Microwave-assisted reactions are an environmentally friendly approach for synthesizing organic compounds. In this study, oximation of acetylferrocene and acetophenone was conducted under both microwave irradiation and...Microwave-assisted reactions are an environmentally friendly approach for synthesizing organic compounds. In this study, oximation of acetylferrocene and acetophenone was conducted under both microwave irradiation and conventional heating conditions. Acetylferrocene and acetophenone were subjected to oximation under the two conditions in various solvent mixtures, and the extent of conversion was determined by </span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">H nuclear magnetic resonance spectroscopy. Microwave irradiation was found to accelerate the rate of oximation of both acetylferrocene and acetophenone. Acceleration of the reaction under microwave irradiation was attributed to the efficient absorption of microwaves by the ferrocene nucleus.展开更多
Ligand exchange reaction is one of the typical reactions of ferrocene. In this paper, ligand exchange reactions were carried out between ferrocene and various substituted benzenes using aluminum chloride catalysis. Th...Ligand exchange reaction is one of the typical reactions of ferrocene. In this paper, ligand exchange reactions were carried out between ferrocene and various substituted benzenes using aluminum chloride catalysis. The product yields of the reactions with alkanoyl- and alkoxybenzenes were low because of the coordination of aluminum chloride to the oxygens of the benzene substituents. Comparing the reactions using o- and p-dimethoxybenzene, the former was revealed to be less reactive;this is likely due to the deviation of the π-electrons of its benzene ring being larger.展开更多
The relaxation time of several ferrocene derivatives was measured, and the internal rotation was discussed. For almost all the derivatives, the degree of the internal rotation was constant in spite of the different mo...The relaxation time of several ferrocene derivatives was measured, and the internal rotation was discussed. For almost all the derivatives, the degree of the internal rotation was constant in spite of the different molecular weights. However, for (triphenylmethyl)ferrocene, the rotation of the unsubstituted ring would be slower due to the bulkiness of the substituent. Furthermore, the derivatives that have a hydroxyl- or acetyl group on the substituent were also discussed. Their rotation would be influenced by the location of these substituents.展开更多
The Claisen rearrangement is a [3,3]-sigmatropic rearrangement which is an important method for new C-C bond formation in organic synthesis. This reaction is a typical thermal reaction that requires a high temperature...The Claisen rearrangement is a [3,3]-sigmatropic rearrangement which is an important method for new C-C bond formation in organic synthesis. This reaction is a typical thermal reaction that requires a high temperature and long reaction time. In this paper, the acceleration effects of the iron (III) chloride (FeCl3) catalyst and microwave irradiation during the Claisen rearrangement reaction of allyloxyarene derivatives are reported. The FeCl3 catalyst was able to initiate the reaction at low temperature and induced the subsequent cyclization reaction. The moderation of excellent yields was obtained in a short reaction time. The formation of complex ferric-arenes under microwave irradiation conditions to efficiently absorb the microwaves was expected and confirmed.展开更多
The ligand exchange reaction with heterocycles containing nitrogen, oxygen or sulfur atoms was carried out. For the reaction with heterocycles, the order of the reactivity was S-heterocycles > N-heterocycles > O...The ligand exchange reaction with heterocycles containing nitrogen, oxygen or sulfur atoms was carried out. For the reaction with heterocycles, the order of the reactivity was S-heterocycles > N-heterocycles > O-heterocycles. Furthermore, when the results for the heterocycles were compared to those for the corresponding hydrocarbons, the hydrocarbons had a higher reactivity. These results mean that the reactivity would be mainly governed by the electron density of these arenes.展开更多
The ligand exchange reaction is a typical reaction of ferrocenes. This reaction proceeds via the abstraction of a cyclopentadienyl ring by a Lewis acid followed by coordination of an aromatic compound to the resulting...The ligand exchange reaction is a typical reaction of ferrocenes. This reaction proceeds via the abstraction of a cyclopentadienyl ring by a Lewis acid followed by coordination of an aromatic compound to the resulting species. This reaction with conventional heating requires a long reaction time. Furthermore, the reactions with heterocycles are lower than those with the corresponding hydrocarbons, and do not produce any products in some cases. In this paper, the ligand exchange reaction of ferrocene and a heterocyclic aromatic compound during microwave irradiation and its effect are discussed. As a result, for some heterocycles, the decrease in the reaction time was confirmed. Furthermore, under the microwave irradiation conditions, the tendency in which the difference in their reactivities became low was confirmed.展开更多
