Clay minerals, especially authigene kaolinite, are abundant in the dawsonite-bearing sandstone from the Gudian and Qian＇an regions in the southern Songliao Basin. The relationship between dawsonite and kaolinite has ...Clay minerals, especially authigene kaolinite, are abundant in the dawsonite-bearing sandstone from the Gudian and Qian＇an regions in the southern Songliao Basin. The relationship between dawsonite and kaolinite has been investigated based on drilling data from 50 wells in the Jilin Oil Field and petrological cbaracteristics analyses on 23 core samples from the Gudian and Qian＇an regions. The study revealed a negative relationship between the content of dawsonite and kaolinite, suggesting that kaolinite was replaced by the dawsonite. Combined with thermodynamics and geochemical analysis published previously, it is concluded that kaolinite is unstable under CO2-rich environments and can transform into dawsonite.展开更多
Lycopodium alkaloids, a unique family of biologically important natural products isolated and characterized from various species of Lycopodium(sensu lato), have attracted extensive attention from chemists and pharmaci...Lycopodium alkaloids, a unique family of biologically important natural products isolated and characterized from various species of Lycopodium(sensu lato), have attracted extensive attention from chemists and pharmacists in the past three decades. Michael addition-based cyclization has been successfully employed as an elegant and efficient ring-construction protocol of constructing key cyclohexanone intermediates in the total synthesis of Lycopodium alkaloids. This mini-review chooses and summarizes several representative total syntheses of various Lycopodium alkaloids in which intramolecular Michael addition severed as the key methodology.展开更多
基金Supported by project of the National Science Foundation of China(Nos.41172091,40672074)
文摘Clay minerals, especially authigene kaolinite, are abundant in the dawsonite-bearing sandstone from the Gudian and Qian＇an regions in the southern Songliao Basin. The relationship between dawsonite and kaolinite has been investigated based on drilling data from 50 wells in the Jilin Oil Field and petrological cbaracteristics analyses on 23 core samples from the Gudian and Qian＇an regions. The study revealed a negative relationship between the content of dawsonite and kaolinite, suggesting that kaolinite was replaced by the dawsonite. Combined with thermodynamics and geochemical analysis published previously, it is concluded that kaolinite is unstable under CO2-rich environments and can transform into dawsonite.
文摘Lycopodium alkaloids, a unique family of biologically important natural products isolated and characterized from various species of Lycopodium(sensu lato), have attracted extensive attention from chemists and pharmacists in the past three decades. Michael addition-based cyclization has been successfully employed as an elegant and efficient ring-construction protocol of constructing key cyclohexanone intermediates in the total synthesis of Lycopodium alkaloids. This mini-review chooses and summarizes several representative total syntheses of various Lycopodium alkaloids in which intramolecular Michael addition severed as the key methodology.
