A concise and efficient method for the synthesis of novel 9,10-imethoxybenzo[6,7]oxepino[3,4-b]quinolin13(6H)-one and its derivatives 7a-p has been developed via the intramolecular Friedel-Crafts acylation reactions o...A concise and efficient method for the synthesis of novel 9,10-imethoxybenzo[6,7]oxepino[3,4-b]quinolin13(6H)-one and its derivatives 7a-p has been developed via the intramolecular Friedel-Crafts acylation reactions of 6,7-dimethoxy-2-(phenoxymethyl)quinoline-3-carboxylic acids 6a-p with polyphosphoric acid (PPA) as catalyst and solvent under mild conditions. The key intermediates 6a-p were prepared through the in situ formation of ethyl 6,7-dimethoxy-2-(phenoxymethyl)quinoline-3-carboxylates 5a-p followed by hydrolysis with aqueous ethanolic sodium hydroxide solution. The novel synthetic method has the advantages of good yields, easy work-up, and environmentally friendly character, which may provide a novel highly efficient process for making quinoline and related azaheterocycle libraries.展开更多
The corrosion inhibition properties of 2,6-diphenylpiperidin-4-one (DPP) (1A) and 2,6-diphenyldihydro-2H-thiopyran-4(3H)-one (DPDT) (1B) for mild steel in 1 M phosphoric acid were studied using weight loss, potentiody...The corrosion inhibition properties of 2,6-diphenylpiperidin-4-one (DPP) (1A) and 2,6-diphenyldihydro-2H-thiopyran-4(3H)-one (DPDT) (1B) for mild steel in 1 M phosphoric acid were studied using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopic techniques. The effect of temperature on the corrosion behavior of mild steel has been examined in the temperature range 303 - 328 K. The inhibition efficiency increases with increasing inhibitor concentration but decreases with increasing temperature. Potentiodynamic polarization studies indicated the mixed nature of inhibitors. The adsorption of the inhibitors on mild steel surface obeyed the Langmuir adsorption isotherms. The density functional theory (DFT) at the B3LYP/6- 31G (d) basis set level was performed on 1A and 1B to investigate the correlation between molecular structure and the corresponding inhibition efficiency (%). The quantum chemical parameters such as EHOMO, ELUMO, the energy gap (E), hardness (η), softness (S), dipole moment (μ), electron affinity (A), ionization potential (I), the absolute electronegativity (χ), the fraction of electron transferred (N), electrophilicity index (ω), the back-donation (EBack-donation) and Mulliken population analysis have been calculated.展开更多
文摘A concise and efficient method for the synthesis of novel 9,10-imethoxybenzo[6,7]oxepino[3,4-b]quinolin13(6H)-one and its derivatives 7a-p has been developed via the intramolecular Friedel-Crafts acylation reactions of 6,7-dimethoxy-2-(phenoxymethyl)quinoline-3-carboxylic acids 6a-p with polyphosphoric acid (PPA) as catalyst and solvent under mild conditions. The key intermediates 6a-p were prepared through the in situ formation of ethyl 6,7-dimethoxy-2-(phenoxymethyl)quinoline-3-carboxylates 5a-p followed by hydrolysis with aqueous ethanolic sodium hydroxide solution. The novel synthetic method has the advantages of good yields, easy work-up, and environmentally friendly character, which may provide a novel highly efficient process for making quinoline and related azaheterocycle libraries.
文摘The corrosion inhibition properties of 2,6-diphenylpiperidin-4-one (DPP) (1A) and 2,6-diphenyldihydro-2H-thiopyran-4(3H)-one (DPDT) (1B) for mild steel in 1 M phosphoric acid were studied using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopic techniques. The effect of temperature on the corrosion behavior of mild steel has been examined in the temperature range 303 - 328 K. The inhibition efficiency increases with increasing inhibitor concentration but decreases with increasing temperature. Potentiodynamic polarization studies indicated the mixed nature of inhibitors. The adsorption of the inhibitors on mild steel surface obeyed the Langmuir adsorption isotherms. The density functional theory (DFT) at the B3LYP/6- 31G (d) basis set level was performed on 1A and 1B to investigate the correlation between molecular structure and the corresponding inhibition efficiency (%). The quantum chemical parameters such as EHOMO, ELUMO, the energy gap (E), hardness (η), softness (S), dipole moment (μ), electron affinity (A), ionization potential (I), the absolute electronegativity (χ), the fraction of electron transferred (N), electrophilicity index (ω), the back-donation (EBack-donation) and Mulliken population analysis have been calculated.
