二氢卟吩e_6衍生物的类羟醛缩合反应及阳离子型光敏剂的合成

Aldol-Like Condensations of Chlorin e_6 Derivatives and Synthesis of Cationic Photosensitizers

以脱镁叶绿酸a甲酯为原料,首先通过E环亲核开环和3-位乙烯基氧化制备了3-醛基取代二氢卟吩e_6衍生物5,然后通过其与4-甲基吡啶或2-甲基喹啉的类羟醛缩合反应及碘甲烷甲基化两步法合成了2种阳离子型二氢卟吩e_6衍生物7和9,并对其紫外可见吸收光谱和单线态氧量子产率进行了比较和讨论.结果发现,与二氢卟吩芳香大环共轭连接的吡啶鎓盐和喹啉鎓盐均可使二氢卟吩e_6衍生物的最大吸收波长强烈红移,其中化合物9的最大吸收波长可达737 nm,所合成的新化合物6~9均具有良好的单线态氧量子产率.这些性质表明,本文合成的一系列化合物有潜力作为光敏剂用于光动力疗法研究.

The starting material methyl pheophorbide a is transformed to 3-CHO chlorin e6 derivative 5 by nucleophilic ring-openning of ring E and oxidation of 3-vinyl group. Two cationic chlorin e6 derivatives 7 and 9 are then prepared by the aldol-like condensation of 5 with 4-picoline or quinaldine and subsequent methylation by Me I. The Uv-Vis spectra and singlet oxygen quantum yields of these new compounds are compared and discussed. It is found that the pyridinium or quinolinium substituent conjugated at 32-position leads to strong red-shift of the Qy absorption of chlorin e6 derivatives,and among them compound 9 shows the Qy absorption at 737 nm. Compounds 7-9 also shows good singlet oxygen quantum yield. Those properties indicate their potential application as photosensitizers in photodynamic therapy.