二氢卟吩P6醚类衍生物的合成

以蚕沙糊状叶绿素经酸碱降解制得的二氢卟吩P6三甲酯(2)为关键中间体,设计合成了9个二氢卟吩P6醚类衍生物3a～3e和4b～4e,用UV、IR、^1H、NMR、FAB-MS和元素分析确证了它们的结构。     

二氢卟吩e~6-6-酰胺衍生物的合成

首次报道了以蚕沙叶绿素初提物为基础原料,经酸降解得到含焦脱镁叶绿酸a和脱镁叶绿酸a的混合物,不经分离直接与胺类反应使脱镁叶绿酸a的戊酮环(V)裂开,合成得11种二氢卟吩e~6-6-酰胺衍生物。提供了一种合成二氢卟吩酰胺的新方法。     

叶绿素-a降解产物的酰基化反应及其二氢卟吩衍生物的合成

以脱镁叶绿酸-a甲酯(MPa)为起始原料,经化学结构修饰和中心氮原子金属化后,与三氯氧磷/3-N,N-二甲基氨基丙烯醛(3-DMA)或者N,N-二甲基甲酰胺进行Vilsmerier反应,在二氢卟吩周环上区域选择性地引进甲酰基或者甲酰乙烯基;用硝酸铊对MPa衍生物实施氧化,将3-位乙烯基顺利地转化为甲酰甲基;利用3-位乙烯基和E-环酮基的化学反应活性,在大环上引进羟烷氧基或者羟烷氨基结构,然后选用高钌酸四丙基铵(TPAP)和N-甲基吗啉-N-氧化物混合氧化剂,分别将其羟基氧化成甲酰基.新合成的连有酰基结构的二氢卟吩衍生物的化学结构均经UV,IR,1H NMR及元素分析得以证实.     

具有氮杂环并叶绿素色基结构的二氢卟吩衍生物的合成

采用一锅法从叶绿素-a制得132-氧代焦脱镁叶绿酸-a甲酯,再与邻苯二胺反应生成四种含氮杂环并二氢卟吩衍生物,再经硝酸铊或者四氧化锇氧化将其3-位乙烯基转化成高反应性的甲酰基和甲酰甲基.C3-甲酰甲基与邻氨基苯甲醛的Friedl nder缩合顺利地环合成喹啉结构,与重氮甲烷和氧化苯甲腈的1,3-偶极环加成反应在3-位上构建了五元杂环.首次报道的具有叶绿素基本碳架的二氢卟吩衍生物的化学结构均经UV,IR,1H NMR及元素分析得以证实.     

叶绿素-a及其降解产物的化学修饰与二氢卟吩醇类衍生物的合成

以叶绿素-a为基本原料,在酸性条件下一锅法完成脱金属、酯交换、空气氧化和重排反应,以不同的产率生成多种叶绿素-a的降解和氧化产物.通过加成、氧化和还原反应,对其主要降解产物脱镁叶绿酸-a甲酯和焦脱镁叶绿酸-a甲酯的3-位乙烯基和E-环羰基实施化学修饰,在叶绿素-a基本碳架的不同位置上引进羟基,完成9种未见报道的二氢卟吩醇类衍生物的合成.所合成的新化合物均经UV,IR,1HNMR及元素分析证明其结构.     

叶绿素降解产物的环丙基化及其二氢卟吩衍生物的合成

以叶绿素降解产物脱镁叶绿酸-a甲酯为起始原料,利用其二氢卟吩大环上的活性反应区域,沿着N21-N23轴向进行官能团修饰,通过1,3-偶极环加成反应、Grignard反应和外接环的结构改造,在周环上的不同位置上引进了三元环烷基结构,完成了一系列未见报道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,MS及元素分析予以证实,同时也讨论了环丙基的引进对二氢卟吩的理化性质所产生的各种影响,并对部分新化合物的体外光动力活性进行了测试.     

