Recently, many marine imidazole alkaloids such as 1–10 in Table 1 have been isolated from sponges, and their antitumor and antibacterial activities have also been found. 1. and 2. Structural characteristics of these alkaloids are that one or two alkoxy benzyl group(s) locates at the 1-, 4- and/or 5-positions of the 1H-imidazole ring and the 2-position is substituted with a primary amino group or a (1-methyl-2,5-dioxo-3-imidazolin-4-yl)amino moiety 2 (Table 1).
