Under regular heating and microwave irradiation, 3-alkyl substituted imidazo[1,5-a] pyridines were synthesized from 2,2＇- pyridil, di-2-pyridyl ketone and aliphatic aldehydes in the presence of ammonium acetate and a...Under regular heating and microwave irradiation, 3-alkyl substituted imidazo[1,5-a] pyridines were synthesized from 2,2＇- pyridil, di-2-pyridyl ketone and aliphatic aldehydes in the presence of ammonium acetate and acetic acid. Compared to the traditional heating condition, the reaction time under microwave irradiation was shorter and 3-alkyl imidazo[1,5-a]pyddines were given in higher yield.展开更多
Although there was a strong steric effect,isopentenyl and geranyl moieties were successfully introduced into C3 position in flavone skeleton so as to synthesize the 3-isopentenyl flavone and 3-geranyl flavone under tw...Although there was a strong steric effect,isopentenyl and geranyl moieties were successfully introduced into C3 position in flavone skeleton so as to synthesize the 3-isopentenyl flavone and 3-geranyl flavone under two cyclization conditions（AcOH/HCl and concentrated H 2 SO 4 /MeOH） in this report.It was found that the optimum cyclization conditions for 3-isopentenyl flavone and 3-geranyl flavone were,respectively,AcOH/HCl and H 2 SO 4 /MeOH.Furthermore,the donating electron ability is in the sequence 3-geranyl flavone3-isopentenyl flavone according to the density functional theory（DFT） calculations,suggesting the longer alkyl chain at 3-position would be more favorable for enhancing the donating electron ability.The present synthetic routes might reveal potential applicability in our continued studies on the total syntheses of other natural 3-alkyl flavonoids.展开更多
A highly efficient and selective N-alkylation reaction of 2-amino-4H-chromene-3-carbonitrile derivatives using various alcohols as alkylation agent were developed in the presence of AlCl3 as a catalyst as well as CH3C...A highly efficient and selective N-alkylation reaction of 2-amino-4H-chromene-3-carbonitrile derivatives using various alcohols as alkylation agent were developed in the presence of AlCl3 as a catalyst as well as CH3COOH as an additive,in which the cyano group kept inert and the amino group was alkylated in high yields.All the target products were characterized and determined by infrared(IR),1H NMR,13C NMR,and HRMS.And the X-ray structure of product 3ab was obtained.A bimolecular reaction mechanism catalyzed by AlCl3 was proposed under the assistance of CH3COOH.展开更多
Poly（3-alkyl）pyrroles containing phosphonic acid groups with different alkyl segment lengths were chemical synthesized and the properties were measured by FTIR and UV-Vis spectroscopy. FTIR and UV-Vis results showed...Poly（3-alkyl）pyrroles containing phosphonic acid groups with different alkyl segment lengths were chemical synthesized and the properties were measured by FTIR and UV-Vis spectroscopy. FTIR and UV-Vis results showed that the synthesized polymers were in a low doping level through chemical polymerization. By spin-coating on the surface of substrates, the polymer can be used as a humidity sensor. The change of DC electric current of the polypyrroles varies with the chain length of the alkyl substituents. The capacitance increases with the increase of the humidity and resistance decreases with the increase of humidity. This result is different from that ofpolypyrrole without alkyl substituents due to the influence of the phosphonic acid group. The sensor showed the resistive-type at high relative humidity, and the capacitive- type at the low relative humidity. The sensor exhibited very fast response to the change of environment humidity.展开更多
The Cu(I)-catalyzed [4 + 1] annulation of vinyl indoles and a carbene precursor is a powerful method for constructing cyclopentaindole derivatives. Density functional theory(DFT) calculations were used to elucidate th...The Cu(I)-catalyzed [4 + 1] annulation of vinyl indoles and a carbene precursor is a powerful method for constructing cyclopentaindole derivatives. Density functional theory(DFT) calculations were used to elucidate the mechanism and regioselectivity of this reaction. After Cu-assisted indole C3-alkylation, direct1,5-annulation was favored over the Cu-assisted annulation pathway. Furthermore, the regioselectivity for1,5-annulation was attributed to the generated five-membered-ring product being more stable than the three-membered-ring product from 1,3-annulation, which was the kinetically favored pathway.展开更多
基金the Jiangsu Provincial Natural Science Foundation of China （No. BK2004092） the Scientific Research Foundation for the Returned 0verseas Chinese Scholars from State Education Ministry of China Nanjing University Talent Development Foundation.