多酯基取代的叶绿素类二氢卟吩衍生物的合成

以脱镁叶绿酸-a甲酯为起始原料,通过碱性条件下的水解开环、空气氧化和重排反应,分别合成了红紫素-7三甲酯和二氢卟吩-p6三甲酯.然后对其C(3)-乙烯基、20-meso-位、12-位甲基以及尾端酯基进行化学修饰,通过亲电加成、亲电取代、1,3-偶极环加成和氧化重排等反应,完成10种具未见报道的的叶绿素类二氢卟吩衍生物,其化学结构均经UV,IR,1H NMR光谱及元素分析予以表征.     

周环上芳基取代的叶绿素类二氢卟吩衍生物的合成

以叶绿素降解产物脱镁叶绿酸-a甲酯为起始原料,利用其二氢卟吩大环上的活性反应区域,沿着N21-N23轴向进行官能团修饰,对五元外接E-环也实施了结构改造,在周环上分别引进了能与大环色基形成不同共轭程度的芳香性取代基团,完成了12个未见报道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和质谱及元素分析予以证实,同时也讨论了芳基的引进对二氢卟吩的理化性质所产生的各种影响.     

具有立体异构特征的叶绿素类二氢卟吩衍生物的合成

以脱镁叶绿酸-a甲酯为起始原料,利用周环上的碳碳、碳氧和烯醇式复健,通过加成、取代、缩合和空气氧化等化学反应在色基上构建手性中心、顺反结构和阻旋位点.经过旨在扩大立体差异的化学修饰,对部分差向异构体进行了有效分离,完成一系列具有立体异构特征的叶绿素衍生物的合成,并通过UV,IR,1H NMR及元素分析证实了11个未见报道的二氢卟吩衍生物的化学结构,同时对不同立体异构的形成及其表征进行了讨论.     

叶绿素降解产物的羟(烷)基化及其二氢卟吩衍生物的合成

以脱镁叶绿酸-a甲酯为起始原料,利用二氢卟吩大环上的富电子区域的化学反应性对其实施结构修饰,通过外接E环α-氢的空气氧化、C(3)-乙烯基的亲电加成、羰基的亲核加成和20-meso-氢的亲电取代反应,在外接E环、C(3)-,C(12)-β-位和20-meso-位上完成了羟基或者羟烷基的引进,新建羟基的氧化和脱水反应进一步转换成碳氧双键或者碳碳双键.所合成的11个未见报道的叶绿素类二氢卟吩衍生物的化学结构均经UV,1H NMR,IR及元素分析得以证实,对相应的化学反应提出了可能的反应机理.     

HPLC study of chlorin e6 and its molecular complex with polyvinylpyrrolidone

Several HPLC methods with UV detection were developed for qualitative and quantitative analysis of chlorin e(6) and photosensitizer Photolon either in the free form or upon pre-derivatization (methylation) under reversed- and normal-phase conditions. Optimum analysis conditions providing the best resolution of analytes were found at acidic pH where polar groups are completely protonated. The separation was performed by gradient elution with mobile phases of 0.08% trifluoroacetic acid and acetonitrile on an XTerra RP(18) column. The method was specific, accurate and precise, allowing the analysis of chlorin e(6) in the presence of numerous degradation products useful in the manufacturing process and quality control of chlorin e(6) and Photolon.     

Novel types of boronated chlorin e6 conjugates via ‘click chemistry’

Conjugates of chlorin e₆ with closo‐dodecaborate and cobalt bis(dicarbollide) anions were synthesized for the first time in high yields using the advanced ‘click’ methodology. In vitro study on A549 human lung adenocarcinoma cells revealed that the synthesized boronated conjugates are able to penetrate and accumulate in cancer cells, but their intracellular concentration is not sufficient for effective photodynamic and boron neutron capture therapy of cancer. Copyright © 2009 John Wiley & Sons, Ltd.     

