benzofurans and anisole

A general, sustainable dearomatization reaction for nitrogen-containing heterocycles was developed. Under solvent free conditions and without catalyst, the biorenewable methyl coumalate (MC) reacted as an efficient C

Topics: Anisoles; Benzofurans; Catalysis; Cycloaddition Reaction; Fluorescent Dyes; Heterocyclic Compounds; Hydrocarbons, Aromatic; Immunoglobulin G; Indoles; Molecular Structure; Optical Imaging; Pyrones; Pyrroles; Serum Albumin, Bovine; Solvents

Dichlorocarbene (CCl(2)), generated by laser flash photolysis of dichlorodiazirine, formed pi- and O-ylidic complexes with aromatic ethers such as anisole, 1,3-dimethoxybenzene, 1,3,5-trimethoxybenzene, dibenzofuran, and dibenzo-18-crown-6 and with the aromatic ester phenyl acetate. These complexes were visualized by UV-vis spectroscopy, and they retarded the addition of CCl(2) to tetramethylethylene by factors of 18-152. Computational studies based on density functional theory provided structures and energetics for the transient species and rationalized their absorption spectra. Complexes were not observed between CCl(2) and simple, nonaromatic ethers such as THF, dioxane, or 18-crown-6, nor did these ethers much affect the addition rate of CCl(2) to tetramethylethylene. Computations also suggested that pi-complexes of CCl(2) and, e.g., mesitylene and durene, were energetically reasonable transients. Although these species were not detected spectroscopically, the aromatic compounds did slow the addition of CCl(2) to tetramethylethylene by factors of 15 and 31, respectively.

Topics: Anisoles; Benzofurans; Computer Simulation; Crown Ethers; Ethers; Hydrocarbons, Chlorinated; Models, Chemical; Phloroglucinol; Photolysis; Solutions

A Rh(I)-catalyzed demethylation-cyclization sequence for a direct transformation of o-anisole-substituted ynamides to benzofurans is described here. The Ag salt functions synergistically with Rh(I) for the key demethylation step.

Topics: Alkynes; Amides; Anisoles; Benzofurans; Catalysis; Crystallography, X-Ray; Cyclization; Methylation; Models, Molecular; Molecular Structure; Organometallic Compounds; Rhodium; Stereoisomerism

The authors achieved highly efficient degradation of polychlorinated aromatic compounds, including polychlorinated dibenzo-p-dioxins, dibenzofurans, and dioxin-like compounds such as coplanar polychlorinated biphenyls (co-PCBs), which are known as persistent organic pollutants. Degradation was accomplished in 24 h through a simple stirring operation using safe and high workability metallic calcium, which acts as both a scavenger and a reducing agent, and Rh/C catalyst in an alcohol solution under mild conditions in a sealed tube at 25 degrees C without a temperature increase within 0.15 MPa of increasing internal pressure during the reaction. In this system, reductive dechlorination by metallic calcium and catalytic reduction by Rh/C and generated hydrogen gas, without any external addition of hydrogen, exert a synergistic effect on the degradation of chlorinated compounds. Alcohol was used as a proton source and hydrogen, which was generated by a side reaction, causes an increase in the activity of Rh/C catalyst. Through the degradation of 4-chloroanisole in ethyl alcohol, anisole and cyclohexyl methyl ether were obtained in good conversions. Using ethyl alcohol as a solvent, treatment of dioxins and co-PCBs in a solution was markedly effective for degradation to reduce 2806 pg TEQ/ml of initial concentration to 31.8 pg TEQ/ml; its yield was 98.5%. Moreover, degradation in methyl alcohol took place in a 99.3% yield. That concentration ultimately reached 20.3 pg TEQ/ml under a mild wet process. All congeners of dioxins and co-PCBs were degraded in high conversions. In this degradation, lower aliphatic alcohol, such as methyl alcohol, is effective for making a new calcium surface as compared to alcohol with more methylene chains. In addition, it seemed that a higher pressure of hydrogen was easily generated in methyl alcohol, and then catalytic degradation was effectivley influenced.

Topics: Anisoles; Benzofurans; Calcium; Catalysis; Chlorine; Dibenzofurans, Polychlorinated; Ethanol; Gas Chromatography-Mass Spectrometry; Hydrogen; Japan; Methanol; Methyl Ethers; Oxidation-Reduction; Polychlorinated Biphenyls; Polychlorinated Dibenzodioxins; Protons; Temperature; Water Purification