Ahmad reza Bekhradnia - Academia.edu (original) (raw)
Papers by Ahmad reza Bekhradnia
African Journal of Biotechnology, 2008
Thalassemia major is characterized by anemia, iron overload, further potentiation of reactive oxy... more Thalassemia major is characterized by anemia, iron overload, further potentiation of reactive oxygen species (ROS) and damage to major organs, especially the cardiovascular system. Antioxidant and other supportive therapies protect red blood cells (RBC) against antioxidant damage. Chelation therapy reduces iron-related complications and thereby improves quality of life and overall survival. The poor oral bioavailability, short plasma half-life and severe side effects of available chelators are still not optimal. In this study, iron chelating activity of some medicinal plants was determined to find alternative sources with lower side effects in thalassemic patients. Extracts were prepared by soaking dry material of the selected plant in appropriate solvent. Phenol and flavonoid content of the extract were measured by folin ciocalteu and AlCl3 assays. Phenol content of the extracts varied between 9 -290 mg/g. The largest amount of phenolic compounds and highest chelating activity were...
Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 2012
A convenient and rapid method has been developed for the selective oxidation of several types of ... more A convenient and rapid method has been developed for the selective oxidation of several types of alcohols to related carbonyl compounds under solvent-free conditions. In this study, we report the microwave-assisted selective oxidation of alcohols and a number of organic compounds with pyridinum sulfonate chlorochromate (PSCC) and pyridinum sulfonate fluorochromate (PSFC). The DFT calculations were made at B3LYP/6–31G* levels of
Journal of Cluster Science, 2018
Using density functional theory calculations, the adsorption behavior and electronic sensitivity ... more Using density functional theory calculations, the adsorption behavior and electronic sensitivity of an Al 12 N 12 nanocluster, and an AlN nanocone were investigated toward purinethol (PE) drug. The drug tends to adsorbs on the AlN nanocluster and nanocone via its N atom with adsorption energies about-38.2 and-23.4 kcal/mol, respectively. The AlN nanocluster suffers from a long recovery time of about 3.1 9 10 11 s at 298 K, and cannot be used as a sensor for PE drug. But the electrical conductivity of the AlN nanocone is largely increased by the PE drug adsorption which makes it sensitive to the drug. Also, AlN nanocone benefits from a short recovery time of about 20.8 s at room temperature. Thus, it was concluded that the AlN nanocone may be a promising candidate for detection of PE drug. We also show that by increasing the percentage of Hartree-Fock exchange in the functional, the adsorption energy is increased and the sensitivity is decreased.
RSC Adv., 2017
3-Methyleneindolinone derivatives are important structural motifs found in many compounds of natu... more 3-Methyleneindolinone derivatives are important structural motifs found in many compounds of natural occurrence and pharmacological significance.
RSC Advances, 2016
N-Propargylamines are one of the most useful and versatile building blocks in organic synthesis t... more N-Propargylamines are one of the most useful and versatile building blocks in organic synthesis that are successfully transformed into many significant N-heterocycles.
RSC Advances, 2017
Imidazole and its derivatives are privileged N-heterocyclic structures present in various natural... more Imidazole and its derivatives are privileged N-heterocyclic structures present in various natural products and synthetic pharmaceuticals.
Structural Chemistry, 2016
In this work, the interaction of an aspirin (AS) molecule with the external surface of a boron ni... more In this work, the interaction of an aspirin (AS) molecule with the external surface of a boron nitride fullerene-like nanocage (B 12 N 12) is studied by means of density functional theory (DFT) calculations. Equilibrium geometry, electronic properties, adsorption energy and thermodynamic stability are identified for all of the adsorbed configurations. Four stable configurations are obtained for the interaction of AS molecule with the B 12 N 12 nanocage, with adsorption energies in the range of-10.1 to-37.7 kcal/mol (at the M06-2X/6-31 ? G** level). Our results clearly indicate that Al-doping of the B 12 N 12 tends to increase the adsorption energy and thermodynamic stability of AS molecule over this nanocage. We further study the adsorption of AS over the B 12 N 12 and B 11 N 12 Al in the presence of a protic (water) or aprotic (benzene) solvent. It is found that the calculated binding distances and adsorption energies by the PCM and CPCM solvent models are very similar, especially for the B 12 N 12 complexes. According to time-dependent DFT calculations, the Al-doping can shift estimated k max values toward longer wavelengths (redshift). Solvent effects also have an important influence on the calculated electronic absorption spectra of AS-B 12 N 12 complexes. Keywords B 12 N 12 Á DFT Á Adsorption Á Al-doping Á Optical properties Electronic supplementary material The online version of this article (
RSC Advances, 2016
The pyridine is one of the simplest, yet most important N-heterocycles.
