Miscellaneous Halogenated Alkaloids

The Okinawan ascidian Lissodinum sp. produces the cytotoxic diterpene alkaloids haterumaimides J (99) and K (100) [86[. The incredibly prolific cyanobacterium Lyngbya majuscula has furnished the quinoline alkaloid 101 [87[. The new quinolones 102 and 103 were isolated from the sponge Hyrtios erecta [26[. 

Several note vorthy halogenated terrestrial alkaloids are known, with epibatidine (104) at the top of the list [88]. This apparent frog Epipedobates tricolor) metabolite has powerful analgesic activity [89] and an intensive search is underway for a clinically useful drug [90]. A few chlorinated plant alkaloids have also been discovered. Romucosine F (lOS) is present in Annora purpurea, a South American bushy tree [91], and the closely related romucosine B (106) is found in the stems of RolUnia mucosa [92]. The furoquinoline alkaloid chlorodesnkolbisine (107) was isolated from the African folk medicine plant Teclea nobilis [93]. The authors of this latter study provide convincing evidence that 107 is not an isolation artifact (e.g. from the corresponding epoxide with HCl). 

Root cultures of Menispermum dauricum DC. have yielded several chlorinated alkaloids, the most recent of which are dauricumine (108) and dauricumidine (109) [94,95]. The tetrahydroquinoline alkaloid virantmycin (110) is produced by Strepto-myces nitrosporeus [96,97], as is benzastatin C (111) [98]. 

---