Rhopaladins A ∼ D, new indole alkaloids from marine tunicate Rhopalaea sp

Marine Bi-, Bis-, and Trisindole Alkaloids

“…24 The methanolic extract of T. genitrix was shown to possess varying degrees of toxicity to the fish Lebistres fluviatilis and the freshwater sponge Ephydatia fluviatilis in addition to exhibiting general antibacterial properties. 24 Further chromatographic purification of this methanolic extract yielded three major bisindole imidazole metabolites, which were originally named topsentin A (42), B1 (43), and B2 (44). 24 These names were later changed to deoxytopsentin (42), topsentin (43), and bromotopsentin (44), respectively 25 (Figure 1.5).…”

“…24 Further chromatographic purification of this methanolic extract yielded three major bisindole imidazole metabolites, which were originally named topsentin A (42), B1 (43), and B2 (44). 24 These names were later changed to deoxytopsentin (42), topsentin (43), and bromotopsentin (44), respectively 25 (Figure 1.5). Bartik recognized that all three compounds exist as a mixture of slowly interconverting imidazole tautomers in neutral solution, resulting in the doubling of resonances in the 1 H and 13 C NMR spectra of these compounds.…”

“…An interesting series of imidazolinone bisindoles, rhopaladins A-D (63-66), possessing an "extra" olefinic methine moiety (C8 0 ) between the indole and the imidazolinone ring, 43 were isolated from an Okinawan ascidian Rhopalaea sp. NOE experiments revealed that these compounds exist as rotational isomers, around the C3 0 dC8 0 bond 43 (Figure 1.7).…”

Crystal structure of 3-(3-nitrophenylhydrazonocarbonyl)-(1H)-1,2,4-triazole

“…They have become the central issue focus of the study of agricultural chemicals, medicine, adjusting reagents for plant growth and so on [1][2][3]. Schiff base is a good type of biological active substructure.…”

Two New Imidazolone‐Containing Alkaloids and Further Metabolites from the Ascomycete Fungus Tricladium sp.

“…-Imidazolone-containing metabolites have been previously reported, such as the kottamides from an ascidian Pycnoclavella kottae [19] and the rhopaladins from a marine tunicate Rhopalaea sp. [22]. Tricladins A and B (1 and 2, resp.)…”