (SET) oxidation of the nitrogen center, but direct evidence for this has remained elusive. To address this deficiency and identify the fate of the cyclopropyl group lost upon N-dealkylation, we have investigated the oxidation of N-cyclopropyl-N-Methylaniline (3) by horseradish peroxidase, a well-known SET enzyme. For comparison, similar studies were carried out in parallel with N-isopropyl-N-Methylaniline (9) and N,N-dimethylaniline (8). Under standard peroxidatic conditions (HRP, H2O2, air), HRP oxidizes 8 completely to N-Methylaniline (4) plus formaldehyde within 15−30 min, whereas 9 is oxidized more slowly (<10% in 60 min) to produce only N-isopropylaniline (10) and formaldehyde (acetone and 4 are not formed). In contrast to results with 9, oxidation of 3 is complete in <60...