Journal of Mazandaran University of Medical Sciences, Feb 15, 2015
Background and purpose: Quinoxaline derivatives are standing interest of people who work on anti-... more Background and purpose: Quinoxaline derivatives are standing interest of people who work on anti-cancer drugs. There are many reports about using these agents as DNA cleaving, transglutaminase 2 inhibitor, topoisomerase II inhibitor and tumor antibiotic. Other drugs used in treatment of tuberculosis such as isoniazid, pyrazinamide and rifampin have similar structures to quinoxaline and quinoxaline 1, 4di-N-oxide derivatives. This study aimed to prepare 2, 3 diaryl quinoxaline and quinoxaline oxide as potential anticancer and antituberculosis compounds. Materials and methods: The first step involved the conversion of benzaldehyde to benzoine in the presence of sodium cyanide. Direct oxidation of related benzoines to 1,2-diketon compounds were performed using nitric acid which then underwent a nucleophilic attack by phenylenediamine that led to quinoxaline derivatives in high yield. Subsequently, anhydride acetic acid and hydrogen peroxide was employed for the oxidation quinoxaline derivatives to desired 1,4-N-oxide quinoxaline. Results: The 2,3-diarylquinoxaline and quinoxaline oxide derivatives were synthesized and their chemical structures were confirmed using 1 H-NMR and IR spectroscopy. Conclusion: In this study an efficient method was developed for the preparation of novel derivatives of quinoxaline and 1,4-N-oxide quinoxaline as potential anticancer and antituberculosis agents.
RSC Advances, 2016
A walk around the new avenue to the synthesis of quinoline derivatives from N-propargylamines.
Journal of Mazandaran University of Medical Sciences, Dec 15, 2014
Background and purpose: 1,2 diarylethylene or stilbenes are hydrocarbon derivatives with two phen... more Background and purpose: 1,2 diarylethylene or stilbenes are hydrocarbon derivatives with two phenyl group bonded to the double bond carbons. There are two isomers of stilbenes that Z-isomer is less stable than E-isomer. However, the Z-isomer is stronger than E-isomer as potent cyclooxygenase-2 (COX-2) inhibitor. E and Z isomers are interconverted through photochemical irradiation. In this research, Z-isomer was converted to E-isomer by irradiation in photoreactor that could be used as COX-2 inhibitor. Materials and methods: The reaction of p-bromothiophenol with dimethyl lsulfate in an aqueous sodium hydroxide solution produced p-bromothioanisole. Mentioned product was reacted with 4x-styrene via Heck olefination. The olefination was performed with Bu 4 N + Cl-, LiOAc and LiCl in the presence of Pd (II) as a catalyst in DMF. E-1,2 diarylethylene derivatives were irradiated in photo-reactor and their photochemical products were isolated after irradiating by column chromatography. Results: 1,2-diarylstilbene derivatives were produced and their chemical structure were evaluated by 1 H-NMR and IR spectroscopy. UV-vis absorption spectra were measured for all compounds before and after radiation. The photochemical product was isolated and identified Conclusion: E-diarylestilbenes were produced in the presence of Pd (II) and converted to more important Z-isomer by irradiation in photo-reactor
Acta Medica Iranica, Dec 1, 2011
Pakistan journal of pharmaceutical sciences
AFRICAN JOURNAL OF BIOTECHNOLOGY
Recently we described the design and synthesis of four bupropion analogues, 3-Methyl-6-(substitut... more Recently we described the design and synthesis of four bupropion analogues, 3-Methyl-6-(substitutedamino) propionyl]-2-benzoxazolinone as antidepressant. Bupropion is a norepinephrine and dopamine reuptake inhibitor which is used as antidepressant. These compounds were studied for the antidepressant activity using forced swimming test in mice. All analogues were found to be effective in comparison to control at the doses 2.5-20 mg/kg. The activity of analogues was comparable to that of bupropion at the some doses. In addition, antioxidant activity of these derivatives was investigated, employing DPPH radical scavenging activity. IC 50 was in the order:
Dalton Trans., 2015
The computational studies on the mechanism of the iron-catalyzed cross-coupling revealed that the... more The computational studies on the mechanism of the iron-catalyzed cross-coupling revealed that the AT pathway requires less energy than the regular OA pathway.
