- Synthesis and in vitro antimycobacterial activity of novel n-arylpiperazines containing an ethane-1,2-diyl connecting chain
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Novel 1-(2-{3-/4-[(alkoxycarbonyl)amino]phenyl}-2-hydroxyethyl)-4-(2-fluorophenyl)-piperazin-1-ium chlorides (alkoxy = methoxy to butoxy; 8a-h) have been designed and synthesized through multistep reactions as a part of on-going research programme focused
- Gonec, Tomás,Malík, Ivan,Cs?llei, Jozef,Jampílek, Josef,Stolaríková, Jirina,Solovic, Ivan,Miku, Peter,Keltoová, Stanislava,Kollár, Peter,O'Mahony, Jim,Coffey, Aidan
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- Synthesis of 4-substituted-1,2-dihydroquinolines by means of gold-catalyzed intramolecular hydroarylation reaction of n-ethoxycarbonyl-n-propargylanilines
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An alternative Au(I)-catalyzed synthetic route to functionalized 1,2-dihydroquinolines is reported. This novel approach is based on the use of N-ethoxycarbonyl protected-Npropargylanilines as building blocks that rapidly undergo the IMHA reaction affording the 6-endo cyclization product in good to high yields. In the presence of N-ethoxycarbonyl-N-propargyl-metasubstituted anilines, the regiodivergent cyclization at the ortho-/para-position is achieved by the means of catalyst fine tuning.
- Arcadi, Antonio,Calcaterra, Andrea,Fabrizi, Giancarlo,Fochetti, Andrea,Goggiamani, Antonella,Iazzetti, Antonia,Marrone, Federico,Marsicano, Vincenzo,Mazzoccanti, Giulia,Serraiocco, Andrea
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supporting information
(2021/06/21)
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- Kinetics and mechanism of the reactions of anilines with ethyl S-aryl thiocarbonates
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The reactions of anilines with ethyl S-(2,4-dinitrophenyl) thiocarbonate (DNPTC) and ethyl S-(2,4,6-trinitrophenyl) thiocarbonate (TNPTC) are subjected to a kinetic study in aqueous solution at 25.0 °C and ionic strength 0.2 (KCl). The reactions are studied by following spectrophotometrically (400 nm) the release of the corresponding substituted benzenethiolate anion. Under aniline excess, pseudo-first-order rate coefficients (k(obsd)) are found. Plots of k(obsd) VS [N] (N is the free substituted aniline) are linear and pH independent, with slope k(N). The Bronsted-type plots (log k(N) vs pK(a) of anilinium ions) are linear, with slopes β = 0.9 for DNPTC, in agreement with a stepwise mechanism where the breakdown of a tetrahedral addition intermediate (T(±)) is rate determining, and β = 0.54 for TNPTC, consistent with a concerted mechanism. Consideration of the results for aminolysis from the present work and those from previous studies leads to the following conclusions. (i) The tetrahedral intermediate possessing a 2,4-dinitrobenzenethio group is more stable than that including the 2,4,6-trinitrobenzenethio group. (ii) The tetrahedral intermediate possessing the 2,4,6-trinitrobenzenethio group has no existence beyond the limit of a vibration period (concerted mechanism). (iii) Tetrahedral intermediates possessing anilino groups are less stable than those derived from pyridines but are more stable than the tetrahedral intermediates derived from secondary alicyclic amines. (iv) Anilines are more reactive toward the carbonyl group of methyl 2,4-dinitrophenyl carbonate than toward the carbonyl of DNPTC.
- Castro, Enrique A.,Leandro, Leonardo,Millan, Pablo,Santos, Jose G.
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p. 1953 - 1957
(2007/10/03)
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- Aryl and heteroaryl[[7-(3-disubstituted amino)phenyl]pyrazolo[1,5-a]pyrimidin-3-yl]methanones
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Novel aryl and heteroaryl[7-(3-substituted amino phenyl)-pyrazolo[1,5-a]pyrimidin-3-yl]methanones useful as anxiolytic, antiepileptic and sedative-hypnotic agents and as skeletal muscle relaxants, methods of using the novel compounds, compositions containing them and processes for this production.
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- Electrophilic Aromatic N-Substitution by Ethoxycarbonylnitrenium Ion generated from Ethyl Azidoformate in the Presence of Trifluoroacetic Acid
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Thermal reactions of ethyl azidoformate with aromatic compounds in the presence of trifluoroacetic acid (TFA) gave ethyl N-arylcarbamates.Toluene, nitrobenzene, or naphthalene was selectively attacked on the ortho- and para-positions, on the ortho- and meta-positions, or in the 1- and 2-positions, respectively.The yields were ca. twice as high as those for thermolysis ( a nitrene-azepine route) in the absence of TFA with the subsequent addition of TFA at room temperature.The positional selectivities for toluene and naphthalene were lower for the former thermolysis than for the latter.The reactivity of cyclohexane or toluene relative to benzene was greater in the latter thermolysis than the former.A Hammett plot with ρ - 1.7 was obtained for the formation of ethyl N-arylcarbamates in the former thermolysis in TFA-nitrobenzene (8:2 v/v); the value was more negative than that (-1.32) for the disappearance of substituted benzenes in the reaction with ethoxycarbonylnitrene.The results suggest that the thermolysis in the presence of TFA involves an electrophilic aromatic N-substitution by ethoxycarbonylnitrenium ion.
- Takeuchi, Hiroshi,Mastubara, Eiji
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p. 981 - 985
(2007/10/02)
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