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Yu. V. Shklyaev - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of Podands of the 3,4-dihydroisoquinoline series
Russian Journal of Organic Chemistry, 2014Co-Authors: Yu. V. Shklyaev, T. S. VshivkovaAbstract:Podands containing 3,4-dihydroisoquinoline fragments were synthesized by reactions of 1,1′-{ethane-1,2-diylbis[oxy(3-methoxybenzene-4,1-diyl)]}bis(2-Methylpropan-1-ol) and 1-(2-ethoxyethoxy)-2-methoxy-4-(2-Methylprop-1-en-1-yl)benzene with ethyl cyanoacetate and Methyl Thiocyanate in concentrated sulfuric acid. Likewise, 1-substituted 3,4-dihydroisoquinolines having a crown ether fragment were obtained from 4-acetylbenzo-12-crown-4.
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Polyalkoxybenzenes from plant material 6. Synthesis of 3-Methyl-3,4-dihydroisoquinolines from apiol
Russian Chemical Bulletin, 2012Co-Authors: Yu. V. Shklyaev, S. I. Firgang, A. A. Smolyak, L. D. KonyushkinAbstract:A number of dihydroisoquinolines were synthesized by the reaction of apiol, a natural allylbenzene, with nitriles. When Methyl Thiocyanate was used as the nitrile component, the formation of 2-azaspiro[4.5]deca-1,6,9-trien-8-one derivatives, the spiroheterocyclization product, was also observed.
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Retropinacol Rearrangement in the Synthesis of 3,3,4-TriMethyl- 2-azaspiro(4.5)deca-1,6,9-trien-8-one Derivatives
Russian Journal of Organic Chemistry, 2011Co-Authors: Yu. V. Shklyaev, O. G. Stryapunina, O. A. MaiorovaAbstract:In the recent years 2-azaspiro[4.5]deca-1,6,9-trien8-one derivatives have attracted researchers’ attention due to their biological activity [1, 2]. These compounds may be synthesized in different ways; for example, 7-methoxy-2-Methyl-2-azaspiro[4.5]deca-6,9diene-3,8-dione was obtained by heating 2-[(3,4-dimethoxybenzyl)(Methyl)amino]-2-oxoethyldiazonium salt for a short time [3]. The simplest procedure for the synthesis of 2-azaspiro[4.5]deca-1,6,9-trien-8-one derivatives is based on three-component condensation of substituted anisole with isobutyraldehyde and nitrile in concentrated sulfuric acid [4–7]. Generation of carbenium ion as key intermediate in the Ritter heterocyclization is also possible via retropinacol rearrangement of the corresponding alcohol [8]; in this way, 3,3,4-triMethyl-3,4-dihydroisoquinoline derivatives can be obtained. In fact, by reaction of anisole (I) or 1-methoxynaphthalene (II) with pivalaldehyde and nitriles (such as Methyl Thiocyanate and Methyl and ethyl cyanoacetates) under the conditions described in [8] we obtained the corresponding 2-azaspiro[4.5]deca-1,6,9-trien-8-one derivatives III–VIII in 28–49% yield (Scheme 1). The reaction was accompanied by concurrent Danilov rearrangement [9], so that 2 equiv of pivalaldehyde was necessary.
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Synthesis of 1-substituted (R,S)-8-(2-methoxy-5-Methylphenyl)-3,3,9-triMethyl-2-azaspiro[4.5]deca-1,7-dien-6-ones
Russian Chemical Bulletin, 2002Co-Authors: Yu. V. Shklyaev, Yu. V. Nifontov, A. S. Shashkov, S. I. FirgangAbstract:Reactions between p -Methylanisole, isobutyraldehyde, and nitriles (acetonitrile, Methyl Thiocyanate, or ethyl cyanoacetate) in conc. H_2SO_4 yield 1-substituted ( R , S )-8-(2-methoxy-5-Methylphenyl)-3,3,9-triMethyl-2-azaspiro[4.5]deca-1,7-dien-6-ones.