HPLC separation and characterization of chlorin derivatives with intact ring V from acid degradation products of silkworm excrement crude chlorophyll mixture

A reversed-phase HPLC system with 88% methanol in 1 M ammonium acetate buffer pH 5.35 as the mobile phase on an ODS column was used to analyse pheophorbides a, a', b, b' and pyropheophorbides a and b. Pyropheophorbides a and b were found in samples obtained from silkworm excrement but not from spinach leaves though the preparation methods used were the same. This difference suggests that chlorophylls undergo metabolism in the body of silkworm to give pyrochlorophyll derivatives.     

Chlorin e6-Biotin Conjugates for Tumor-Targeting Photodynamic Therapy

To improve the tumor-targeting efficacy of photodynamic therapy, biotin was conjugated with chlorin e6 to develop a new tumor-targeting photosensitizer, Ce6-biotin. The Ce6-biotin had good water solubility and low aggregation. The singlet-oxygen generation rate of Ce6-biotin was slightly increased compared to Ce6. Flow cytometry and confocal laser scanning microscopy results confirmed Ce6-biotin had higher binding affinity toward biotin-receptor-positive HeLa human cervical carcinoma cells than its precursor, Ce6. Due to the BR-targeting ability of Ce6-biotin, it exhibited stronger cytotoxicity to HeLa cells upon laser irradiation. The IC50 against HeLa cells of Ce6-biotin and Ce6 were 1.28 µM and 2.31 µM, respectively. Furthermore, both Ce6-biotin and Ce6 showed minimal dark toxicity. The selectively enhanced therapeutic efficacy and low dark toxicity suggest that Ce6-biotin is a promising PS for BR-positive-tumor-targeting photodynamic therapy.     

Design and synthesis of novel water-soluble amino acid derivatives of chlorin p6 ethers as photosensitizer

Eight new water-soluble amino acid derivatives of chlorin p₆ ethers 6a-h were designed and synthesized using purpurin-18 (2) as key intermediate. All target compounds exhibited better phototoxicity than talaporfin and the most phototoxic compound 6d showed IC₅₀ values of 0.20 μmol/L against A549 cell and 0.41 μmol/L against B16-F10 cell, which represented 31- and 24-fold increase of PDT antitumor efficacy compared to talaporfin.     

Synthesis of cationic water-soluble esters of chlorin e6

Two esters of chlorin e₆ have been synthesized by esterification with aminoalcohols via the formation of acid chloride using oxalyl chloride and converted to the corresponding cationic water-soluble esters of chlorin e₆. The visible absorption and circular dichroism spectra have revealed that these two cationic chlorin e₆ esters synthesized are readily soluble in water as a monomer.     

Highly enhanced phototoxicity of chlorin e6‐conjugated poly(β‐cyclodextrin) with gas forming capacity at an acidic tumor extracellular pH and its in vitro evaluation

In this study, we report a novel polysaccharidic drug conjugate consisting of poly(β‐cyclodextrin) [poly(β‐CD)] with gas‐forming carbonate linkages resulting from the chemical coupling of the hydroxyl groups of poly(β‐CD) and cholesteryl chloroformate (CC) and a photosensitizing drug (chlorin e6: Ce6). This drug conjugate was self‐assembled in aqueous solution leading to the production of nanoparticles containing the poly(β‐CD) on the hydrophilic outer shell and CC and Ce6 in the hydrophobic inner core. Cleavage (i.e. the detachment of CC moieties) of the carbonate linkage at a slightly acidic pH (~pH 6.5) produced carbon dioxide bubbles. More specifically, the nanoparticles (with autoquenched Ce6 molecules in their core at pH 7.4) were destabilized at pH 6.5, thereby dequenching the Ce6 molecules. These experimental results demonstrate that under light illumination the nanoparticles increased singlet oxygen generation at pH 6.5 compared to pH 7.4 and exhibited a higher phototoxicity for KB tumor cells at pH 6.5 compared to pH 7.4. This approach represents an effective photodynamic therapy for acidic tumors. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis and antiproliferative activity of new chlorin e6 glycoconjugates

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