Unprecedented Vilsmeier Formylation: Expedient Syntheses of the Cruciferous Phytoalexins Sinalexin and Brassilexin and Discovery of a New Heteroaromatic Ring System
摘要:
A very concise first synthesis of sinalexin was achieved by regioselective formylation of 1-methoxyindoline-2 thione under Vilsmeier conditions followed by unprecedented ammonia workup, Similar formylation of indoline-2-thione yielded brassilexin and a novel pentacyclic heteroaromatic compound resulting from condensation of the Vilsmeier adduct of indoline-2-thione. Both sinalexin and brassilexin displayed strong antifungal activity against several pathogens of crucifers.
Concise Syntheses of the Cruciferous Phytoalexins Brassilexin, Sinalexin, Wasalexins, and Analogues: Expanding the Scope of the Vilsmeier Formylation
作者:M. Soledade C. Pedras、Mukund Jha
DOI:10.1021/jo0479866
日期:2005.3.1
the Vilsmeierformylation to indoline-2-thiones followed by a new aqueous ammonia workup procedure. Similarly, a very concise two-pot synthesis of the phytoalexins wasalexins using sequential formylation−amination of indolin-2-ones is described. Remarkably, this novel aqueous ammonia workup allows the sequential one-pot formylation−amination, expanding substantially the scope of the Vilsmeier formylation