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Synthesis and Rearrangement of 1-Substituted 3,3,7-TriMethyl-2-azaspiro[4.5]deca-1,6,9-trien-8-ones
Russian Journal of Organic Chemistry, 2002Co-Authors: Yu. V. Nifontov, Vladimir A. Glushkov, O. G. Ausheva, Yu. V. ShklyaevAbstract:We previously synthesized 3,3-diMethyl-1-Methylthio-2-azaspiro[4.5]deca-1,6,9-trien-8-one by threecomponent condensation of anisole, 1,2-epoxy-2Methylpropane, and nitriles in the presence of concentrated sulfuric acid [1]. An analogous result was obtained in the reaction of anisole with isobutyraldehyde and nitriles [2]. Taking into account that the product composition strongly depends on the nature and position of substituents in the aromatic ring [3], we thought it reasonable to examine the same transformation of anisole homologs, in particular of Methyl o-tolyl ether. We have fount that introduction of a Methyl group into the ortho-position of anisole does not change the reaction direction. Addition of an equimolar mixture of Methyl o-tolyl ether, isobutyraldehyde, and Methyl Thiocyanate to concentrated sulfuric acid at 035oC, followed by dilution of the reaction mixture with cold water and neutralization of the aqueous phase with ammonium carbonate, leads to formation of 3,3,7-triMethyl-1-Methylthio-2-azaspiro[4.5]deca1,6,9-trien-8-one (IIa) in 67% yield. The isolated product was a single enantiomer whose configuration was not determined. The presence of an asymmetric spiro-carbon atom in molecule IIa is confirmed by the H NMR spectrum, where splitting of signals from diastereotopic protons of the CH2 and 3-CH3 groups is observed. Spiro compounds IIb and IIc, formed in the reactions with ethyl cyanoacetate and cyanoacetamide, undergo dienone3phenol rearrangement during isolation. As a result, amides III and IV were obtained. The relatively ready hydrolysis of structurally related ____________ * This study was financially supported by the Russian Foundation for Basic Research (project no. 01-03-96 479). spiro compounds with carbonyl-containing groups (derived from anisole) was noted by us previously [4]. 3,3,7-TriMethyl-1-Methylthio-2-azaspiro[4.5]deca-1,6,9-trien-8-one (IIa). A mixture of 12.2 g (0.1 mol) of Methyl o-tolyl ether, 7.2 g (0.1 mol) of isobutyraldehyde, and 7.3 g (0.1 mol) of Methyl Thiocyanate was added dropwise over a period of 15320 min to 50 ml of 96% sulfuric acid stirred at 035oC. The mixture was stirred for 30 min, poured into 300 ml of water, and extracted with 50 ml of toluene. The aqueous phase was separated and neutralized with (NH4)2CO3 to pH 839. The precipitate was filtered off, washed with water, dried, and recrystallized twice from methanol. Yield 15.75 g (67%), mp 63364oC. IR spectrum, n, cm: 1660 (CIO), 1630 (CIC), 1605 (CIN), 1580. H NMR spectrum, d, ppm: 1.36 s and 1.39 s (6H, 3-CH3), 1.82 s (3H, 7-CH3), 2.18 s and 2.20 s (2H, 4-H),
Patrik Spaněl - One of the best experts on this subject based on the ideXlab platform.
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Variability in the concentrations of volatile metabolites emitted by genotypically different strains of Pseudomonas aeruginosa
Journal of Applied Microbiology, 2012Co-Authors: Violetta Shestivska, Kristýna Sovova, Kseniya Dryahina, Patrik Spaněl, David Smith, M. Musílek, Alexandr NemecAbstract:Aims To characterize the volatile metabolites produced by genotypically diverse strains of Pseudomonas aeruginosa in order to evaluate their potential for use as biomarkers of lung infection in noninvasive breath analysis. Methods and Results Volatile organic compounds (VOCs) emitted from 36 clinical strains of Ps. aeruginosa (belonging to different multilocus sequence types) cultured in liquid and on solid media were analysed by gas chromatography mass spectrometry (GC-MS) and selected ion flow tube mass spectrometry (SIFT-MS). Several previously identified VOCs were detected, including ethanol, acetone, 2-butanone, 2-pentanone, isoprene, aminoacetophenone, diMethyl sulphide, diMethyl disulphide, diMethyl trisulphide and Methyl Thiocyanate. Additionally, significant production of 3-Methyl-butanone, acetophenone, Methylthioacetate and Methyl thiobutanoate was observed for the first time in this study. SIFT-MS quantifications of VOCs showed high variability between genotypically distinct strains. Conclusions The data obtained indicate that the production rates of the volatile biomarkers of Ps. aeruginosa vary by two orders of magnitude between different strains cultured under the same conditions. Similar variability was observed for both liquid and solid media. Significance and Impact of the Study Inter-strain genotypic variability strongly influences the concentrations of the volatile biomarkers from Ps. aeruginosa. A group of several biomarkers quantified in real time in exhaled breath may thus provide a more valuable indicator of the course of pulmonary infections compared to a single biomarker.
