Md. Unson et al., NEW POLYCHLORINATED AMINO-ACID DERIVATIVES FROM THE MARINE SPONGE DYSIDEA-HERBACEA, Journal of organic chemistry, 58(23), 1993, pp. 6336-6343
A new series of polychlorinated amino acid derivatives were isolated f
rom the tropical marine sponge Dysidea herbacea (Dictyoceratida). Two
major hexachlorinated metabolites, dysideathiazole (4) and N-methyldys
ideathiazole (5), and a minor pentachlorinated compound, 10-dechloro-N
-methyldysideathiazole (6), were isolated from a specimen from Pohnpei
. 10-Dechlorodysideathiazole (7) was isolated as a minor constituent o
f a Palauan specimen, together with the major metabolites 9,10-didechl
oro-N-methyldysideathiazole (8) and 10-dechloro-N-methyldysideathiazol
e (6). A second specimen from Palau contained dysideapyrrolidone (9).
The structures of 4-9 were elucidated by spectroscopic methods. The ab
solute stereochemistry of compounds 4-6 was determined by X-ray crysta
llography of the natural products and of the carbamate derivative 17 t
o be S at all chiral centers.