脱镁叶绿酸的C(17)-尾端酯基的化学反应及其二氢卟吩衍生物的合成

Chemical Reaction of C(17)-End Ester Group in Pyropheophorbide and Synthesis of Chlorin Derivatives

以焦脱镁叶绿酸-a甲酯为起始原料,通过化学修饰在五元外接环上构筑活性反应区域,经分子内的酯交换、Michael加成和Claisen缩合等经典化学反应,使得132-与17-位通过不同的碳链相互连接,在C-D环端向上形成了双环和螺环结构.同时,利用17-位尾端酯基的化学活性进行胺解和酰化反应,在二氢卟吩色基的最远端建立了不同的化学结构,完成了9个未见报道的具有新颖碳架结构的叶绿素类二氢卟吩衍生物的合成,其化学结构均经UV、IR、1H NMR及元素分析予以证实.

Pyropheophorbide-a methyl ester was used as a starting material. The active reaction regions were constructed by chemical modifications on the five-membered exocyclic ring, and the interconnections through different carbon chain between 132- and 17-position were carried out by classic reaction, such as intramolecular interesterification, Michael addition and Claisen condensation, to form bicyclic or spirocyclic structures in the side of C-D ring. The aminolysis and acylation were performed making use of chemical activity of end ester group at 17-position to establish the different chemical structures in the far end of chlorin chromophore. The syntheses of 9 unreported chlorins related to chlorophyll with novel carbon skeleton were accomplished and their chemical structures were characterized by elemental analysis, UV, IR and 1H NMR spectra.