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V. I. Boev - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of piperidine derivatives fused to a tetrahydrofuran ring
Russian Journal of Organic Chemistry, 2014Co-Authors: A. I. Moskalenko, V. I. BoevAbstract:Intramolecular nucleophilic opening of the oxirane ring in tert -butyl 6-(2-hydroxyethyl)-7-oxa-3-azabicyclo[4.1.0]heptane-3-carboxylate by the action of excess potassium hydroxide in 75% aqueous dimethyl sulfoxide at 110–120°C gave tert -butyl (3a R ,7a S )-3a-hydroxyhexahydrofuro[2,3- c ]pyridine-6(2 H )-carboxylate whose treatment with POCl_3 resulted in elimination of water molecule and tert -butoxycarbonyl Group with formation of 2,3,4,5,6,7-hexahydrofuro[2,3- c ]pyridine hydrochloride. The latter reacted with electrophiles (acetic anhydride, methanesulfonyl chloride, and benzaldehyde in combination with sodium triacetoxyhydridoborate) in the presence of triethylamine, yielding the corresponding N-substituted 2,3,4,5,6,7-hexahydrofuro[ 2,3- c ]pyridine derivatives.
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Heterocyclic ketones in the pfitzinger reaction
Russian Journal of General Chemistry, 2011Co-Authors: A. I. Moskalenko, A. V. Boeva, V. I. BoevAbstract:By the reaction of isatin with heterocyclic ketones ( N - tert -butoxycarbonyl derivatives of pyrrolidin-3-one, piperidin-4-one, piperidin-3-one, 1,2,3,4-tetrahydroquinolin-4-one, 8-azabicyclo[3.2.1]octan-3-one, tetrahydropyran-4-one, tetrahydrobenzopyran-4-one) in the presence of KOH (the Pfitzinger reaction) were synthesized quinoline-4-carboxylic acids [4,3]fused with the respective heterocycles. These acids were involved in the reactions with diazomethane and amines at the carboxy Group leading to methyl esters and amides, respectively. The esters obtained reacted with hydrazine hydrate affording the acid hydrazides, which entered in the condensation with benzaldehyde to form phenylhydrazones. The esters and amides containing N-tert -butoxycarbonyl fragment lost the tert -butoxycarbonyl Group easily to form the secondary amines dihydrochlorides, the [4,3]fused quinoline-4-carboxylic acid derivatives.
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Reactions of N-substituted 3-azabicyclo[3.3.1]nonan-9-ones with N,N-, N,S-, and N,O-binucleophiles
Russian Journal of Organic Chemistry, 2009Co-Authors: A. I. Moskalenko, V. I. BoevAbstract:Condensation of N-substituted 3-azabicyclo[3.3.1]nonan-9-ones with difunctional N,N-, N,S-, and N,O-centered nucleophiles ( o -phenylenediamine, 1,2-diphenylethane-1,2-diamine, 2-aminobenzenethiol, cysteine, 2-aminophenol, serine) gave the corresponding spiro heterocyclic compounds fused at the C^9 atom. Treatment of N-tert -butoxycarbonyl-substituted spiro compounds with anhydrous hydrogen chloride resulted in elimination of the tert -butoxycarbonyl Group with formation of spiro[3-azabicyclo[3.3.1]nonane-9,2′-azole] hydrochlorides.
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Reactions of 3-substituted 3-azabicyclo[3.3.1]nonan-9-ones with nitrogen-containing nucleophiles
Russian Journal of Organic Chemistry, 2009Co-Authors: A. I. Moskalenko, V. I. BoevAbstract:Condensation of 3-substituted 3-azabicyclo[3.3.1]nonan-9-ones with hydroxylamine and hydrazine hydrate gave the corresponding oximes, hydrazones, and azines. Reductive amination of the title compounds in the presence of sodium triacetoxyhydridoborate led to the formation of 3-substituted 3-azabicyclo[3.3.1]nonan-9-amines which were converted into the corresponding dihydrochlorides by treatment with dry hydrogen chloride. Treatment of 3- tert -butoxycarbonyl derivatives with HCl under analogous conditions was accompanied by elimination of the tert -butoxycarbonyl Group to produce 3-azabicyclo[3.3.1]nonan-9-amine dihydrochlorides.
