Anodic Oxidation of Catechols in the Presence of 1,3-Indandione. A Green Electrosynthetic Approach to New Catechol Derivatives
作者:Jahan-Bakhsh Raoof、Abolfazl Kiani、Reza Ojani、Mohammad A. Khalilzadeh
DOI:10.1246/bcsj.80.1573
日期:2007.8.15
Efficient carbon–carbon bond-forming reaction at the 5- and 6-positions of catechol skeleton was achieved through anodic oxidation of catechol, 3-methylcatechol, and 4-methylcatechol in the presence of 1,3-indandione as a nucleophile. The electrochemical synthesis was carried out in aqueous solution, which is a green solvent, using cyclic voltammetry and controlled-current coulometry techniques. The results indicate that the electrogenerated benzoquinone from the electrooxidation of the corresponding catechol participates in a Michael addition reaction with 1,3-indandione. The mechanism of anodic oxidation was deduced from voltammetric and spectroscopic data. The galavanostatic electrochemical synthesis of compounds 2a, 2b, and 2c was successfully performed in an undivided cell in good yield. The products were characterized by 1H NMR, 13C NMR, DEPT, FT-IR, and mass spectrometry.
在 1,3-indandione 作为亲核剂的存在下,通过阳极氧化儿茶酚、3-甲基邻苯二酚和 4-甲基邻苯二酚,在儿茶酚骨架的 5 位和 6 位上实现了高效的碳碳键形成反应。电化学合成是在水溶液(一种绿色溶剂)中进行的,采用了循环伏安法和可控电流库仑计技术。结果表明,相应儿茶酚电氧化生成的苯醌与 1,3-茚二酮发生了迈克尔加成反应。根据伏安法和光谱数据推断出了阳极氧化的机理。化合物 2a、2b 和 2c 的半固态电化学合成在不分流电池中成功进行,收率良好。这些产物通过 1H NMR、13C NMR、DEPT、傅立叶变换红外光谱和质谱进行了表征。