【作者】 孙静； 李勤； 崔育新； 肖强； 巨勇；

【Author】 Jing Sun Qin Li Yu-xin Cui* (National Laboratory of Natural and Biomimetic Drugs,Medical and Health Analysis Center,Peking University,Beijing 100083) QiangXiao YongJu (Department of Chemistry,Tsinghua University,Beijing 100084)

【机构】 北京大学天然药物及仿生药物国家重点实验室医药卫生分析中心； 清华大学化学系；

【摘要】 <正>酰胺键广泛存在于生物活性分子中,如多肽和生物碱。由于氮原子上孤对电子离域到羰基上,酰氨键表现出较强的双键性质(Scheme 2),从而导致碳氮键不能自由旋转,这种性质对于维持蛋白质的三级结构具有非常重要的作用。更多还原

【Abstract】 Amide bond is naturally occurring in bioactive molecules,such as peptides and alkaloids.The partial double-bond character of the nitrogen-acyl bond,which is retricted to two rotameric states,has an important effect on the three-dimensional structure of proteins.In our process to study the new condensing reagents,a series of amides of piperidin were synthesized.In order to study the characters of amide bond in detail,the ¹H and ¹³C NMR of Compound 1 and Compound 2 were studied at different temperatures.At room temperature,the ¹H spectrum of Compound 1 shows a separate peak for a and b.As we raise the temperature,the peaks begin to broaden and at 70℃ they coalesce. Similarly,in ¹³C spectrum of Compound 1,the peaks of c,d and a,b coalesce at 70℃ and 90 ℃,respectively.But in compound 2,the chemical shifts of a and b are equivalent even at room temperature, because of the conjugation of double bond.更多还原