A. I. Moskalenko - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of piperidine derivatives fused to a tetrahydrofuran ring
Russian Journal of Organic Chemistry, 2014Co-Authors: A. I. Moskalenko, V. I. BoevAbstract:Intramolecular nucleophilic opening of the oxirane ring in tert -butyl 6-(2-hydroxyethyl)-7-oxa-3-azabicyclo[4.1.0]heptane-3-carboxylate by the action of excess potassium hydroxide in 75% aqueous dimethyl sulfoxide at 110–120°C gave tert -butyl (3a R ,7a S )-3a-hydroxyhexahydrofuro[2,3- c ]pyridine-6(2 H )-carboxylate whose treatment with POCl_3 resulted in elimination of water molecule and tert -butoxycarbonyl Group with formation of 2,3,4,5,6,7-hexahydrofuro[2,3- c ]pyridine hydrochloride. The latter reacted with electrophiles (acetic anhydride, methanesulfonyl chloride, and benzaldehyde in combination with sodium triacetoxyhydridoborate) in the presence of triethylamine, yielding the corresponding N-substituted 2,3,4,5,6,7-hexahydrofuro[ 2,3- c ]pyridine derivatives.
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Heterocyclic ketones in the pfitzinger reaction
Russian Journal of General Chemistry, 2011Co-Authors: A. I. Moskalenko, A. V. Boeva, V. I. BoevAbstract:By the reaction of isatin with heterocyclic ketones ( N - tert -butoxycarbonyl derivatives of pyrrolidin-3-one, piperidin-4-one, piperidin-3-one, 1,2,3,4-tetrahydroquinolin-4-one, 8-azabicyclo[3.2.1]octan-3-one, tetrahydropyran-4-one, tetrahydrobenzopyran-4-one) in the presence of KOH (the Pfitzinger reaction) were synthesized quinoline-4-carboxylic acids [4,3]fused with the respective heterocycles. These acids were involved in the reactions with diazomethane and amines at the carboxy Group leading to methyl esters and amides, respectively. The esters obtained reacted with hydrazine hydrate affording the acid hydrazides, which entered in the condensation with benzaldehyde to form phenylhydrazones. The esters and amides containing N-tert -butoxycarbonyl fragment lost the tert -butoxycarbonyl Group easily to form the secondary amines dihydrochlorides, the [4,3]fused quinoline-4-carboxylic acid derivatives.
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Reactions of N-substituted 3-azabicyclo[3.3.1]nonan-9-ones with N,N-, N,S-, and N,O-binucleophiles
Russian Journal of Organic Chemistry, 2009Co-Authors: A. I. Moskalenko, V. I. BoevAbstract:Condensation of N-substituted 3-azabicyclo[3.3.1]nonan-9-ones with difunctional N,N-, N,S-, and N,O-centered nucleophiles ( o -phenylenediamine, 1,2-diphenylethane-1,2-diamine, 2-aminobenzenethiol, cysteine, 2-aminophenol, serine) gave the corresponding spiro heterocyclic compounds fused at the C^9 atom. Treatment of N-tert -butoxycarbonyl-substituted spiro compounds with anhydrous hydrogen chloride resulted in elimination of the tert -butoxycarbonyl Group with formation of spiro[3-azabicyclo[3.3.1]nonane-9,2′-azole] hydrochlorides.
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Reactions of 3-substituted 3-azabicyclo[3.3.1]nonan-9-ones with nitrogen-containing nucleophiles
Russian Journal of Organic Chemistry, 2009Co-Authors: A. I. Moskalenko, V. I. BoevAbstract:Condensation of 3-substituted 3-azabicyclo[3.3.1]nonan-9-ones with hydroxylamine and hydrazine hydrate gave the corresponding oximes, hydrazones, and azines. Reductive amination of the title compounds in the presence of sodium triacetoxyhydridoborate led to the formation of 3-substituted 3-azabicyclo[3.3.1]nonan-9-amines which were converted into the corresponding dihydrochlorides by treatment with dry hydrogen chloride. Treatment of 3- tert -butoxycarbonyl derivatives with HCl under analogous conditions was accompanied by elimination of the tert -butoxycarbonyl Group to produce 3-azabicyclo[3.3.1]nonan-9-amine dihydrochlorides.
