Ozone mediated nitration of chlorobenzene with nitrogen dioxide over solid acid catalysts is expected to be a green process. The reaction was carried out at ca . 0 ℃. It was found that the solid acid catalysts of SO ...Ozone mediated nitration of chlorobenzene with nitrogen dioxide over solid acid catalysts is expected to be a green process. The reaction was carried out at ca . 0 ℃. It was found that the solid acid catalysts of SO 2- 4/TiO 2 and SO 2- 4/ZrO 2 and a series of SO 2- 4/TiO 2 ZrO 2 catalysts exhibited a fairly good activity for the nitration reaction, whereas SO 2- 4/TiO 2 ZrO 2(atomic ratio 1∶1) gives yield of 62 4% and SO 2- 4/TiO 2 ZrO 2(molar ratio 3∶1) shows a good para selectivity in CH 2Cl 2 solvent. The ortho para isomer ratios( ortho/para ) of the nitration products were varied in range from 1 11 to 0 36. This phenomenon is interpreted in terms of acid amount and acid strength of solid acid catalysts.展开更多
In the presence of catalytic amount of cesium hydroxide the hydrothiolation of alkynyl selenides occurred at room temperature in DMF under nitrogen atmosphere to give exclusive（Z）-1-organoseleno-2-arylthio-1-alkene ...In the presence of catalytic amount of cesium hydroxide the hydrothiolation of alkynyl selenides occurred at room temperature in DMF under nitrogen atmosphere to give exclusive（Z）-1-organoseleno-2-arylthio-1-alkene in excellent yields.It could provide a new and expedient way for the preparation of（Z）-1-arylseleno-2-arylthio-1-alkene.展开更多
3-Iodoindole N-carboximidamides and N-carboximidoates 4 were prepared regioselectively via a sequential aza-Wittig/iodine induced cyclization, starting from easily accessible 2-alkynylphenyl iminophosphorane, isocyana...3-Iodoindole N-carboximidamides and N-carboximidoates 4 were prepared regioselectively via a sequential aza-Wittig/iodine induced cyclization, starting from easily accessible 2-alkynylphenyl iminophosphorane, isocyanates, various nucleophiles and iodine.展开更多
The regioselective allylic alkylation of 1,2-dihydroquinolines and Morita-Baylis-Hillman（MBH） adducts has been developed. By surveying various reaction parameters, we summarized the effects of temperatures, relative...The regioselective allylic alkylation of 1,2-dihydroquinolines and Morita-Baylis-Hillman（MBH） adducts has been developed. By surveying various reaction parameters, we summarized the effects of temperatures, relative reactant doses, catalysts, solvents and N-protected groups on the regioselectivity of this transformation. This method provides a facile protocol for the preparation of allylic a-substituted dihydroquinolines.展开更多
Entecavir can significantly inhibit the replication of HBV-DNA, reduce the HBV-DNA level in blood se- rum. But suffering from low oral bioavailability, entecavir has low intestinal membrane permeability and poor meta-...Entecavir can significantly inhibit the replication of HBV-DNA, reduce the HBV-DNA level in blood se- rum. But suffering from low oral bioavailability, entecavir has low intestinal membrane permeability and poor meta- bolic stability. In this study, 12 different derivatives of entecavir 4＇-ester were regioselectively synthesized and their apical-to-basolateral permeabilities across Caco-2 cells and HBV-DNA inhibitory efficacies were evaluated. Most of the compounds showed high permeabilities across Caco-2 cells compared with entecavir, compounds 5b and 5e also exhibited comparable anti-HBV activities with that of entecavir, especially.展开更多
文摘Ozone mediated nitration of chlorobenzene with nitrogen dioxide over solid acid catalysts is expected to be a green process. The reaction was carried out at ca . 0 ℃. It was found that the solid acid catalysts of SO 2- 4/TiO 2 and SO 2- 4/ZrO 2 and a series of SO 2- 4/TiO 2 ZrO 2 catalysts exhibited a fairly good activity for the nitration reaction, whereas SO 2- 4/TiO 2 ZrO 2(atomic ratio 1∶1) gives yield of 62 4% and SO 2- 4/TiO 2 ZrO 2(molar ratio 3∶1) shows a good para selectivity in CH 2Cl 2 solvent. The ortho para isomer ratios( ortho/para ) of the nitration products were varied in range from 1 11 to 0 36. This phenomenon is interpreted in terms of acid amount and acid strength of solid acid catalysts.
基金Natural Science Foundation of Hunan(No.2009NK3162)National Natural Science Foundation of China(No.21003040,20372020) for financial support
文摘In the presence of catalytic amount of cesium hydroxide the hydrothiolation of alkynyl selenides occurred at room temperature in DMF under nitrogen atmosphere to give exclusive（Z）-1-organoseleno-2-arylthio-1-alkene in excellent yields.It could provide a new and expedient way for the preparation of（Z）-1-arylseleno-2-arylthio-1-alkene.
文摘3-Iodoindole N-carboximidamides and N-carboximidoates 4 were prepared regioselectively via a sequential aza-Wittig/iodine induced cyclization, starting from easily accessible 2-alkynylphenyl iminophosphorane, isocyanates, various nucleophiles and iodine.
文摘The regioselective allylic alkylation of 1,2-dihydroquinolines and Morita-Baylis-Hillman（MBH） adducts has been developed. By surveying various reaction parameters, we summarized the effects of temperatures, relative reactant doses, catalysts, solvents and N-protected groups on the regioselectivity of this transformation. This method provides a facile protocol for the preparation of allylic a-substituted dihydroquinolines.
基金Supported by the National Natural Science Foundation of China（No.51209024） and the Science and Technology Plan of Si- chuan Province, China（No.2010JY0122）.
文摘Entecavir can significantly inhibit the replication of HBV-DNA, reduce the HBV-DNA level in blood se- rum. But suffering from low oral bioavailability, entecavir has low intestinal membrane permeability and poor meta- bolic stability. In this study, 12 different derivatives of entecavir 4＇-ester were regioselectively synthesized and their apical-to-basolateral permeabilities across Caco-2 cells and HBV-DNA inhibitory efficacies were evaluated. Most of the compounds showed high permeabilities across Caco-2 cells compared with entecavir, compounds 5b and 5e also exhibited comparable anti-HBV activities with that of entecavir, especially.