文摘Under regular heating and microwave irradiation, 3-alkyl substituted imidazo[1,5-a] pyridines were synthesized from 2,2＇- pyridil, di-2-pyridyl ketone and aliphatic aldehydes in the presence of ammonium acetate and acetic acid. Compared to the traditional heating condition, the reaction time under microwave irradiation was shorter and 3-alkyl imidazo[1,5-a]pyddines were given in higher yield.
基金Supported by the National Natural Science Foundation of China(No.20062001)the Natural Science Foundation of Guangxi Zhuang Autonomous Region,China(Nos.0991009 and 0447036)
文摘Although there was a strong steric effect,isopentenyl and geranyl moieties were successfully introduced into C3 position in flavone skeleton so as to synthesize the 3-isopentenyl flavone and 3-geranyl flavone under two cyclization conditions（AcOH/HCl and concentrated H 2 SO 4 /MeOH） in this report.It was found that the optimum cyclization conditions for 3-isopentenyl flavone and 3-geranyl flavone were,respectively,AcOH/HCl and H 2 SO 4 /MeOH.Furthermore,the donating electron ability is in the sequence 3-geranyl flavone3-isopentenyl flavone according to the density functional theory（DFT） calculations,suggesting the longer alkyl chain at 3-position would be more favorable for enhancing the donating electron ability.The present synthetic routes might reveal potential applicability in our continued studies on the total syntheses of other natural 3-alkyl flavonoids.
基金Supported by the National Natural Science Foundation of China(Nos.21506106,21978410)the Natural Science Foundation of Heilongjiang Province,China(No.LC2017004)+2 种基金the Echelon Reserve Leader Fund for the Leading Talent of Heilongjiang Province,Chinathe Fundamental Research Project for Universities in Heilongjiang Province,China(Nos.135209209,135209220,LTSW201735,YSTSXK201853,YSTSXK201859)the Graduate Innovation Foundation of Qiqihar University,China(NO.YJSCX2018-ZD18).
文摘A highly efficient and selective N-alkylation reaction of 2-amino-4H-chromene-3-carbonitrile derivatives using various alcohols as alkylation agent were developed in the presence of AlCl3 as a catalyst as well as CH3COOH as an additive,in which the cyano group kept inert and the amino group was alkylated in high yields.All the target products were characterized and determined by infrared(IR),1H NMR,13C NMR,and HRMS.And the X-ray structure of product 3ab was obtained.A bimolecular reaction mechanism catalyzed by AlCl3 was proposed under the assistance of CH3COOH.
基金supported by the Fundamental Research Funds for the Central Universities,China(No.GK 200902008)
文摘Poly（3-alkyl）pyrroles containing phosphonic acid groups with different alkyl segment lengths were chemical synthesized and the properties were measured by FTIR and UV-Vis spectroscopy. FTIR and UV-Vis results showed that the synthesized polymers were in a low doping level through chemical polymerization. By spin-coating on the surface of substrates, the polymer can be used as a humidity sensor. The change of DC electric current of the polypyrroles varies with the chain length of the alkyl substituents. The capacitance increases with the increase of the humidity and resistance decreases with the increase of humidity. This result is different from that ofpolypyrrole without alkyl substituents due to the influence of the phosphonic acid group. The sensor showed the resistive-type at high relative humidity, and the capacitive- type at the low relative humidity. The sensor exhibited very fast response to the change of environment humidity.
基金supported by the National Natural Science Foundation of China (Nos. 21822303, 21772020 and 22003006)a project (No. 2018CDXZ0002) supported by the Fundamental Research Funds for the Central Universities (Chongqing University)supported by the Graduate Research and Innovation Foundation of Chongqing,China (No. CYB20045)。
文摘The Cu(I)-catalyzed [4 + 1] annulation of vinyl indoles and a carbene precursor is a powerful method for constructing cyclopentaindole derivatives. Density functional theory(DFT) calculations were used to elucidate the mechanism and regioselectivity of this reaction. After Cu-assisted indole C3-alkylation, direct1,5-annulation was favored over the Cu-assisted annulation pathway. Furthermore, the regioselectivity for1,5-annulation was attributed to the generated five-membered-ring product being more stable than the three-membered-ring product from 1,3-annulation, which was the kinetically favored pathway.
