The quantitative structure-activity relationship （QSAR） of 14 phenoxybenzoic acid derivatives was studied by ab initio method at the HF/6-31G level using Guassian03 software. The optimized structures together with s...The quantitative structure-activity relationship （QSAR） of 14 phenoxybenzoic acid derivatives was studied by ab initio method at the HF/6-31G level using Guassian03 software. The optimized structures together with some characteristic and electric parameters of the title compounds were obtained; some stereo-parameters were calculated by HyperChem software. Stepwise multiple regression and principal component regression methods are adopted to establish multi-parametric models between biological activity and parameters. The results indicated that the lager Ehomo, M, V and LogP, the smaller Etumo and S, and the higher biological activity. A theoretical direction was provided to synthesize some compounds with high activity.展开更多
Two new acetylated flavonoid diglycosides, scutellarein-5-O-[α-L-rhamnopyranosyl-（1 → 4）-β-D-6-O-acetylglucopyranoside]（1）, apigenin-5-O-[α-L-rhamnopyranosyl-（1→ 2）-β-D-3,6-di-O-acetylglucopyranoside] （2...Two new acetylated flavonoid diglycosides, scutellarein-5-O-[α-L-rhamnopyranosyl-（1 → 4）-β-D-6-O-acetylglucopyranoside]（1）, apigenin-5-O-[α-L-rhamnopyranosyl-（1→ 2）-β-D-3,6-di-O-acetylglucopyranoside] （2）, were isolated from the leaves of Cephalotaxus sinensis. Their structures were determined by chemical and spectroscopic methods including HR-FAB-MS,^1H-^1H COSY, HSQC and HMBC experiments.展开更多
Molecular dipole moments computed at the levels of HF/STO-3G, HF/6-31G(d, p), HF/6-311+G(2d, 2p), MP2/6-31G(d, p) and MP2/6-311+G(2d, 2p) have been investigated. HF/6-311+G(2d, 2p) was found to be the relatively good ...Molecular dipole moments computed at the levels of HF/STO-3G, HF/6-31G(d, p), HF/6-311+G(2d, 2p), MP2/6-31G(d, p) and MP2/6-311+G(2d, 2p) have been investigated. HF/6-311+G(2d, 2p) was found to be the relatively good choice to compute MKS charges for reproducing the experimental values of molecular dipole moments. Root mean square deviation of computed dipole moments for 21 small polar molecules is about 0.1969 D.展开更多
文摘涪陵页岩气田开发的巨大成功(JY6-2HF井累产超过3×10^8 m^3)为五峰组-龙马溪组页岩气勘探开发提供了新的启示,这一成功的关键在于①焦石坝地区位于鄂西-渝东五峰组-龙马溪组深水沉积区,WF2-LM4笔石带页岩厚度较大,具有较好的页岩气富集的物质基础;②JY6-2HF井主要穿行在WF2-LM4笔石带页岩层位中,该套优质页岩与中东-北非的"Lower Hot Shale"具有全球可对比性。涪陵、威远和长宁等页岩气田开发井的主要水平段也都在这段笔石带之中,该笔石带页岩具有有机碳含量高(TOC>3%)、有机质孔最发育(有机质孔隙度>4%)和含气量高(6.87^9.02 m^3/t)等特点。综合分析认为,在类似的地质和工程条件下,页岩气井水平轨迹在WF2-LM4笔石带页岩中穿行比例决定了页岩气单井产量和最终可采储量(EUR)。研究成果将为四川盆地及其周缘五峰组-龙马溪组页岩气和世界其他地区志留系页岩气勘探开发提供参考。
基金This work was supported by the Natural Science Foundation of Fujian Province (X0650070)
文摘The quantitative structure-activity relationship （QSAR） of 14 phenoxybenzoic acid derivatives was studied by ab initio method at the HF/6-31G level using Guassian03 software. The optimized structures together with some characteristic and electric parameters of the title compounds were obtained; some stereo-parameters were calculated by HyperChem software. Stepwise multiple regression and principal component regression methods are adopted to establish multi-parametric models between biological activity and parameters. The results indicated that the lager Ehomo, M, V and LogP, the smaller Etumo and S, and the higher biological activity. A theoretical direction was provided to synthesize some compounds with high activity.
文摘Two new acetylated flavonoid diglycosides, scutellarein-5-O-[α-L-rhamnopyranosyl-（1 → 4）-β-D-6-O-acetylglucopyranoside]（1）, apigenin-5-O-[α-L-rhamnopyranosyl-（1→ 2）-β-D-3,6-di-O-acetylglucopyranoside] （2）, were isolated from the leaves of Cephalotaxus sinensis. Their structures were determined by chemical and spectroscopic methods including HR-FAB-MS,^1H-^1H COSY, HSQC and HMBC experiments.
基金The project was supported by the National Science Foundation (29773021) Provincial Educational Foundation of Jiangsu (98KJB150001).
文摘Molecular dipole moments computed at the levels of HF/STO-3G, HF/6-31G(d, p), HF/6-311+G(2d, 2p), MP2/6-31G(d, p) and MP2/6-311+G(2d, 2p) have been investigated. HF/6-311+G(2d, 2p) was found to be the relatively good choice to compute MKS charges for reproducing the experimental values of molecular dipole moments. Root mean square deviation of computed dipole moments for 21 small polar molecules is about 0.1969 D.