Spectroscopy Letters, 2005
Isotope Effects by Comparing 1 H-and 2 D-NMR Spectra of 9,90-Bisbicyclo[4.3.0]- cyclonona-2,4,7-t... more Isotope Effects by Comparing 1 H-and 2 D-NMR Spectra of 9,90-Bisbicyclo[4.3.0]- cyclonona-2,4,7-triene ... MZ Kassaee Department of Chemistry, University of Tarbiat Modarres, Pole-Gisha, Tehran, Iran ... AR Bekhradnia Department of Chemistry, ...
Monatshefte für Chemie - Chemical Monthly, 2007
Conformational analysis and frequency calculation were achieved for 1-phenyl-1,2-propandione 1-ox... more Conformational analysis and frequency calculation were achieved for 1-phenyl-1,2-propandione 1-oxime and its four tautomers: 1-nitroso-1-phenyl-1-propen-2-ol, 1nitroso-1-phenyl-2-propanone, 2-hydroxy-1-phenyl-propenone oxime, and 3-nitroso-3-phenyl-propen-2-ol. Calculations were carried out at the Hartree-Fock (HF), Density Functional Theory (B3LYP), and the second-order Møller-Plesset perturbation (MP2) levels of theory using 6-31G Ã and 6-311G ÃÃ basis sets. Five conformers with no imaginary vibrational frequency were obtained by free rotations around three single bonds of 1-phenyl-1,2-propandione-1-oxime: Ph-C(NOH)C(O)CH 3 , PhC(NOH)-C(O)CH 3 , and PhC(N-OH)C(O)CH 3. Similarly, eight structures with no imaginary vibrational frequency were encountered upon rotations around three single bonds of 1-nitroso-1-phenyl-1-propen-2-ol: Ph-C(NO)C(OH)CH 3 , PhC(N-O)C(OH)CH 3 , and PhC(NO)C(-OH)CH 3. In the same manner, six minima were found through rotations around three single bonds of 1-nitroso-1-phenyl-2-propanone: Ph-CH(NO)C(O)CH 3 , PhCH(-NO)C(O)CH 3 , and PhCH(NO)-C(O)CH 3. Also, two minima were found through rotations around four single bonds of 2-hydroxy-1-phenyl-propenone oxime: Ph-C(NOH)C(OH)CH 2 , PhC(N-OH)C(OH)CH 2 , PhC(NOH)-C(OH)CH 2 , and Ph-C(NOH)C(-OH)CH 2. Finally, two minima were found through rotations around four single bonds of 3-nitroso-3-phenyl-propen-2-ol: Ph-CH(NO)C(OH)CH 2 , PhCH(-NO)C(OH)CH 2 , PhCH(NO)-C(OH)CH 2 , and PhCH(NO)C(-OH)CH 2. Interconversions within the above sets of conformers were probed through scanning (one and=or two dimensional), and=or QST3 techniques. The order of the stability of global minima encountered was: 1,2-propandione-1-oxime> 1-nitroso-1-phenyl-2-propanone> 1-nitroso-1-phenyl-1-propen-2-ol > 2-hydroxy-1-phenyl-propenone oxime> 3-nitroso-3-phenyl-propen-2-ol. Hydrogen bonding appears significant in tautomers of 1-nitroso-1-phenyl-1-propen-2-ol and 2-hydroxy-1-phenyl-propenone oxime. The CIS simulated l max for the first excited singlet state (S 1) of 1-phenyl-1,2-propandione 1-oxime is 300.4 nm, which was comparable to its experimental l max of 312.0 nm. The calculated IR spectra of 1-phenyl-1,2-propandione 1-oxime and its tautomers were compared to the experimental spectra.
