3,3`-Dioxo-1,1'(3H,3'H)spirobi[isobenzofuran]-5,6,5',6'-tetracarboxylic acid 1 was resolved successfully and the corresponding optically active polyimides PI were synthesized. The properties of the opt...3,3`-Dioxo-1,1'(3H,3'H)spirobi[isobenzofuran]-5,6,5',6'-tetracarboxylic acid 1 was resolved successfully and the corresponding optically active polyimides PI were synthesized. The properties of the optically active PI and the racemic one were investigated. The results showed that the specific rotation of (-)-PI was about two times to that of the (+)-PI, and the regularity of the optically active PI was higher than that of the racemic one.展开更多
The title compounds were prepared by the enzymatic resolution of the corresponding N-acetylated DL-amino acids methyl esters, which were obtained from t-butyl chloride via an 8-step synthesis.
With sol-gel method,nanometer La-Ti composite oxides were prepared.By means of atomic force microscope,the surface pattern,particle size distribution and specific surface area were studied.The newly prepared nanocryst...With sol-gel method,nanometer La-Ti composite oxides were prepared.By means of atomic force microscope,the surface pattern,particle size distribution and specific surface area were studied.The newly prepared nanocrystals of La-Ti composite oxides were used as the catalysts to catalyze the dehydration of external compensated lactic acid to lactide.The lactide product was measured by polarimeter and micropolariscope.The results demonstrate that the ratio between D-lactide and L-lactide will not be equal to 1-1 if nanocrystals of La-Ti composite oxides are used as the catalysts,which implies,that nanocrystals of La-Ti composite oxides may be potential catalysts with a good selectivity.展开更多
Isatoic anhydride was reacted with several L-amino acids to give the corresponding （2S）-N-（o-aminobenzoyl）-2-alkylaminoacetic acids. The latter compounds were treated with phosphoryl chloride under reflux temperat...Isatoic anhydride was reacted with several L-amino acids to give the corresponding （2S）-N-（o-aminobenzoyl）-2-alkylaminoacetic acids. The latter compounds were treated with phosphoryl chloride under reflux temperature to afford the cyclized products, （3S）-3-alkyl-3,4-dihydro- 1 H- 1,4-benzodiazepin-2,5-diones. 2007 M. Bakavoli. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
An optically active bulky aromatic diacid chiral monomer, （2S）-4-[（4-methyl-2-phthalimidylpentanoylamino）benzoylamino]isophthalic acid （1）, containing a rigid phthalimide and flexible L-leucine pendent group was...An optically active bulky aromatic diacid chiral monomer, （2S）-4-[（4-methyl-2-phthalimidylpentanoylamino）benzoylamino]isophthalic acid （1）, containing a rigid phthalimide and flexible L-leucine pendent group was synthesized in five steps. A fast and clean method for direct polyamidation reaction of monomer 1 with various aromatic diamines under microwave irradiation and conventional heating was performed. The polymerization reactions provided optically active polyamides with high yields and inherent viscosities in the range of 0.36-0.74 dL/g. Their thermal properties were evaluated by thermogravimetric analysis （TGA） and differential scanning calorimetry. TGA thermograms show that the polymers are thermally stable, 10% weight loss temperatures are in excess of 385℃, and char yields at 800℃ are higher than 56%. The data obtained from TGA were used to study the kinetics of thermal decomposition of the resulting polymers. The interpretation of kinetic parameters （E, AH, AS and AG） of thermal decomposition stages was evaluated using Coats and Redfern equation.展开更多
A series of novel s-triazolothiadiazoles 3a-h were prepared by condensation reaction of substituted amino triazoles 1a-b with N-phethaloyl-L-amino acids 2a-d in the presence of the phosphoroxy chloride （POC13） as an...A series of novel s-triazolothiadiazoles 3a-h were prepared by condensation reaction of substituted amino triazoles 1a-b with N-phethaloyl-L-amino acids 2a-d in the presence of the phosphoroxy chloride （POC13） as an anhydrous reagent. The structure of all synthesized compounds was confirmed by IR, 1H NMR, arid 13C NMR spectroscopy.展开更多
Novel aromatic-aliphatic poly（amide-imide）s containing chiral units in the main chain and hydroxyl benzamide units in the side chain have been obtained from the step-growth polymerization of 3,5-diamino-N-（4-hydrox...Novel aromatic-aliphatic poly（amide-imide）s containing chiral units in the main chain and hydroxyl benzamide units in the side chain have been obtained from the step-growth polymerization of 3,5-diamino-N-（4-hydroxyphenyl） benzamide （2） with different chiral diacid chlorides （la-le）. Theoretical calculations were done by means of computational chemistry methods to narrate the stable conformation and orientation of each diacid chloride monomers under reaction conditions. These polymers were characterized by conventional techniques. The resulting polymers show good thermal stability. Other physical properties of polymers including crystallinity, inherent viscosity and morphological characteristics were also studied.展开更多
文摘3,3`-Dioxo-1,1'(3H,3'H)spirobi[isobenzofuran]-5,6,5',6'-tetracarboxylic acid 1 was resolved successfully and the corresponding optically active polyimides PI were synthesized. The properties of the optically active PI and the racemic one were investigated. The results showed that the specific rotation of (-)-PI was about two times to that of the (+)-PI, and the regularity of the optically active PI was higher than that of the racemic one.
