Unprecedented Vilsmeier formylation: expedient syntheses of the cruciferous phytoalexins sinalexin and brassilexin and discovery of a new heteroaromatic ring system.
[reaction: see text]. 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.
Pedras
M S
MS
Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon SK, S7N 5C9 Canada. soledade.pedras@usask.ca
Zaharia
I L
IL
D000641:Ammonia / Q000737:chemistry; D000890:Anti-Infective Agents / Q000138:chemical synthesis*; D000935:Antifungal Agents / Q000138:chemical synthesis; D005561:Formates / Q000737:chemistry; D007211:Indoles / Q000138:chemical synthesis*; D008956:Models, Chemical; D010936:Plant Extracts / Q000138:chemical synthesis*; D012717:Sesquiterpenes; D013729:Terpenes; D013844:Thiazoles / Q000138:chemical synthesis*; D013871:Thiones / Q000138:chemical synthesis; D000094162:Phytoalexins
D000890:Anti-Infective Agents; D000935:Antifungal Agents; D005561:Formates; D007211:Indoles; D010936:Plant Extracts; D012717:Sesquiterpenes; D013729:Terpenes; D013844:Thiazoles; D013871:Thiones; C430120:sinalexin; C430121:brassilexin; D000641:Ammonia; D000094162:Phytoalexins