Carbamate derivatives and sesquiterpenoids from the South China Sea gorgonian Melitodes squamata

Five carbamate derivatives, obtucarbamates C and D (1, 2), dimethyl ((carbonylbis(azanediyl))bis(2-methyl-5,1-phenylene))dicarbamate (3), obtucarbamates A and B (4, 5), and four aromadendrane-type sesquiterpenoids, (+)-4 beta-N-methenetauryl-10 beta-methoxy-1 beta,5 alpha,6 beta,7 beta-aromadendrane (6), (-)-4 beta-N-methenetauryl-10 beta-methoxy-1 beta,5 beta,6 alpha,7 alpha-aromadendrane (7), (-)-4 alpha,10 beta-aromadendranediol (8), (+)-4 beta,10 beta-aromadendranediol (9) were obtained from the South China Sea gorgonian coral Melitodes squamata Nutting. Compounds 1, 2, 6, and 7 were new, and their structures were established by spectroscopic analyses. Compounds 6 and 7 contained a taurine group that was rarely found in marine natural compounds, and 7 showed moderate antibacterial activity. The possible biosynthesis routes of 1-5 were conjectured.