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以7-羟基香豆素为原料,经过Mannich反应化学选择性地得到了8位的7-羟基香豆素Mannich碱,然后在三乙胺存在的条件下,与磷酰二氯氮芥发生环合反应得到了一种新型的香豆素-7,8-环磷酰胺衍生物. 通过中间产物Mannich碱和目标产物的NMR图谱,都证实了Mannich反应的化学选择性位点是7-羟基香豆素的8位而不是6位;通过DEPT、1H-1H COSY,HSQC和HMBC等2D NMR技术对目标化合物的1H 和13C NMR数据进行了全归属和较详细的解析. 相似文献
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Tian-Shung Wu Li-Shian Shi Sheng-Chu Kuo Ching-Yuh Cherng Shu-Fang Tung Che-Ming Teng 《中国化学会会志》1997,44(2):157-161
Lucidenic acid A ( 1 ) and a new lactone, lucidenolactone ( 2 ) were isolated from the fruiting bodies of Ganoderma lucidum. Their structures were elucidated by spectroscopic method and single-crystal X-ray analysis. Lucidenolactone ( 2 ) showed significant antiplatelet aggregation activity. The NMR spectral data of lucidenic acid A were also reassigned. 相似文献
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Wojciech Migda Anna Stankiewicz Edward Szneler Lucyna Ulman Barbara Rys 《Magnetic resonance in chemistry : MRC》2010,48(9):712-717
Temperature‐dependent 1H and 13C‐NMR spectra of the title compounds are presented. Coalescence effects are discussed and assigned to dynamic process—the interconversion of bicyclic system. The free energies of activation covered the range 39–52 kJ/mol. The dioxepane ring adopts twist‐chair (TC) conformation. GIAO/DFT calculation of isotropic shieldings for the set of low‐energy conformations showed that only one conformer is present at 298 K in solution that matched well with experimental data. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Rotational isomerism in enaminonitriles was studied using dynamic NMR spectroscopy and molecular modeling. It was found that the barrier to rotation about Cvinyl-NH bond was higher for enaminonitriles derived from aliphatic amines than that of enaminonitriles derived from aromatic amines. It was also found that the rotational isomerism about the Car-Cvinyl bond also exists in enaminonitriles. 相似文献
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多肽IS4溶液构象的进一步NMR研究 总被引:1,自引:1,他引:0
利用二维核磁共振技术对多肽IS4中除Ser-1外的所有残基质子进行了指认.积分NOESY谱中的相关峰可得到距离约束.二面角的约束来自偶合常数3JNHα.由慢交换质子可得到氢键的约束.在进行距离几何程序计算时利用这些约束可得到一组构象,用能量最优化程序优化后的结果表明,多肽IS4在CF3CD2OH中的构象为α-螺旋. 相似文献
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用1D(NOE差谱、DEPT谱)和2DNMR技术(HHCOSY、HMQC和HMBC)归属了合成抗变态反应平喘新药氮卓艹斯汀两种异构体的1H和13CNMR谱线 相似文献