Although there was a strong steric effect,isopentenyl and geranyl moieties were successfully introduced into C3 position in flavone skeleton so as to synthesize the 3-isopentenyl flavone and 3-geranyl flavone under tw...Although there was a strong steric effect,isopentenyl and geranyl moieties were successfully introduced into C3 position in flavone skeleton so as to synthesize the 3-isopentenyl flavone and 3-geranyl flavone under two cyclization conditions(AcOH/HCl and concentrated H 2 SO 4 /MeOH) in this report.It was found that the optimum cyclization conditions for 3-isopentenyl flavone and 3-geranyl flavone were,respectively,AcOH/HCl and H 2 SO 4 /MeOH.Furthermore,the donating electron ability is in the sequence 3-geranyl flavone>3-isopentenyl flavone according to the density functional theory(DFT) calculations,suggesting the longer alkyl chain at 3-position would be more favorable for enhancing the donating electron ability.The present synthetic routes might reveal potential applicability in our continued studies on the total syntheses of other natural 3-alkyl flavonoids.展开更多
随着新冠病毒在全球的快速蔓延,口罩已成为人们生活的必需品。2021年6月,日本制定了针对医用和一般用途口罩的JIS T 9001《医用及通用口罩的性能要求及检测方法》和针对从事疫情防控的医务人员用口罩的JIS T 9002《应对感染的医用口罩...随着新冠病毒在全球的快速蔓延,口罩已成为人们生活的必需品。2021年6月,日本制定了针对医用和一般用途口罩的JIS T 9001《医用及通用口罩的性能要求及检测方法》和针对从事疫情防控的医务人员用口罩的JIS T 9002《应对感染的医用口罩的性能要求及检测方法》。本文介绍了两项新标准的制定背景和关键技术指标,简要分析了日本口罩标准与我国标准的关键差异,为我国口罩产品出口日本提供参考。展开更多
基金supported by the Major Scientific and Technological Project of PetroChina (ZD2019-183-003)Project of National Natural Science Foundation of China (42074133)+1 种基金the Fundamental Research Funds for the Central Universities (19CX02056A)Project of State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development (33550000-21-FW0399-0009)
基金Supported by the National Natural Science Foundation of China(No.20062001)the Natural Science Foundation of Guangxi Zhuang Autonomous Region,China(Nos.0991009 and 0447036)
文摘Although there was a strong steric effect,isopentenyl and geranyl moieties were successfully introduced into C3 position in flavone skeleton so as to synthesize the 3-isopentenyl flavone and 3-geranyl flavone under two cyclization conditions(AcOH/HCl and concentrated H 2 SO 4 /MeOH) in this report.It was found that the optimum cyclization conditions for 3-isopentenyl flavone and 3-geranyl flavone were,respectively,AcOH/HCl and H 2 SO 4 /MeOH.Furthermore,the donating electron ability is in the sequence 3-geranyl flavone>3-isopentenyl flavone according to the density functional theory(DFT) calculations,suggesting the longer alkyl chain at 3-position would be more favorable for enhancing the donating electron ability.The present synthetic routes might reveal potential applicability in our continued studies on the total syntheses of other natural 3-alkyl flavonoids.
文摘随着新冠病毒在全球的快速蔓延,口罩已成为人们生活的必需品。2021年6月,日本制定了针对医用和一般用途口罩的JIS T 9001《医用及通用口罩的性能要求及检测方法》和针对从事疫情防控的医务人员用口罩的JIS T 9002《应对感染的医用口罩的性能要求及检测方法》。本文介绍了两项新标准的制定背景和关键技术指标,简要分析了日本口罩标准与我国标准的关键差异,为我国口罩产品出口日本提供参考。
