The normally underused ^1H-^15N HMBC spectra of thirteen C18-diterpenoid alkaloids have been determined for the first time. As a result, the significant effects of the substituents of nitrogen atoms, the conformations...The normally underused ^1H-^15N HMBC spectra of thirteen C18-diterpenoid alkaloids have been determined for the first time. As a result, the significant effects of the substituents of nitrogen atoms, the conformations of A ring, and protonation, on the nitrogen-15 chemical shifts are demonstrated.展开更多
A novel biscalixarene with two kinds of calix[4]arene derivative units connected by four bridging chains, was facilely＇ synthesized by ＂1 ＋ 1＂ condensation mode in high yield. The element analyses, ESI-MS, ^1H NMR...A novel biscalixarene with two kinds of calix[4]arene derivative units connected by four bridging chains, was facilely＇ synthesized by ＂1 ＋ 1＂ condensation mode in high yield. The element analyses, ESI-MS, ^1H NMR and ^1H-^1H COSY spectrum showed that the calix[4]arene units of compound 4 were in cone conformations and compound 4 possessed biscalixarene-tube structure. 2007 Fa Fu Yang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
基金the National Natural Science Foundation of China (No.81273387) for the financial support of this research
文摘The normally underused ^1H-^15N HMBC spectra of thirteen C18-diterpenoid alkaloids have been determined for the first time. As a result, the significant effects of the substituents of nitrogen atoms, the conformations of A ring, and protonation, on the nitrogen-15 chemical shifts are demonstrated.
基金Financial support from the National Natural Science Foundation of China （No. 20402002）；Fujian Natural Science Foundation of China （No. 2006J0155）；Program for New Century Excellent Talents in University of Fujian Province were greatly acknowledged.
文摘A novel biscalixarene with two kinds of calix[4]arene derivative units connected by four bridging chains, was facilely＇ synthesized by ＂1 ＋ 1＂ condensation mode in high yield. The element analyses, ESI-MS, ^1H NMR and ^1H-^1H COSY spectrum showed that the calix[4]arene units of compound 4 were in cone conformations and compound 4 possessed biscalixarene-tube structure. 2007 Fa Fu Yang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