The Journal of Organic Chemistry, 1986
The oxidation of several representative organoboranes with anhydrous trimethylamine N-oxide (TMAN... more The oxidation of several representative organoboranes with anhydrous trimethylamine N-oxide (TMANO) is described. Acyclic trialkylboranes are oxidized sequentially with stoichiometric quantities of the reagent to give first borinate, then boronate, and finally borate esters. Unsymmetrical trialkylboranes are oxidized with 1 equiv of TMANO to give mixtures of borinate esters with the oxidative reactivity of the alkyl groups following the order: 3' > 2" > 1". By contrast, the monooxidation of B-substituted derivatives of 9-borabicyclo[3.3.1]nonane give the 9-oxa-l0-borabicyclo[3.3.2]decane product, exclusively. The alcoholysis of 9-BBN followed by oxidation with TMANO gives the corresponding R-alkoxyoxaborabicyclic boronates in good yield. Unlike the acyclic boron esters, the further oxidation of these bicyclic compounds with TMANO is slow and gives product mixtures. Moreover, no volatile products containing the 1,3,2-dioxaborocane ring system could be isolated from these mixtures. The reaction of B-tert-butylborinanes with 1 equiv of TMANO also results in the oxidation of the ring B-C bond exclusively. The mechanism of the oxidation process is discussed in terms of an antiperiplanar conformation of the leaving trimethylamine to the specific B-C bond which is undergoing oxidation. This model is consistent with the observed experimental results. Spectroscopic data for the new organoboranes are presented.
African Journal of Biotechnology, 2008
Thalassemia major is characterized by anemia, iron overload, further potentiation of reactive oxy... more Thalassemia major is characterized by anemia, iron overload, further potentiation of reactive oxygen species (ROS) and damage to major organs, especially the cardiovascular system. Antioxidant and other supportive therapies protect red blood cells (RBC) against antioxidant damage. Chelation therapy reduces iron-related complications and thereby improves quality of life and overall survival. The poor oral bioavailability, short plasma half-life and severe side effects of available chelators are still not optimal. In this study, iron chelating activity of some medicinal plants was determined to find alternative sources with lower side effects in thalassemic patients. Extracts were prepared by soaking dry material of the selected plant in appropriate solvent. Phenol and flavonoid content of the extract were measured by folin ciocalteu and AlCl3 assays. Phenol content of the extracts varied between 9 -290 mg/g. The largest amount of phenolic compounds and highest chelating activity were...
Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 2012
A convenient and rapid method has been developed for the selective oxidation of several types of ... more A convenient and rapid method has been developed for the selective oxidation of several types of alcohols to related carbonyl compounds under solvent-free conditions. In this study, we report the microwave-assisted selective oxidation of alcohols and a number of organic compounds with pyridinum sulfonate chlorochromate (PSCC) and pyridinum sulfonate fluorochromate (PSFC). The DFT calculations were made at B3LYP/6–31G* levels of
Journal of Cluster Science, 2018
Using density functional theory calculations, the adsorption behavior and electronic sensitivity ... more Using density functional theory calculations, the adsorption behavior and electronic sensitivity of an Al 12 N 12 nanocluster, and an AlN nanocone were investigated toward purinethol (PE) drug. The drug tends to adsorbs on the AlN nanocluster and nanocone via its N atom with adsorption energies about-38.2 and-23.4 kcal/mol, respectively. The AlN nanocluster suffers from a long recovery time of about 3.1 9 10 11 s at 298 K, and cannot be used as a sensor for PE drug. But the electrical conductivity of the AlN nanocone is largely increased by the PE drug adsorption which makes it sensitive to the drug. Also, AlN nanocone benefits from a short recovery time of about 20.8 s at room temperature. Thus, it was concluded that the AlN nanocone may be a promising candidate for detection of PE drug. We also show that by increasing the percentage of Hartree-Fock exchange in the functional, the adsorption energy is increased and the sensitivity is decreased.
