New Coumarins from Some Citrus Plants

Six new coumarins, 6-formylumbelliferone (1), hassanon (2), 5-hydroxyseselin (4), cis-grandmarin (6, cis), trans-grandmarin isovalerate (8, trans), and kinocoumarin (9), were isolated from roots and root barks of some Citrus plants, and their structures were determined by means of spectral and chemical studies.