摘要
以脱镁叶绿酸甲酯为原料,通过对其3-位乙烯基的氧化,得到3-(2,2-二甲氧基乙基)-3-去乙烯基脱镁叶绿酸甲酯,经过甲酸处理得到3-(2-氧代乙基)-3-去乙烯基脱镁叶绿酸甲酯,选择适当的条件,通过Grignard反应合成了对应的3-(2-羟基烷基)-3-去乙烯基脱镁叶绿酸甲酯.实验结果表明3-(2-氧代乙基)-3-去乙烯基脱美叶绿酸甲酯和Grignard试剂的反应,只要反应条件控制得当,132-位的甲氧甲酰基不会脱去.结合E环的改造,将其转变成酸酐环进而转变成N-取代的酰亚胺环.目标化合物的合成也可以将3-(2,2-二甲氧基乙基)-去乙烯基脱镁叶绿酸甲酯转变成N-取代的酰亚胺后,再和Grignard试剂反应,完成目标化合物的合成.合成的一系列化合物具有长波长的紫外吸收.化合物的结构变化对紫外吸收的影响作了相应的讨论.合成的新化合物均由核磁共振、红外光谱、元素分析予以证实.
A series of novel purpurin-18 imide derivatives which had long wavelength absorption, were synthesized by modification of methyl pheophorbide-alpha. The 3-(2,2-dimethoxyethyl)-3-devinyl methyl pheophorbide-a was prepared by oxidation of methyl pheophorbide-alpha (MPa) with Tl(NO3)(3) and transformed to 3-(2-oxo-ethyl)-3-devinyl methyl pheophorbide-alpha with formic acid. The Grignard reaction of the formyl group at 3-position was carried out to give efficiently the corresponding 3-(2-hydroxylalkyl)-3-devinyl methyl pheophorbide-alpha. In basic conditions E-ring was converted into the six-membered cyclic anhydride to form purpurin-18 derivatives by the air-oxidation. The experimental results showed that 13(2)-methyloxy-carbonyl group of methyl pheophorbide-alpha was not destroyed in the process of Grignard reaction. The spectral data of H-1 NMR of the compounds showed that there were two methoxy groups in the molecule after Grignard reaction. It was possible to modify 3-vinyl by Grignard reaction and then transform E-ring as long as controlling reaction conditions. The title compounds were synthesized by transforming E-ring to imide-ring and then modifing 3-vinyl by Grignard reaction. They demonstrated a considerable bathochromic shift of the major absorption band in the red region of the optical spectrum. The effect on their visible spectrum by variation of chemical construction was discussed. The structures of all new compounds were characterized by elemental analysis, UV, IR and H-1 NMR spectra.
出处
《有机化学》
SCIE
CAS
CSCD
北大核心
2005年第3期319-326,共8页
Chinese Journal of Organic Chemistry
基金
江苏省高校自然科学指导计划(No.03KJD350025)资助项目.
