Spectrometric elucidation of acrimarines, the first naturally occurring acridone–coumarin dimers

The structures of acrimarine-A (1), -B (2), -C (3), -D (4), -E (5), -F (6), and -G (7), novel acridone alkaloids carrying a coumarin unit, from the root of Citrus funadoko have been elucidated by spectrometric studies using 1H-13C long-range COSY experiments; acrimarine-A (1) and -F (6) have also been synthesized from the corresponding acridones and coumarins.