New Carbazole Alkaloids from Murraya euchrestifolia HAYATA

Five new monomeric carbazoles, named eustifoline-A (1), -B (2), -C (3), and -D (5) and furostifoline (6), and one dimeric carbazole alkaloid, murrastifoline-E (7), were isolated from the root bark of Murraya euchrestifolia collected in Taiwan in December, and their structures were elucidated by spectrometric means. Eustifoline-A (1) and -B (2) have a substituted pyran ring, ad eustifoline-C (3) having a geranyl side chain is considered to be a biogenetic precursor of 2. Eustifoline-D (5) and furostifoline (6) both have a furan ring system and were shown to be structural isomers. The new dimeric carbazole murrastifoline-E (7) was found to have the structure corresponding to deoxygenated murrastifoline-D (8) and to be an adduct of murrayafoline-A (9) with girinimbine (10).