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quantification of Methyl Thiocyanate in the headspace of pseudomonas aeruginosa cultures and in the breath of cystic fibrosis patients by selected ion flow tube mass spectrometry
Rapid Communications in Mass Spectrometry, 2011Co-Authors: Violetta Shestivska, Alexandr Nemec, Pavel Dřevinek, Kristýna Sovova, Kseniya Dryahina, Patrik SpanělAbstract:Infection by Pseudomonas aeruginosa (PA) is a major cause of morbidity and mortality in patients with cystic fibrosis (CF). Breath analysis could potentially be a useful diagnostic of such infection, and analyses of volatile organic compounds (VOCs) emitted from PA cultures are an important part of the search for volatile breath markers of PA lung infection. Our pilot experiments using solid-phase microextraction, SPME and gas chromatography/mass spectrometric (GC/MS) analyses of volatile compounds produced by PA strains indicated a clear presence of Methyl Thiocyanate. This provided a motivation to develop a method for real-time online quantification of this compound by selected ion flow tube mass spectrometry, SIFT-MS. The kinetics of reactions of H3O+, NO+ and O2+• with Methyl Thiocyanate at 300 K were characterized and the characteristic product ions determined (proton transfer for H3O+, rate constant 4.6 × 10–9 cm3 s–1; association for NO+, 1.7 × 10–9 cm3 s–1 and nondissociative charge transfer for O2+•, 4.3 × 10–9 cm3 s–1). The kinetics library was extended by a new entry for Methyl Thiocyanate accounting for overlaps with isotopologues of hydrated hydronium ions. Solubility of Methyl Thiocyanate in water (Henry's law constant) was determined using standard reference solutions and the linearity and limits of detection of both SIFT-MS and SPME-GC/MS methods were characterized. Thirty-six strains of PA with distinct genotype were cultivated under identical conditions and 28 of them (all also producing HCN) were found to release Methyl Thiocyanate in headspace concentrations greater than 6 parts per billion by volume (ppbv). SIFT-MS was also used to analyze the breath of 28 children with CF and the concentrations of Methyl Thiocyanate were found to be in the range 2–21 ppbv (median 7 ppbv). Copyright © 2011 John Wiley & Sons, Ltd.
Witold Danikiewicz - One of the best experts on this subject based on the ideXlab platform.
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gas phase reactions of Methyl Thiocyanate with aliphatic carbanions a mass spectrometry and computational study
Rapid Communications in Mass Spectrometry, 2016Co-Authors: Barbara Repec, Kacper Blaziak, Witold DanikiewiczAbstract:Rationale Methyl Thiocyanate, like other organic Thiocyanates, is a molecule with many electrophilic reactive sites and it has many synthetic applications. For better understanding of the intrinsic reactivity of alkyl Thiocyanates against nucleophiles it was important to study gas-phase reactions of Methyl Thiocyanate with carbanions differing by structure and proton affinity values. Methods All experiments were performed using a modified API 365 triple quadrupole mass spectrometer equipped with a TurboIonSpray electrospray ionization (ESI) source. Carbanions were generated in the ESI source by decarboxylation of the respective carboxylic acid anions. Methyl Thiocyanate was delivered as a vapor with nitrogen used as a collision gas to the collision cell where the reactions take place. Results Mass spectra recorded for the gas-phase reactions of five aliphatic carbanions with Methyl Thiocyanate showed a variety of product ions formed via different reaction mechanisms, depending on the structure and proton affinity of the carbanion. The pathways considered are: SN2 nucleophilic substitution, cyanophilic reaction, thiophilic reaction and proton transfer, followed in some instances by subsequent transformations. The proposed reaction pathways are supported by density functional theory (DFT) calculations. Conclusions Our preliminary experiments showed that mass spectrometry together with quantum chemical calculations is a good tool for studying gas-phase reactions of alkyl Thiocyanates with carbanions. In the gas phase all four theoretically possible products can be observed and their formation can be rationalized by the results of the modelling of the reaction energy profiles. Copyright © 2016 John Wiley & Sons, Ltd.