RSC Adv., 2017
3-Methyleneindolinone derivatives are important structural motifs found in many compounds of natu... more 3-Methyleneindolinone derivatives are important structural motifs found in many compounds of natural occurrence and pharmacological significance.
RSC Advances, 2016
N-Propargylamines are one of the most useful and versatile building blocks in organic synthesis t... more N-Propargylamines are one of the most useful and versatile building blocks in organic synthesis that are successfully transformed into many significant N-heterocycles.
RSC Advances, 2017
Imidazole and its derivatives are privileged N-heterocyclic structures present in various natural... more Imidazole and its derivatives are privileged N-heterocyclic structures present in various natural products and synthetic pharmaceuticals.
Structural Chemistry, 2016
In this work, the interaction of an aspirin (AS) molecule with the external surface of a boron ni... more In this work, the interaction of an aspirin (AS) molecule with the external surface of a boron nitride fullerene-like nanocage (B 12 N 12) is studied by means of density functional theory (DFT) calculations. Equilibrium geometry, electronic properties, adsorption energy and thermodynamic stability are identified for all of the adsorbed configurations. Four stable configurations are obtained for the interaction of AS molecule with the B 12 N 12 nanocage, with adsorption energies in the range of-10.1 to-37.7 kcal/mol (at the M06-2X/6-31 ? G** level). Our results clearly indicate that Al-doping of the B 12 N 12 tends to increase the adsorption energy and thermodynamic stability of AS molecule over this nanocage. We further study the adsorption of AS over the B 12 N 12 and B 11 N 12 Al in the presence of a protic (water) or aprotic (benzene) solvent. It is found that the calculated binding distances and adsorption energies by the PCM and CPCM solvent models are very similar, especially for the B 12 N 12 complexes. According to time-dependent DFT calculations, the Al-doping can shift estimated k max values toward longer wavelengths (redshift). Solvent effects also have an important influence on the calculated electronic absorption spectra of AS-B 12 N 12 complexes. Keywords B 12 N 12 Á DFT Á Adsorption Á Al-doping Á Optical properties Electronic supplementary material The online version of this article (
RSC Advances, 2016
The pyridine is one of the simplest, yet most important N-heterocycles.
Journal of Mazandaran University of Medical Sciences, Feb 15, 2015
Background and purpose: Quinoxaline derivatives are standing interest of people who work on anti-... more Background and purpose: Quinoxaline derivatives are standing interest of people who work on anti-cancer drugs. There are many reports about using these agents as DNA cleaving, transglutaminase 2 inhibitor, topoisomerase II inhibitor and tumor antibiotic. Other drugs used in treatment of tuberculosis such as isoniazid, pyrazinamide and rifampin have similar structures to quinoxaline and quinoxaline 1, 4di-N-oxide derivatives. This study aimed to prepare 2, 3 diaryl quinoxaline and quinoxaline oxide as potential anticancer and antituberculosis compounds. Materials and methods: The first step involved the conversion of benzaldehyde to benzoine in the presence of sodium cyanide. Direct oxidation of related benzoines to 1,2-diketon compounds were performed using nitric acid which then underwent a nucleophilic attack by phenylenediamine that led to quinoxaline derivatives in high yield. Subsequently, anhydride acetic acid and hydrogen peroxide was employed for the oxidation quinoxaline derivatives to desired 1,4-N-oxide quinoxaline. Results: The 2,3-diarylquinoxaline and quinoxaline oxide derivatives were synthesized and their chemical structures were confirmed using 1 H-NMR and IR spectroscopy. Conclusion: In this study an efficient method was developed for the preparation of novel derivatives of quinoxaline and 1,4-N-oxide quinoxaline as potential anticancer and antituberculosis agents.