Ferrocene is an organometallic compound that readily undergoes oxidation in atmosphere under acidic conditions. However, because of its diamagnetic nature, ferrocene does not lend itself to structural analysis by nucl...Ferrocene is an organometallic compound that readily undergoes oxidation in atmosphere under acidic conditions. However, because of its diamagnetic nature, ferrocene does not lend itself to structural analysis by nuclear magnetic resonance (NMR) spectroscopy. In this work, the oxidation of ferrocene and several of its derivatives were analyzed by liquid chromatography-mass spectrometry (LC-MS). An electrospray ionization (ESI) source was used, with picrate serving as the counter ion. This method is particularly effective for studying oxidation of ferrocenes because their reactivity toward oxygen under ambient conditions is low.展开更多
The reaction between diphenylmethanols and substituted benzenes is useful to yield triarylmethane derivatives which are important skeletons in various functional materials and biologically relevant substances. The Rea...The reaction between diphenylmethanols and substituted benzenes is useful to yield triarylmethane derivatives which are important skeletons in various functional materials and biologically relevant substances. The Reactions were carried out under microwave irradiation as environmentally-friendly method. In cyclohexane, the reaction was accelerated under microwave irradiation as compared to under conventional heating. Also, when more than 0.8 equivalents of iron(III) chloride were used, the acceleration was observed. Notably, when iron(III) chloride and arenes were combined, the temperature of the reaction solution rose to 40°C. It is considered that a chemical species was formed upon coordination of iron(III) chloride to the diphenylmethanols or arenes.展开更多
The effect of microwave irradiation on the intermolecular and intramolecular Friedel-Crafts acylation of aromatic compounds was investigated. Microwave irradiation had no effect on the intermolecular reaction but had ...The effect of microwave irradiation on the intermolecular and intramolecular Friedel-Crafts acylation of aromatic compounds was investigated. Microwave irradiation had no effect on the intermolecular reaction but had an accelerating effect on the intramolecular reaction. This enhanced intramolecular reactivity that was attributed to the high probability of close proximity between the reaction sites.展开更多
Rearrangements of the 1- and 2-cinnamyloxynaphthalenes undergo in diethylene glycol and decalin with solvent de-pendence. In 2-cinnamyloxynaphthalene, the Claisen rearrangement occurs regardless of the solvents. Howev...Rearrangements of the 1- and 2-cinnamyloxynaphthalenes undergo in diethylene glycol and decalin with solvent de-pendence. In 2-cinnamyloxynaphthalene, the Claisen rearrangement occurs regardless of the solvents. However, for the 1-analogue, the Claisen rearrangement occurs in decalin, while both the Claisen and intermolecular rearrangements occur at higher temperatures in diethylene glycol.展开更多
文摘Microwave-assisted reactions are an environmentally friendly approach for synthesizing organic compounds. In this study, oximation of acetylferrocene and acetophenone was conducted under both microwave irradiation and conventional heating conditions. Acetylferrocene and acetophenone were subjected to oximation under the two conditions in various solvent mixtures, and the extent of conversion was determined by </span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">H nuclear magnetic resonance spectroscopy. Microwave irradiation was found to accelerate the rate of oximation of both acetylferrocene and acetophenone. Acceleration of the reaction under microwave irradiation was attributed to the efficient absorption of microwaves by the ferrocene nucleus.
文摘Ligand exchange reaction is one of the typical reactions of ferrocene. In this paper, ligand exchange reactions were carried out between ferrocene and various substituted benzenes using aluminum chloride catalysis. The product yields of the reactions with alkanoyl- and alkoxybenzenes were low because of the coordination of aluminum chloride to the oxygens of the benzene substituents. Comparing the reactions using o- and p-dimethoxybenzene, the former was revealed to be less reactive;this is likely due to the deviation of the π-electrons of its benzene ring being larger.