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Gas‐phase reactions of Methyl Thiocyanate with aliphatic carbanions – A mass spectrometry and computational study
Rapid Communications in Mass Spectrometry, 2016Co-Authors: Barbara Repeć, Kacper Błaziak, Witold DanikiewiczAbstract:Rationale Methyl Thiocyanate, like other organic Thiocyanates, is a molecule with many electrophilic reactive sites and it has many synthetic applications. For better understanding of the intrinsic reactivity of alkyl Thiocyanates against nucleophiles it was important to study gas-phase reactions of Methyl Thiocyanate with carbanions differing by structure and proton affinity values. Methods All experiments were performed using a modified API 365 triple quadrupole mass spectrometer equipped with a TurboIonSpray electrospray ionization (ESI) source. Carbanions were generated in the ESI source by decarboxylation of the respective carboxylic acid anions. Methyl Thiocyanate was delivered as a vapor with nitrogen used as a collision gas to the collision cell where the reactions take place. Results Mass spectra recorded for the gas-phase reactions of five aliphatic carbanions with Methyl Thiocyanate showed a variety of product ions formed via different reaction mechanisms, depending on the structure and proton affinity of the carbanion. The pathways considered are: SN2 nucleophilic substitution, cyanophilic reaction, thiophilic reaction and proton transfer, followed in some instances by subsequent transformations. The proposed reaction pathways are supported by density functional theory (DFT) calculations. Conclusions Our preliminary experiments showed that mass spectrometry together with quantum chemical calculations is a good tool for studying gas-phase reactions of alkyl Thiocyanates with carbanions. In the gas phase all four theoretically possible products can be observed and their formation can be rationalized by the results of the modelling of the reaction energy profiles. Copyright © 2016 John Wiley & Sons, Ltd.
Violetta Shestivska - One of the best experts on this subject based on the ideXlab platform.
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Variability in the concentrations of volatile metabolites emitted by genotypically different strains of Pseudomonas aeruginosa
Journal of Applied Microbiology, 2012Co-Authors: Violetta Shestivska, Kristýna Sovova, Kseniya Dryahina, Patrik Spaněl, David Smith, M. Musílek, Alexandr NemecAbstract:Aims To characterize the volatile metabolites produced by genotypically diverse strains of Pseudomonas aeruginosa in order to evaluate their potential for use as biomarkers of lung infection in noninvasive breath analysis. Methods and Results Volatile organic compounds (VOCs) emitted from 36 clinical strains of Ps. aeruginosa (belonging to different multilocus sequence types) cultured in liquid and on solid media were analysed by gas chromatography mass spectrometry (GC-MS) and selected ion flow tube mass spectrometry (SIFT-MS). Several previously identified VOCs were detected, including ethanol, acetone, 2-butanone, 2-pentanone, isoprene, aminoacetophenone, diMethyl sulphide, diMethyl disulphide, diMethyl trisulphide and Methyl Thiocyanate. Additionally, significant production of 3-Methyl-butanone, acetophenone, Methylthioacetate and Methyl thiobutanoate was observed for the first time in this study. SIFT-MS quantifications of VOCs showed high variability between genotypically distinct strains. Conclusions The data obtained indicate that the production rates of the volatile biomarkers of Ps. aeruginosa vary by two orders of magnitude between different strains cultured under the same conditions. Similar variability was observed for both liquid and solid media. Significance and Impact of the Study Inter-strain genotypic variability strongly influences the concentrations of the volatile biomarkers from Ps. aeruginosa. A group of several biomarkers quantified in real time in exhaled breath may thus provide a more valuable indicator of the course of pulmonary infections compared to a single biomarker.
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quantification of Methyl Thiocyanate in the headspace of pseudomonas aeruginosa cultures and in the breath of cystic fibrosis patients by selected ion flow tube mass spectrometry
Analytical Abstracts, 2012Co-Authors: Violetta Shestivska, Alexandr Nemec, Kristýna Sovova, Kseniya Dryahina, P Drevinek, Patrik SpanelAbstract:Infection by Pseudomonas aeruginosa (PA) is a major cause of morbidity and mortality in patients with cystic fibrosis (CF). Breath analysis could potentially be a useful diagnostic of such infection, and analyses of volatile organic compounds (VOCs) emitted from PA cultures are an important part of the search for volatile breath markers of PA lung infection. Our pilot experiments using solid-phase microextraction, SPME and gas chromatography/mass spectrometric (GC/MS) analyses of volatile compounds produced by PA strains indicated a clear presence of Methyl Thiocyanate. This provided a motivation to develop a method for real-time online quantification of this compound by selected ion flow tube mass spectrometry, SIFT-MS. The kinetics of reactions of H3O+, NO+ and O2 +• with Methyl Thiocyanate at 300 K were characterized and the characteristic product ions determined (proton transfer for H3O+, rate constant 4.6 × 10–9 cm3 s–1; association for NO+, 1.7 × 10–9 cm3 s–1 and nondissociative charge transfer for O2 +•, 4.3 × 10–9 cm3 s–1). The kinetics library was extended by a new entry for Methyl Thiocyanate accounting for overlaps with isotopologues of hydrated hydronium ions. Solubility of Methyl Thiocyanate in water (Henry's law constant) was determined using standard reference solutions and the linearity and limits of detection of both SIFT-MS and SPME-GC/MS methods were characterized. Thirty-six strains of PA with distinct genotype were cultivated under identical conditions and 28 of them (all also producing HCN) were found to release Methyl Thiocyanate in headspace concentrations greater than 6 parts per billion by volume (ppbv). SIFT-MS was also used to analyze the breath of 28 children with CF and the concentrations of Methyl Thiocyanate were found to be in the range 2-21 ppbv (median 7 ppbv).
