The effects of the number of imidazoline ring and the length of alkyl group chain of imidazoline derivatives were investigated using quantum chemical calculation,molecular dynamics simulation and experimental techniqu...The effects of the number of imidazoline ring and the length of alkyl group chain of imidazoline derivatives were investigated using quantum chemical calculation,molecular dynamics simulation and experimental techniques.Three corrosion inhibitors including symmetrical lauric acid imidazoline(SAI),tetracyclic lauric acid imidazoline(LAI),and symmetric stearic acid imidazoline(SPI)were synthesized and their inhibition performance was evaluated using weight loss measurement,electrochemical techniques and surface characterization.The results show that SAI and LAI with the same length of alkyl group chain,LAI with more imidazoline rings could supply a better inhibition performance since the increase of active sites.The increase of active sites attached to the metal surface may also change the distribution of corrosion inhibitor,which could limit inhibition performance improvement.While,SAI and SPI with the same number of imidazoline rings,SPI with longer alkyl group chain shows a better inhibition efficiency due to the better hydrophobic performance of alkyl groups.Among the three inhibitors,SPI shows the best inhibition performance,indicating that the alkyl group chain length affects the inhibition performance more obvious than the number of the imidazoline rings.展开更多
The chiral separations of four pharmaceutical racemates which contain N-alkyl groups were satisfactorily resolved using SBE-β-CD as a chiral mobile phase additive （CMPA） in a RP-HPLC system （the resolution is 2.70...The chiral separations of four pharmaceutical racemates which contain N-alkyl groups were satisfactorily resolved using SBE-β-CD as a chiral mobile phase additive （CMPA） in a RP-HPLC system （the resolution is 2.701 for ondansetron hydrochloride, 1.996 for sulpiride, 1.293 for clenbuterol hydrochloride and 0.816 for omeprazole）. In addition, the effects of different parameters such as CD type and CD concentration were investigated. The separation mechanism arises through the combination of several potential interactions, including electrostatic interactions as well as hydrogen bonding interactions and hydrophobic inclusion interactions, which allow for the SBE-β-CD-drug complexation with strong stereoselectivity and stability. The resolution also relates to the number and location of N atoms in the enantiomers. This method will be applicable to the isolation of various types of biologically imoortant enantiomers containing N-alkyl groups.展开更多
AlCl3-mediated cleavage of ethereal methyl–oxygen bond in aroylated 2,7-dimethoxynaphthalene compounds proceeds chemospecifically and regioselectively. The ethereal bond at the β(2)-position of 1-monoaroylated 2,7-d...AlCl3-mediated cleavage of ethereal methyl–oxygen bond in aroylated 2,7-dimethoxynaphthalene compounds proceeds chemospecifically and regioselectively. The ethereal bond at the β(2)-position of 1-monoaroylated 2,7-dimethoxynaphthalene is cleaved readily and predominantly against the β(7)-position, whereas scission of β-ethereal bonds of 1,8-diaroylated 2,7-dimethoxynaphthalene hardly undergoes like the non-aroylated mother frame compound of 2,7-dimethoxynaphthalene.展开更多
基金This work was supported by Scientific and Technological Innovation Team for the Safety of Petroleum Tubular Goods in Southwest Petroleum University[grant number 2018CXTD01].
文摘The effects of the number of imidazoline ring and the length of alkyl group chain of imidazoline derivatives were investigated using quantum chemical calculation,molecular dynamics simulation and experimental techniques.Three corrosion inhibitors including symmetrical lauric acid imidazoline(SAI),tetracyclic lauric acid imidazoline(LAI),and symmetric stearic acid imidazoline(SPI)were synthesized and their inhibition performance was evaluated using weight loss measurement,electrochemical techniques and surface characterization.The results show that SAI and LAI with the same length of alkyl group chain,LAI with more imidazoline rings could supply a better inhibition performance since the increase of active sites.The increase of active sites attached to the metal surface may also change the distribution of corrosion inhibitor,which could limit inhibition performance improvement.While,SAI and SPI with the same number of imidazoline rings,SPI with longer alkyl group chain shows a better inhibition efficiency due to the better hydrophobic performance of alkyl groups.Among the three inhibitors,SPI shows the best inhibition performance,indicating that the alkyl group chain length affects the inhibition performance more obvious than the number of the imidazoline rings.
基金supported by the National Science and Technology Special Projects(Nos.2012ZX 09301-002-001 and 2012 ZX09301-002-006)the Research and Application of New Efficient Analytical Technologies and Methods in Drug Quality Control and Drug Safety(No.2011IM030200)the State Key Laboratory of Bioactive Substances and Functions of Natural Medicines Open Project(No.GTZK201310)
文摘The chiral separations of four pharmaceutical racemates which contain N-alkyl groups were satisfactorily resolved using SBE-β-CD as a chiral mobile phase additive （CMPA） in a RP-HPLC system （the resolution is 2.701 for ondansetron hydrochloride, 1.996 for sulpiride, 1.293 for clenbuterol hydrochloride and 0.816 for omeprazole）. In addition, the effects of different parameters such as CD type and CD concentration were investigated. The separation mechanism arises through the combination of several potential interactions, including electrostatic interactions as well as hydrogen bonding interactions and hydrophobic inclusion interactions, which allow for the SBE-β-CD-drug complexation with strong stereoselectivity and stability. The resolution also relates to the number and location of N atoms in the enantiomers. This method will be applicable to the isolation of various types of biologically imoortant enantiomers containing N-alkyl groups.
文摘AlCl3-mediated cleavage of ethereal methyl–oxygen bond in aroylated 2,7-dimethoxynaphthalene compounds proceeds chemospecifically and regioselectively. The ethereal bond at the β(2)-position of 1-monoaroylated 2,7-dimethoxynaphthalene is cleaved readily and predominantly against the β(7)-position, whereas scission of β-ethereal bonds of 1,8-diaroylated 2,7-dimethoxynaphthalene hardly undergoes like the non-aroylated mother frame compound of 2,7-dimethoxynaphthalene.