文摘The relaxation time of several ferrocene derivatives was measured, and the internal rotation was discussed. For almost all the derivatives, the degree of the internal rotation was constant in spite of the different molecular weights. However, for (triphenylmethyl)ferrocene, the rotation of the unsubstituted ring would be slower due to the bulkiness of the substituent. Furthermore, the derivatives that have a hydroxyl- or acetyl group on the substituent were also discussed. Their rotation would be influenced by the location of these substituents.
文摘The Claisen rearrangement is a [3,3]-sigmatropic rearrangement which is an important method for new C-C bond formation in organic synthesis. This reaction is a typical thermal reaction that requires a high temperature and long reaction time. In this paper, the acceleration effects of the iron (III) chloride (FeCl3) catalyst and microwave irradiation during the Claisen rearrangement reaction of allyloxyarene derivatives are reported. The FeCl3 catalyst was able to initiate the reaction at low temperature and induced the subsequent cyclization reaction. The moderation of excellent yields was obtained in a short reaction time. The formation of complex ferric-arenes under microwave irradiation conditions to efficiently absorb the microwaves was expected and confirmed.
文摘The ligand exchange reaction with heterocycles containing nitrogen, oxygen or sulfur atoms was carried out. For the reaction with heterocycles, the order of the reactivity was S-heterocycles > N-heterocycles > O-heterocycles. Furthermore, when the results for the heterocycles were compared to those for the corresponding hydrocarbons, the hydrocarbons had a higher reactivity. These results mean that the reactivity would be mainly governed by the electron density of these arenes.
文摘The ligand exchange reaction is a typical reaction of ferrocenes. This reaction proceeds via the abstraction of a cyclopentadienyl ring by a Lewis acid followed by coordination of an aromatic compound to the resulting species. This reaction with conventional heating requires a long reaction time. Furthermore, the reactions with heterocycles are lower than those with the corresponding hydrocarbons, and do not produce any products in some cases. In this paper, the ligand exchange reaction of ferrocene and a heterocyclic aromatic compound during microwave irradiation and its effect are discussed. As a result, for some heterocycles, the decrease in the reaction time was confirmed. Furthermore, under the microwave irradiation conditions, the tendency in which the difference in their reactivities became low was confirmed.
文摘Ferrocene is an organometallic compound that readily undergoes oxidation in atmosphere under acidic conditions. However, because of its diamagnetic nature, ferrocene does not lend itself to structural analysis by nuclear magnetic resonance (NMR) spectroscopy. In this work, the oxidation of ferrocene and several of its derivatives were analyzed by liquid chromatography-mass spectrometry (LC-MS). An electrospray ionization (ESI) source was used, with picrate serving as the counter ion. This method is particularly effective for studying oxidation of ferrocenes because their reactivity toward oxygen under ambient conditions is low.
文摘The reaction between diphenylmethanols and substituted benzenes is useful to yield triarylmethane derivatives which are important skeletons in various functional materials and biologically relevant substances. The Reactions were carried out under microwave irradiation as environmentally-friendly method. In cyclohexane, the reaction was accelerated under microwave irradiation as compared to under conventional heating. Also, when more than 0.8 equivalents of iron(III) chloride were used, the acceleration was observed. Notably, when iron(III) chloride and arenes were combined, the temperature of the reaction solution rose to 40°C. It is considered that a chemical species was formed upon coordination of iron(III) chloride to the diphenylmethanols or arenes.
文摘The effect of microwave irradiation on the intermolecular and intramolecular Friedel-Crafts acylation of aromatic compounds was investigated. Microwave irradiation had no effect on the intermolecular reaction but had an accelerating effect on the intramolecular reaction. This enhanced intramolecular reactivity that was attributed to the high probability of close proximity between the reaction sites.
文摘Rearrangements of the 1- and 2-cinnamyloxynaphthalenes undergo in diethylene glycol and decalin with solvent de-pendence. In 2-cinnamyloxynaphthalene, the Claisen rearrangement occurs regardless of the solvents. However, for the 1-analogue, the Claisen rearrangement occurs in decalin, while both the Claisen and intermolecular rearrangements occur at higher temperatures in diethylene glycol.