基金This work was supported by the Natural Science Foundation of Jiangsu Province.
文摘The title compounds were prepared by the enzymatic resolution of the corresponding N-acetylated DL-amino acids methyl esters, which were obtained from t-butyl chloride via an 8-step synthesis.
基金Project(50174059)supported by the National Natural Science Foundation of ChinaProject(Y406469)supported by Natural Science Foundation of Zhejiang Province
文摘With sol-gel method,nanometer La-Ti composite oxides were prepared.By means of atomic force microscope,the surface pattern,particle size distribution and specific surface area were studied.The newly prepared nanocrystals of La-Ti composite oxides were used as the catalysts to catalyze the dehydration of external compensated lactic acid to lactide.The lactide product was measured by polarimeter and micropolariscope.The results demonstrate that the ratio between D-lactide and L-lactide will not be equal to 1-1 if nanocrystals of La-Ti composite oxides are used as the catalysts,which implies,that nanocrystals of La-Ti composite oxides may be potential catalysts with a good selectivity.
文摘Isatoic anhydride was reacted with several L-amino acids to give the corresponding （2S）-N-（o-aminobenzoyl）-2-alkylaminoacetic acids. The latter compounds were treated with phosphoryl chloride under reflux temperature to afford the cyclized products, （3S）-3-alkyl-3,4-dihydro- 1 H- 1,4-benzodiazepin-2,5-diones. 2007 M. Bakavoli. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金supported by the Research Affairs Division Isfahan University of Technology(IUT),IsfahanNational Elite Foundation(NEF) and Center of Excellency in Sensors and Green Chemistry Research(IUT).
文摘An optically active bulky aromatic diacid chiral monomer, （2S）-4-[（4-methyl-2-phthalimidylpentanoylamino）benzoylamino]isophthalic acid （1）, containing a rigid phthalimide and flexible L-leucine pendent group was synthesized in five steps. A fast and clean method for direct polyamidation reaction of monomer 1 with various aromatic diamines under microwave irradiation and conventional heating was performed. The polymerization reactions provided optically active polyamides with high yields and inherent viscosities in the range of 0.36-0.74 dL/g. Their thermal properties were evaluated by thermogravimetric analysis （TGA） and differential scanning calorimetry. TGA thermograms show that the polymers are thermally stable, 10% weight loss temperatures are in excess of 385℃, and char yields at 800℃ are higher than 56%. The data obtained from TGA were used to study the kinetics of thermal decomposition of the resulting polymers. The interpretation of kinetic parameters （E, AH, AS and AG） of thermal decomposition stages was evaluated using Coats and Redfern equation.
基金Malayer Branch,Islamic Azad University for their financial support
文摘A series of novel s-triazolothiadiazoles 3a-h were prepared by condensation reaction of substituted amino triazoles 1a-b with N-phethaloyl-L-amino acids 2a-d in the presence of the phosphoroxy chloride （POC13） as an anhydrous reagent. The structure of all synthesized compounds was confirmed by IR, 1H NMR, arid 13C NMR spectroscopy.
文摘Novel aromatic-aliphatic poly（amide-imide）s containing chiral units in the main chain and hydroxyl benzamide units in the side chain have been obtained from the step-growth polymerization of 3,5-diamino-N-（4-hydroxyphenyl） benzamide （2） with different chiral diacid chlorides （la-le）. Theoretical calculations were done by means of computational chemistry methods to narrate the stable conformation and orientation of each diacid chloride monomers under reaction conditions. These polymers were characterized by conventional techniques. The resulting polymers show good thermal stability. Other physical properties of polymers including crystallinity, inherent viscosity and morphological characteristics were also studied.
