CHARACTERIZATION OF NEUROPROTECTIVE CARBOXYFULLERENES

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。羧基富勒烯的合成涉及两个反应：(1)丙二酸酯的加成得到加合物的混合物，用色谱法分离；(2)酯转化为酸。我们用二甲基、二乙基和二丁基丙二酸酯制备了酯，并证实了产品分布高度依赖于R基团的大小、二甲基C3、二乙基C3、二丁基C3的产率。质谱（FAB+）证实了添加的数量，但所有同分异构体的谱几乎相同。C3酯（甲基或乙基）转化成酸，得到的酸混合物都保持C3对称。鉴定出三种主要成分为六酸和两种同分异构体五酸。在不完全反应混合物的未水解部分中发现了五酯，这表明羧基在水解之前丢失了。各种质谱技术被用来表征产物和副产物。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Carboxyfullerene synthesis involves two reactions (1) addition of esters of malonic acid to give mixtures of adducts which are separated by chromatography and (2) conversion of esters to acids. We have prepared esters using dimethyl, diethyl and di-t-butyl malonates and confirmed that the product distribution is highly dependent on the size of the R group, yield of dimethyl C3 diethyl C3 di-t-butyl C3. The mass spectra (FAB+) confirmed the number of additions but the spectra were nearly identical for all isomers. Conversion of C3 esters (methyl or ethyl) to acid gave mixtures of acids which all retained the C3 symmetry. The three major components were identified as hexa acid and two isomeric penta acids. Penta esters were found in the unhydrolyzed portion of an incomplete reaction mixture, suggesting that the carboxyl was lost prior to hydrolysis. A variety of mass spectrometric techniques are used to characterize products and byproducts.