Lissodendrins A and B: 2‐Amino­imidazole Alkaloids from the Marine Sponge Lissodendoryx (Acanthodoryx) fibrosa

Abstract

Chemical investigatio n of the Indonesian sponge Lissodendoryx (Acanthodoryx) fibrosa yielded the new 2‐aminoimidazole alkaloids lissodendrins A (1) and B (2). Their structures were unambiguously determined by extensive NMR spectroscopic (1H, 13C, ROESY and long‐range HMBC) studies and mass spectrometric (HRESIMS/MS) data. Lissodendrins A (1) and B (2) possess unprecedented skeletons with the latter compound bearing a (p‐hydroxyphenyl)glyoxal moiety, which is rarely encountered in natural products. A plausible biosynthetic pathway for these new metabolites is proposed.

Efficient Total Synthesis of Lissodendrin B, 2-Aminoimidazole Marine Alkaloids Isolated from Lissodendoryx (Acanthodoryx) fibrosa

“…Thus, we completed the first total synthesis of Lissodendrin B in ten steps with an overall yield of 1.1%. Spectra of the synthesized Lissodendrin B were in excellent agreement with that of the natural product [16].…”

“…Lissodendrin A and Lissodendrin B possess unprecedented 2-aminoimidazole skeletons with the latter compound bearing a (p-hydroxyphenyl) glyoxal moiety, which is rarely encountered in natural products. The new natural alkaloid 11 is devoid of cytotoxicity to the L5178Y mouse lymphoma cell line at a dose of 10 µg/mL [16]. The precedent of diverse biological activity of 2-aminoimidazole alkaloids, coupled with the lack of synthetic methods available to date, argues well for its synthesis to support further biological evaluation.…”

“…All the compounds thus synthesized were fully characterized by 1 H, 13 C, and HRMS. new natural alkaloid 11 is devoid of cytotoxicity to the L5178Y mouse lymphoma cell line at a dose of 10 μg/mL [16]. The precedent of diverse biological activity of 2-aminoimidazole alkaloids, coupled with the lack of synthetic methods available to date, argues well for its synthesis to support further biological evaluation.…”

Marine natural products

“…(900 and 901). 438 Although inactive in anticancer, antibacterial and antifungal screens, unlike other members of the series, 15 0 -oxoadenosceptrin 902 and decarboxyagelamadin C 903 (Agelas sceptrum) are chemically interesting. Like many other congeners, these compounds are highly hydrogen decient and hence the use of 1 H-13 C and 1 H- 15 N HMBC experiments were of limited utility for structural elucidation.…”

Marine Natural Products from Indonesian Waters

“…Lissodendrins A ( 483 ) and B ( 484 ) (Figure 28A, Figure S15), 2-amino imidazole alkaloids, were isolated from the sponge Lissodendoryx ( Acanthodoryx ) fibrosa collected off Ambon, MLU [81]. The latter compound contains a ( p -hydroxyphenyl)glyoxal moiety as an unprecedented skeleton.…”