Functionalized 1,2-Dioxetanes as Potential Chemotherapeutic Agents: The Synthesis of Dioxetane-Substituted Carbamates
作者:Waldemar Adam、Vidya Bhushan、Thomas Dirnberger、Rainer Fuchs
DOI:10.1055/s-1986-31604
日期:——
Despite their labile nature1, 1,2-dioxetanes can be chemically transformed under mild conditions thereby permitting chemical functionalization of these biologically potentially useful substances. For example, it was possible to show2 that the hydroxydioxetane 1 3 can be converted in high yields into carboxylic esters using such gentle methods as the Brewster-Ciotti and Mitsunobu esterifications. In these cases, the nucleophilic hydroxy group of the dioxetane can be conveniently derivatized with electrophilic biomolecules, e. g. fatty acids. A broader scope would be achieved, if nucleophilic biomolecules could be attached to dioxetanes. In this manner dioxetane-substituted sugars, steroids, pyrimidine bases, peptides, etc. could be made available as potential chemotherapeutic agents. In principle two synthetic approaches can be pursued to accomplish such derivatization. In the case of amines, the carbamate linkage is a logical choice to bind such nucleophiles to the nucleophilic hydroxydioxetane 1. Either the nucleophilic hydroxydioxetane 1 is transformed into the electrophilic carbonochloridate 2 and subsequently converted to the carbamates 3 (Scheme), or the nucleophilic amine is transformed into the electrophilic isocyanate and subsequently treated with the hydroxydioxetane 1. Presently we report that both synthetic sequences are feasible for derivatizing the hydroxydioxetane 1, leading to the carbamates 3 in good yields. The results are summarized in the Table.
尽管 1,2-二氧杂环丁烷具有易变性1 ,但可以在温和的条件下进行化学转化,从而使这些具有生物潜在用途的物质发生化学功能化。例如,有研究表明2 ,羟基二氧杂环丁烷 1 3 可以通过布儒斯特-西奥蒂酯化法和三忍酯化法等温和的方法高产率地转化为羧酸酯。在这些情况下,二氧杂环丁烷的亲核羟基可方便地与亲电生物分子(如脂肪酸)进行衍生。如果二氧杂环丁烷上可以连接亲核生物分子,则可以实现更广泛的应用。这样,二氧杂环丁烷取代的糖、类固醇、嘧啶碱、肽等就可以作为潜在的化疗药物。 原则上,可以采用两种合成方法来实现这种衍生化。就胺类而言,氨基甲酸酯连接是将这类亲核物与亲核羟基二氧杂环丁烷 1 结合的合理选择。要么将亲核的羟基二氧杂环丁烷 1 转化为亲电的氯代碳酸酯 2,然后再转化为氨基甲酸酯 3(方案),要么将亲核胺转化为亲电的异氰酸酯,然后再与羟基二氧杂环丁烷 1 一起处理。目前,我们的报告显示,这两种合成顺序都可以衍生羟基二氧杂环丁烷 1,并以良好的收率得到氨基甲酸酯 3。结果汇总于表中。