A new debenzylation of benzyl esters by silica-supported sodium hydrogen sulfate is described. The debenzylation could be achieved selectively and efficiently in good to excellent yields without affecting sensitive fu...A new debenzylation of benzyl esters by silica-supported sodium hydrogen sulfate is described. The debenzylation could be achieved selectively and efficiently in good to excellent yields without affecting sensitive functional groups such as nitro, unsaturated bonds, and ethyl ester.展开更多
A rosmarinic acid derivative, tetramethyl ether of rosmarinic acid benzyl ester, was synthesized. This is the first report of building this structural skeleton.
A salvianolic acid A derivative, hexamethyl ether of salvianolic acid A benzyl ester, was synthesized in fourteen steps. The overall yield was 3.4 parts per thousand. The compound was identified by (1)HNMR and MS. Thi...A salvianolic acid A derivative, hexamethyl ether of salvianolic acid A benzyl ester, was synthesized in fourteen steps. The overall yield was 3.4 parts per thousand. The compound was identified by (1)HNMR and MS. This is the first report of building this structural skeleton.展开更多
Computational strategies have been employed to investigate the influence of the nature of monomers and cross-linker in order to design three dimensional imprinted polymers with selective recognition sites for L-phenyl...Computational strategies have been employed to investigate the influence of the nature of monomers and cross-linker in order to design three dimensional imprinted polymers with selective recognition sites for L-phenylalanine benzyl ester(L-PABE)molecule.Here,computational chemistry methods were applied to screen the molar quantity of functional monomers that interact with one mole of the template molecule.Effects of the nature of functional monomer,cross-linker,and molar ratio were determined computationally using density functional calculations with B3LYP functional and generic 6-31G basis set.Methacrylic acid(MAA)and ethylene glycol dimethacrylate(EGDMA)were used as the functional monomer and crosslinking agent,respectively.L-PABE imprinted polymer layered on multiwalled carbon nanotube(MWCNT)and conventional bulk MIP were synthesised and characterized as well.To investigate the influence of pre-organization of binding sites on the selectivity of L-PABE,respective non-imprinted polymers were also synthesised.MWCNT-MIPs and MIPs exhibited the highest adsorption capacity towards L-PABE.The synthesized polymers revealed characteristic adsorption features and selectivity towards L-PABE in comparison with those of its enantiomer analogues.展开更多
NaBH<sub>4</sub>, CH<sub>3</sub>CO<sub>2</sub>H, Pd/C has been described as an effective reagent system to hydrogenate alkenes. Here, we show that the hydrogenation occurs chemosele...NaBH<sub>4</sub>, CH<sub>3</sub>CO<sub>2</sub>H, Pd/C has been described as an effective reagent system to hydrogenate alkenes. Here, we show that the hydrogenation occurs chemoselectively, making it possible to hydrogenate alkenes under Pd/C catalysis with hydrogen created in situ without O- or N-debenzylation.展开更多
Several aromatic ring-substituted N-acetyl-phenylalanine methyl esters were treated with POCl3 in refluxing benzene, which is the typical condition of B-N reaction. It was found that the normal B-N product 3, 4-dihydr...Several aromatic ring-substituted N-acetyl-phenylalanine methyl esters were treated with POCl3 in refluxing benzene, which is the typical condition of B-N reaction. It was found that the normal B-N product 3, 4-dihydroisoquinoline-3-carboxylic acid methyl ester and/or 5-benzyl-2-methyl-4-methoxy oxazole could be obtained. The result depended mainly upon the electron-donating property of the substitutes on the benzene ring. Strong electron-donating groups located at para- or ortho- to the cyclization site will facilitate the formation of the normal B-N product 2. On the other hand, the absence or weak electron-donating groups tended to yield the oxazole product 3. It was established that the formation of benzyl oxazole is the competitive path with the B-N reaction. In this article, an explanation was given based on the mechanism of Bishler-Napieralski reaction.展开更多
基金support from National Science Foundation of China(Nos.03772648 and 30721005)Knowledge Innovation Program of the Chinese Academy of Sciences(No.06G8031014)
文摘A new debenzylation of benzyl esters by silica-supported sodium hydrogen sulfate is described. The debenzylation could be achieved selectively and efficiently in good to excellent yields without affecting sensitive functional groups such as nitro, unsaturated bonds, and ethyl ester.
文摘A rosmarinic acid derivative, tetramethyl ether of rosmarinic acid benzyl ester, was synthesized. This is the first report of building this structural skeleton.
文摘A salvianolic acid A derivative, hexamethyl ether of salvianolic acid A benzyl ester, was synthesized in fourteen steps. The overall yield was 3.4 parts per thousand. The compound was identified by (1)HNMR and MS. This is the first report of building this structural skeleton.
文摘Computational strategies have been employed to investigate the influence of the nature of monomers and cross-linker in order to design three dimensional imprinted polymers with selective recognition sites for L-phenylalanine benzyl ester(L-PABE)molecule.Here,computational chemistry methods were applied to screen the molar quantity of functional monomers that interact with one mole of the template molecule.Effects of the nature of functional monomer,cross-linker,and molar ratio were determined computationally using density functional calculations with B3LYP functional and generic 6-31G basis set.Methacrylic acid(MAA)and ethylene glycol dimethacrylate(EGDMA)were used as the functional monomer and crosslinking agent,respectively.L-PABE imprinted polymer layered on multiwalled carbon nanotube(MWCNT)and conventional bulk MIP were synthesised and characterized as well.To investigate the influence of pre-organization of binding sites on the selectivity of L-PABE,respective non-imprinted polymers were also synthesised.MWCNT-MIPs and MIPs exhibited the highest adsorption capacity towards L-PABE.The synthesized polymers revealed characteristic adsorption features and selectivity towards L-PABE in comparison with those of its enantiomer analogues.
文摘NaBH<sub>4</sub>, CH<sub>3</sub>CO<sub>2</sub>H, Pd/C has been described as an effective reagent system to hydrogenate alkenes. Here, we show that the hydrogenation occurs chemoselectively, making it possible to hydrogenate alkenes under Pd/C catalysis with hydrogen created in situ without O- or N-debenzylation.
文摘Several aromatic ring-substituted N-acetyl-phenylalanine methyl esters were treated with POCl3 in refluxing benzene, which is the typical condition of B-N reaction. It was found that the normal B-N product 3, 4-dihydroisoquinoline-3-carboxylic acid methyl ester and/or 5-benzyl-2-methyl-4-methoxy oxazole could be obtained. The result depended mainly upon the electron-donating property of the substitutes on the benzene ring. Strong electron-donating groups located at para- or ortho- to the cyclization site will facilitate the formation of the normal B-N product 2. On the other hand, the absence or weak electron-donating groups tended to yield the oxazole product 3. It was established that the formation of benzyl oxazole is the competitive path with the B-N reaction. In this article, an explanation was given based on the mechanism of Bishler-Napieralski reaction.
