The adsorption process and hydrogenation mechanisms of 2-methylthiophene on the Pt（111） surface have been elucidated using density functional theory（DFT）. The optimal adsorption sites of reactants, intermediates, ...The adsorption process and hydrogenation mechanisms of 2-methylthiophene on the Pt（111） surface have been elucidated using density functional theory（DFT）. The optimal adsorption sites of reactants, intermediates, and products as well as the activation energy and reaction energy of each elementary reactions were investigated. The results turned out that the 2-methylthiophene tilt to the Pt（111） catalyst with the C_1–C_2 double bond at the top site was the most stable. During the hydrogenation process, the heat of reaction almost located at the negative side, so dropping the temperature is good for the occurrence of hydrogenation process. The hydrogenation steps of mechanism take place along C_2→C_3→C_1→C_4→S→C_1 to generate the product of pentane-2-thiol, in which the first step with the highest energy barrier is the rate-determining step.展开更多
In the chemical synthesis of L-syn-p-methylsulfoxide phenylserine ethyl ester(D-ethyl ester),L-tartaric acid or enzymatic resolution is employed to resolve the racemate,and thus obtain the target compound,and the rema...In the chemical synthesis of L-syn-p-methylsulfoxide phenylserine ethyl ester(D-ethyl ester),L-tartaric acid or enzymatic resolution is employed to resolve the racemate,and thus obtain the target compound,and the remaining isomer can be recycled to obtain the raw material.In this study,high-purity L-syn-p-methylsulfoxide phenylserine(L-syn-MPS)was obtained.The kinetics of the D-threonine aldolase enzymatic hydrolysis reaction reveals that D-syn-p-sulfoxylphenylserine resolves well in[BMIM][BF 4]ionic solvents.The D/L-syn-MPS racemate was resolved using a two-phase ionic solvent[BMIM][NTf 2]to afford L-syn-MPS(ee(enantiomeric excess)>99%)and a white solid in 41.7%yield.Therefore,this system is suitable for the separation of insoluble aldehydes and successfully avoids the condensation of hydroxyl aldehydes to form D-anti-MPS.展开更多
A one-pot, four-component reaction of ethyl acetoacetate, hydrazine hydrate, aldehydes, and malononitrile was discussed using Lewis acid catalyst morpholine triflate （MorT） to afford a series of dihydropyrano[2,3-c]...A one-pot, four-component reaction of ethyl acetoacetate, hydrazine hydrate, aldehydes, and malononitrile was discussed using Lewis acid catalyst morpholine triflate （MorT） to afford a series of dihydropyrano[2,3-c]pyrazoles, which were generally catalyzed by organic alkalis. Moderate to excellent yields, no chromatographic purification, and evasion of environmentally hazardous solvents in the reaction process make this protocol very useful for academia and industry.展开更多
基金supported by the Special Program for Key Basic Research of the Ministry of Science and Technology,China(No.2014CB460608)
文摘The adsorption process and hydrogenation mechanisms of 2-methylthiophene on the Pt（111） surface have been elucidated using density functional theory（DFT）. The optimal adsorption sites of reactants, intermediates, and products as well as the activation energy and reaction energy of each elementary reactions were investigated. The results turned out that the 2-methylthiophene tilt to the Pt（111） catalyst with the C_1–C_2 double bond at the top site was the most stable. During the hydrogenation process, the heat of reaction almost located at the negative side, so dropping the temperature is good for the occurrence of hydrogenation process. The hydrogenation steps of mechanism take place along C_2→C_3→C_1→C_4→S→C_1 to generate the product of pentane-2-thiol, in which the first step with the highest energy barrier is the rate-determining step.
基金the Zhejiang Provincial Key R&D Project (Nos. 2020C03006 & 2019-ZJ-JS-03)National Key R&D Program of China (2021YFC2100800)+1 种基金the National Natural Science Foundation of China (Project 21808205)Research and Application Service Platform Project of API Manufacturing Environmental Protection and Safety Technology in China (2020-0107-3-1)。
文摘In the chemical synthesis of L-syn-p-methylsulfoxide phenylserine ethyl ester(D-ethyl ester),L-tartaric acid or enzymatic resolution is employed to resolve the racemate,and thus obtain the target compound,and the remaining isomer can be recycled to obtain the raw material.In this study,high-purity L-syn-p-methylsulfoxide phenylserine(L-syn-MPS)was obtained.The kinetics of the D-threonine aldolase enzymatic hydrolysis reaction reveals that D-syn-p-sulfoxylphenylserine resolves well in[BMIM][BF 4]ionic solvents.The D/L-syn-MPS racemate was resolved using a two-phase ionic solvent[BMIM][NTf 2]to afford L-syn-MPS(ee(enantiomeric excess)>99%)and a white solid in 41.7%yield.Therefore,this system is suitable for the separation of insoluble aldehydes and successfully avoids the condensation of hydroxyl aldehydes to form D-anti-MPS.
文摘A one-pot, four-component reaction of ethyl acetoacetate, hydrazine hydrate, aldehydes, and malononitrile was discussed using Lewis acid catalyst morpholine triflate （MorT） to afford a series of dihydropyrano[2,3-c]pyrazoles, which were generally catalyzed by organic alkalis. Moderate to excellent yields, no chromatographic purification, and evasion of environmentally hazardous solvents in the reaction process make this protocol very useful for academia and industry.