RSC Advances, 2016
A walk around the new avenue to the synthesis of quinoline derivatives from N-propargylamines.
Journal of Mazandaran University of Medical Sciences, Dec 15, 2014
Background and purpose: 1,2 diarylethylene or stilbenes are hydrocarbon derivatives with two phen... more Background and purpose: 1,2 diarylethylene or stilbenes are hydrocarbon derivatives with two phenyl group bonded to the double bond carbons. There are two isomers of stilbenes that Z-isomer is less stable than E-isomer. However, the Z-isomer is stronger than E-isomer as potent cyclooxygenase-2 (COX-2) inhibitor. E and Z isomers are interconverted through photochemical irradiation. In this research, Z-isomer was converted to E-isomer by irradiation in photoreactor that could be used as COX-2 inhibitor. Materials and methods: The reaction of p-bromothiophenol with dimethyl lsulfate in an aqueous sodium hydroxide solution produced p-bromothioanisole. Mentioned product was reacted with 4x-styrene via Heck olefination. The olefination was performed with Bu 4 N + Cl-, LiOAc and LiCl in the presence of Pd (II) as a catalyst in DMF. E-1,2 diarylethylene derivatives were irradiated in photo-reactor and their photochemical products were isolated after irradiating by column chromatography. Results: 1,2-diarylstilbene derivatives were produced and their chemical structure were evaluated by 1 H-NMR and IR spectroscopy. UV-vis absorption spectra were measured for all compounds before and after radiation. The photochemical product was isolated and identified Conclusion: E-diarylestilbenes were produced in the presence of Pd (II) and converted to more important Z-isomer by irradiation in photo-reactor
Acta Medica Iranica, Dec 1, 2011
Pakistan journal of pharmaceutical sciences
AFRICAN JOURNAL OF BIOTECHNOLOGY
Recently we described the design and synthesis of four bupropion analogues, 3-Methyl-6-(substitut... more Recently we described the design and synthesis of four bupropion analogues, 3-Methyl-6-(substitutedamino) propionyl]-2-benzoxazolinone as antidepressant. Bupropion is a norepinephrine and dopamine reuptake inhibitor which is used as antidepressant. These compounds were studied for the antidepressant activity using forced swimming test in mice. All analogues were found to be effective in comparison to control at the doses 2.5-20 mg/kg. The activity of analogues was comparable to that of bupropion at the some doses. In addition, antioxidant activity of these derivatives was investigated, employing DPPH radical scavenging activity. IC 50 was in the order:
Dalton Trans., 2015
The computational studies on the mechanism of the iron-catalyzed cross-coupling revealed that the... more The computational studies on the mechanism of the iron-catalyzed cross-coupling revealed that the AT pathway requires less energy than the regular OA pathway.
Spectroscopy Letters, 2005
Isotope Effects by Comparing 1 H-and 2 D-NMR Spectra of 9,90-Bisbicyclo[4.3.0]- cyclonona-2,4,7-t... more Isotope Effects by Comparing 1 H-and 2 D-NMR Spectra of 9,90-Bisbicyclo[4.3.0]- cyclonona-2,4,7-triene ... MZ Kassaee Department of Chemistry, University of Tarbiat Modarres, Pole-Gisha, Tehran, Iran ... AR Bekhradnia Department of Chemistry, ...