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quantification of Methyl Thiocyanate in the headspace of pseudomonas aeruginosa cultures and in the breath of cystic fibrosis patients by selected ion flow tube mass spectrometry
Rapid Communications in Mass Spectrometry, 2011Co-Authors: Violetta Shestivska, Alexandr Nemec, Pavel Dřevinek, Kristýna Sovova, Kseniya Dryahina, Patrik SpanělAbstract:Infection by Pseudomonas aeruginosa (PA) is a major cause of morbidity and mortality in patients with cystic fibrosis (CF). Breath analysis could potentially be a useful diagnostic of such infection, and analyses of volatile organic compounds (VOCs) emitted from PA cultures are an important part of the search for volatile breath markers of PA lung infection. Our pilot experiments using solid-phase microextraction, SPME and gas chromatography/mass spectrometric (GC/MS) analyses of volatile compounds produced by PA strains indicated a clear presence of Methyl Thiocyanate. This provided a motivation to develop a method for real-time online quantification of this compound by selected ion flow tube mass spectrometry, SIFT-MS. The kinetics of reactions of H3O+, NO+ and O2+• with Methyl Thiocyanate at 300 K were characterized and the characteristic product ions determined (proton transfer for H3O+, rate constant 4.6 × 10–9 cm3 s–1; association for NO+, 1.7 × 10–9 cm3 s–1 and nondissociative charge transfer for O2+•, 4.3 × 10–9 cm3 s–1). The kinetics library was extended by a new entry for Methyl Thiocyanate accounting for overlaps with isotopologues of hydrated hydronium ions. Solubility of Methyl Thiocyanate in water (Henry's law constant) was determined using standard reference solutions and the linearity and limits of detection of both SIFT-MS and SPME-GC/MS methods were characterized. Thirty-six strains of PA with distinct genotype were cultivated under identical conditions and 28 of them (all also producing HCN) were found to release Methyl Thiocyanate in headspace concentrations greater than 6 parts per billion by volume (ppbv). SIFT-MS was also used to analyze the breath of 28 children with CF and the concentrations of Methyl Thiocyanate were found to be in the range 2–21 ppbv (median 7 ppbv). Copyright © 2011 John Wiley & Sons, Ltd.
O. A. Maiorova - One of the best experts on this subject based on the ideXlab platform.
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Retropinacol Rearrangement in the Synthesis of 3,3,4-TriMethyl- 2-azaspiro(4.5)deca-1,6,9-trien-8-one Derivatives
Russian Journal of Organic Chemistry, 2011Co-Authors: Yu. V. Shklyaev, O. G. Stryapunina, O. A. MaiorovaAbstract:In the recent years 2-azaspiro[4.5]deca-1,6,9-trien8-one derivatives have attracted researchers’ attention due to their biological activity [1, 2]. These compounds may be synthesized in different ways; for example, 7-methoxy-2-Methyl-2-azaspiro[4.5]deca-6,9diene-3,8-dione was obtained by heating 2-[(3,4-dimethoxybenzyl)(Methyl)amino]-2-oxoethyldiazonium salt for a short time [3]. The simplest procedure for the synthesis of 2-azaspiro[4.5]deca-1,6,9-trien-8-one derivatives is based on three-component condensation of substituted anisole with isobutyraldehyde and nitrile in concentrated sulfuric acid [4–7]. Generation of carbenium ion as key intermediate in the Ritter heterocyclization is also possible via retropinacol rearrangement of the corresponding alcohol [8]; in this way, 3,3,4-triMethyl-3,4-dihydroisoquinoline derivatives can be obtained. In fact, by reaction of anisole (I) or 1-methoxynaphthalene (II) with pivalaldehyde and nitriles (such as Methyl Thiocyanate and Methyl and ethyl cyanoacetates) under the conditions described in [8] we obtained the corresponding 2-azaspiro[4.5]deca-1,6,9-trien-8-one derivatives III–VIII in 28–49% yield (Scheme 1). The reaction was accompanied by concurrent Danilov rearrangement [9], so that 2 equiv of pivalaldehyde was necessary.