A facile reaction of aryl Grignard reagents with 4-alkylacetophenones under ultrasonic irradiation is reported. The reaction can be completed within two minutes with a conversion of 15%～95% and gives 1,1-diarylethene...A facile reaction of aryl Grignard reagents with 4-alkylacetophenones under ultrasonic irradiation is reported. The reaction can be completed within two minutes with a conversion of 15%～95% and gives 1,1-diarylethene and tertiary alcohol in the selectivity over 60%～96%(sometimes with 94.4% 1,1-diarylethene ).展开更多
AIM： To evaluate the hepatoprotective roles of （Z）- 5-（4-methoxybenzylidene）thiazolidine-2,4-dione （SKLB010） against carbon tetrachloride （CCI4）-induced acute and chronic liver injury and its underlying mecha...AIM： To evaluate the hepatoprotective roles of （Z）- 5-（4-methoxybenzylidene）thiazolidine-2,4-dione （SKLB010） against carbon tetrachloride （CCI4）-induced acute and chronic liver injury and its underlying mecha- nisms of action.展开更多
Poly(p-phenylene terephthalamide)(PPTA)pulp was prepared by polycondensation of the p-phenylene diamine(PPDA)with terephthaloyl chloride(TPC)in the completely anhydrous solvent system of N-methyl pyrrolidone(NMP)havin...Poly(p-phenylene terephthalamide)(PPTA)pulp was prepared by polycondensation of the p-phenylene diamine(PPDA)with terephthaloyl chloride(TPC)in the completely anhydrous solvent system of N-methyl pyrrolidone(NMP)having calcium chloride,in the presence of poly(vinyl pyrrolidone)(PVP)having a viscosity average molecular weight lower than 40 000.It was confirmed that the polycondensation could be accelerated,the inherent viscosity of the polymer could be increased,and the polymers could be fibrillated more easily by the addition of the PVP.FTIR and X-ray spectra proved that PVP had not combined into molecular chains of the resultant PPTA pulps.The morphology of the resultant pulps,the effect of viscosity average molecular weight,amount and adding mode of PVP on inherent viscosity,specific surface area,and mean length of the resultant pulps were discussed in detail.And the friction and wear properties of the compound reinforced by the resultant pulps were simply investigated.展开更多
Palladium‐catalyzed asymmetric allylic alkylation(AAA)of vinyl benzoxazinanones has become an important strategy for the synthesis of chiral nitrogen‐containing heterocycle compounds.However,the asymmetric synthesis...Palladium‐catalyzed asymmetric allylic alkylation(AAA)of vinyl benzoxazinanones has become an important strategy for the synthesis of chiral nitrogen‐containing heterocycle compounds.However,the asymmetric synthesis of linear‐selective products has rarely been reported.The simultaneous control of regio‐,E/Z‐and enantioselectivities constitutes a major challenge and inhibits the advancement of this chemistry.Herein,we present a palladium‐catalyzed AAA of vinyl benzoxazinanones withα‐thiocyanato ketones,affording various chiral thiocyanates characterized with high linear‐,E‐and stereoselectivities.The reaction has a broad substrate scope and the chiral thiocyanates can be transformed to useful heterocycles.Experimental and computational studies suggest an inner‐sphere mechanism for AAA process,which results from the acidic and coordination effect of the nucleophilic substrates with palladium catalyst.展开更多
文摘A facile reaction of aryl Grignard reagents with 4-alkylacetophenones under ultrasonic irradiation is reported. The reaction can be completed within two minutes with a conversion of 15%～95% and gives 1,1-diarylethene and tertiary alcohol in the selectivity over 60%～96%(sometimes with 94.4% 1,1-diarylethene ).
基金Supported by National Natural Science Foundation of China and National Key Technologies R and D Program of the 11th five-year plan,No.2009ZX09501-015
文摘AIM： To evaluate the hepatoprotective roles of （Z）- 5-（4-methoxybenzylidene）thiazolidine-2,4-dione （SKLB010） against carbon tetrachloride （CCI4）-induced acute and chronic liver injury and its underlying mecha- nisms of action.
文摘Poly(p-phenylene terephthalamide)(PPTA)pulp was prepared by polycondensation of the p-phenylene diamine(PPDA)with terephthaloyl chloride(TPC)in the completely anhydrous solvent system of N-methyl pyrrolidone(NMP)having calcium chloride,in the presence of poly(vinyl pyrrolidone)(PVP)having a viscosity average molecular weight lower than 40 000.It was confirmed that the polycondensation could be accelerated,the inherent viscosity of the polymer could be increased,and the polymers could be fibrillated more easily by the addition of the PVP.FTIR and X-ray spectra proved that PVP had not combined into molecular chains of the resultant PPTA pulps.The morphology of the resultant pulps,the effect of viscosity average molecular weight,amount and adding mode of PVP on inherent viscosity,specific surface area,and mean length of the resultant pulps were discussed in detail.And the friction and wear properties of the compound reinforced by the resultant pulps were simply investigated.
文摘Palladium‐catalyzed asymmetric allylic alkylation(AAA)of vinyl benzoxazinanones has become an important strategy for the synthesis of chiral nitrogen‐containing heterocycle compounds.However,the asymmetric synthesis of linear‐selective products has rarely been reported.The simultaneous control of regio‐,E/Z‐and enantioselectivities constitutes a major challenge and inhibits the advancement of this chemistry.Herein,we present a palladium‐catalyzed AAA of vinyl benzoxazinanones withα‐thiocyanato ketones,affording various chiral thiocyanates characterized with high linear‐,E‐and stereoselectivities.The reaction has a broad substrate scope and the chiral thiocyanates can be transformed to useful heterocycles.Experimental and computational studies suggest an inner‐sphere mechanism for AAA process,which results from the acidic and coordination effect of the nucleophilic substrates with palladium catalyst.
