Synthesis of Linear Pyranocoumarins: Xanthoxyletin, 4-Methylxanthyletin, and 4-Phenylxanthyletin

Article abstract of DOI:10.1246/bcsj.53.1070

A convenient synthesis of linear pyranocoumarins (2H,8H-benzo<1,2-b: 5,4-b'>dipyran-2-ones), viz., xanthoxyletin, 4-methylxanthyletin and 4-phenylxanthyletin is described which uses blocking the 8-position of appropriate 7-hydroxycoumarin derivatives with iodine and 1,1-dimethyl-2-propynylation followed by cyclisation.