2种甘氨酸棉酚Schiff碱的光谱分析及PM6半经典计算研究

Spectroscopic analysis and PM6 study of the Schiff bases of gossypol with phenylglycine methyl ester and glycine ethyl ester

目的解析2种甘氨酸棉酚Schiff碱的结构及优势构象。方法制备2种甘氨酸棉酚Schiff碱,并采用红外光谱、二维核磁波谱技术和PM6半经典计算方法进行结构解析。结果光谱分析表明2种甘氨酸棉酚Schiff碱具有烯胺-烯胺结构特征,并归属了所有的碳原子和氢原子的化学位移;PM6研究表明2种甘氨酸棉酚衍生物以烯胺-烯胺构型存在,在能量上更有利,并确定了优势构象。结论 2种甘氨酸棉酚Schiff碱均以烯胺-烯胺形式存在,分子内氢键使烯胺-烯胺结构更稳定。

Objective To investigate the tautomeric forms of Schiff bases of gossypol with phenylglyeine methyl ester and glycine ethyl ester. Methods The Sehiff bases of gossypol with phenylglycine methyl ester and glycine ethyl ester were synthesized and identified by FT-IR ,2D-NMR spectroscopy and the PM6 semi- classical calculation. Results The 1H-NMR and 13 C-NMR signals of the new Sehiff bases were assigned. PM6 semi-classical calculation indicated that enamine-enamine tautomeric forms of the Schiff bases of gossypol with phenylglycine methyl ester and glycine ethyl ester were more stable. Conclusion The Schiff bases of gossypol with phenylglycine methyl ester and glycine ethyl ester exist in enamine-enamine tautomeric form in solution,which is stabilized by the intramolecular hydrogen bonds.