G. H. Hakimelahi - One of the best experts on this subject based on the ideXlab platform.
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Ceric ammonium nitrate impregnated on silica gel in the removal of the Tert-Butoxycarbonyl Group
Arkivoc, 2002Co-Authors: Jih Ru Hwu, Moti L. Jain, Fu-yuan Tsai, A. Balakumar, G. H. Hakimelahi, Shwu-chen TsayAbstract:The Tert-Butoxycarbonyl Group was efficiently (80-99% yields) removed from an amino, hydroxy, or mercapto functionality in organic compounds by use of 0.20 equiv of Ce(NH4)2(NO3)6 in acetonitrile at reflux. Application of the solid-supported reagent involving the use of 0.20 equiv of Ce(NH4)2(NO3)6 impregnated on silica gel in toluene at reflux gave the deprotected products in 90-99% yields. These reactions likely proceed through an electron transfer process.
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Ceric ammonium nitrate in the deprotection of Tert-Butoxycarbonyl Group
Tetrahedron Letters, 1996Co-Authors: Jih Ru Hwu, Moti L. Jain, Tsay Shwu-chen, G. H. HakimelahiAbstract:Abstract The tert -butoxycarbonyl protecting Group for amines, alcohols, and thiols was removed efficiently (90–99% yields) by use of 0.20 equivalent of Ce(NH 4 ) 2 (NO 3 ) 6 in acetonitrile.
Jih Ru Hwu - One of the best experts on this subject based on the ideXlab platform.
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Ceric ammonium nitrate impregnated on silica gel in the removal of the Tert-Butoxycarbonyl Group
Arkivoc, 2002Co-Authors: Jih Ru Hwu, Moti L. Jain, Fu-yuan Tsai, A. Balakumar, G. H. Hakimelahi, Shwu-chen TsayAbstract:The Tert-Butoxycarbonyl Group was efficiently (80-99% yields) removed from an amino, hydroxy, or mercapto functionality in organic compounds by use of 0.20 equiv of Ce(NH4)2(NO3)6 in acetonitrile at reflux. Application of the solid-supported reagent involving the use of 0.20 equiv of Ce(NH4)2(NO3)6 impregnated on silica gel in toluene at reflux gave the deprotected products in 90-99% yields. These reactions likely proceed through an electron transfer process.
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Ceric ammonium nitrate in the deprotection of Tert-Butoxycarbonyl Group
Tetrahedron Letters, 1996Co-Authors: Jih Ru Hwu, Moti L. Jain, Tsay Shwu-chen, G. H. HakimelahiAbstract:Abstract The tert -butoxycarbonyl protecting Group for amines, alcohols, and thiols was removed efficiently (90–99% yields) by use of 0.20 equivalent of Ce(NH 4 ) 2 (NO 3 ) 6 in acetonitrile.
Hans Nohl - One of the best experts on this subject based on the ideXlab platform.
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Spin adduct formation from lipophilic EMPO-derived spin traps with various oxygen- and carbon-centered radicals.
Biochemical pharmacology, 2004Co-Authors: Klaus Stolze, Natascha Udilova, Thomas Rosenau, Andreas Hofinger, Hans NohlAbstract:Abstract Free radicals are involved in the onset of many diseases, therefore the availability of adequate spin traps is crucial to the identification and localization of free radical formation in biological systems. In recent studies several hydrophilic compounds of 2-ethoxycarbonyl-2-methyl-pyrroline- N- oxide (EMPO) have been found to form rather stable superoxide spin adducts with half-lives up to twenty minutes at physiological pH. This is a major improvement over DMPO ( t 1/2 = ca. 45 s), and even over DEPMPO ( t 1/2 = ca. 14 min), the best commercially available spin trap for the unambiguous detection of superoxide radicals. In order to allow the detection of superoxide and also other radicals in lipid environment a series of more lipophilic derivatives of EMPO was synthesized and their structure unambiguously characterized by 1 H and 13 C NMR spectroscopy. In this way, six different compounds with a n -butyl Group in position 5 and either an ethoxy- (EBPO), propoxy- (PBPO), iso -propoxy- ( i PBPO), butoxy- (BBPO), sec -butoxy- ( s BBPO) or tert -butoxycarbonyl Group ( t BBPO) in position 5 of the pyrroline ring were obtained and fully analytically characterized (NMR, IR). The stability of the superoxide adducts of all investigated spin traps were comparable with EMPO ( t 1/2 = ca. 8 min), except for the two compounds bearing an additional methyl Group in position 3 or 4 of the pyrroline ring, 5-butyl-5-ethoxycarbonyl-3-methyl-pyrroline- N -oxide (BEMPO-3) and 5-butyl-5-ethoxycarbonyl-4-methyl-pyrroline- N -oxide (BEMPO-4), of which the superoxide adducts were stable for more than 30 min. Spin adducts of other carbon- and oxygen-centered radicals were also investigated.