Monatshefte für Chemie - Chemical Monthly, 2007
Conformational analysis and frequency calculation were achieved for 1-phenyl-1,2-propandione 1-ox... more Conformational analysis and frequency calculation were achieved for 1-phenyl-1,2-propandione 1-oxime and its four tautomers: 1-nitroso-1-phenyl-1-propen-2-ol, 1nitroso-1-phenyl-2-propanone, 2-hydroxy-1-phenyl-propenone oxime, and 3-nitroso-3-phenyl-propen-2-ol. Calculations were carried out at the Hartree-Fock (HF), Density Functional Theory (B3LYP), and the second-order Møller-Plesset perturbation (MP2) levels of theory using 6-31G Ã and 6-311G ÃÃ basis sets. Five conformers with no imaginary vibrational frequency were obtained by free rotations around three single bonds of 1-phenyl-1,2-propandione-1-oxime: Ph-C(NOH)C(O)CH 3 , PhC(NOH)-C(O)CH 3 , and PhC(N-OH)C(O)CH 3. Similarly, eight structures with no imaginary vibrational frequency were encountered upon rotations around three single bonds of 1-nitroso-1-phenyl-1-propen-2-ol: Ph-C(NO)C(OH)CH 3 , PhC(N-O)C(OH)CH 3 , and PhC(NO)C(-OH)CH 3. In the same manner, six minima were found through rotations around three single bonds of 1-nitroso-1-phenyl-2-propanone: Ph-CH(NO)C(O)CH 3 , PhCH(-NO)C(O)CH 3 , and PhCH(NO)-C(O)CH 3. Also, two minima were found through rotations around four single bonds of 2-hydroxy-1-phenyl-propenone oxime: Ph-C(NOH)C(OH)CH 2 , PhC(N-OH)C(OH)CH 2 , PhC(NOH)-C(OH)CH 2 , and Ph-C(NOH)C(-OH)CH 2. Finally, two minima were found through rotations around four single bonds of 3-nitroso-3-phenyl-propen-2-ol: Ph-CH(NO)C(OH)CH 2 , PhCH(-NO)C(OH)CH 2 , PhCH(NO)-C(OH)CH 2 , and PhCH(NO)C(-OH)CH 2. Interconversions within the above sets of conformers were probed through scanning (one and=or two dimensional), and=or QST3 techniques. The order of the stability of global minima encountered was: 1,2-propandione-1-oxime> 1-nitroso-1-phenyl-2-propanone> 1-nitroso-1-phenyl-1-propen-2-ol > 2-hydroxy-1-phenyl-propenone oxime> 3-nitroso-3-phenyl-propen-2-ol. Hydrogen bonding appears significant in tautomers of 1-nitroso-1-phenyl-1-propen-2-ol and 2-hydroxy-1-phenyl-propenone oxime. The CIS simulated l max for the first excited singlet state (S 1) of 1-phenyl-1,2-propandione 1-oxime is 300.4 nm, which was comparable to its experimental l max of 312.0 nm. The calculated IR spectra of 1-phenyl-1,2-propandione 1-oxime and its tautomers were compared to the experimental spectra.
The Journal of Organic Chemistry, 1986
The oxidation of several representative organoboranes with anhydrous trimethylamine N-oxide (TMAN... more The oxidation of several representative organoboranes with anhydrous trimethylamine N-oxide (TMANO) is described. Acyclic trialkylboranes are oxidized sequentially with stoichiometric quantities of the reagent to give first borinate, then boronate, and finally borate esters. Unsymmetrical trialkylboranes are oxidized with 1 equiv of TMANO to give mixtures of borinate esters with the oxidative reactivity of the alkyl groups following the order: 3' > 2" > 1". By contrast, the monooxidation of B-substituted derivatives of 9-borabicyclo[3.3.1]nonane give the 9-oxa-l0-borabicyclo[3.3.2]decane product, exclusively. The alcoholysis of 9-BBN followed by oxidation with TMANO gives the corresponding R-alkoxyoxaborabicyclic boronates in good yield. Unlike the acyclic boron esters, the further oxidation of these bicyclic compounds with TMANO is slow and gives product mixtures. Moreover, no volatile products containing the 1,3,2-dioxaborocane ring system could be isolated from these mixtures. The reaction of B-tert-butylborinanes with 1 equiv of TMANO also results in the oxidation of the ring B-C bond exclusively. The mechanism of the oxidation process is discussed in terms of an antiperiplanar conformation of the leaving trimethylamine to the specific B-C bond which is undergoing oxidation. This model is consistent with the observed experimental results. Spectroscopic data for the new organoboranes are presented.