Abstract
Separation of a lipophilic extract of the bryozoan,Dakaira subovoidea, a common fouling organism of underwater structures, guided by inhibition of lipid peroxide formation in rat liver microsomes, gave 5,7-dihydroxy-1-hydroxymethyl-6-oxo-6H-anthra[1,9-bc]thiophene (1a) and its 1-methoxycarbonyl derivative (1c), together with the known 1,8-dihydroxyanthraquinone (2). The structures were determined by spectral and crystallographic analyses.
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Sato, A., Shindo, T., Kasanuki, N., and Hasegawa, K., J. nat. Prod.52 (1989) 975.
1a:13C NMR [67.7 MHz, δ (d5−Py)] 61.1 (t), 111.2 (s), 115.0 (s), 115.4 (s), 115.8 (d), 117.6 (d), 120.7 (s), 126.6 (s), 131.9 (d), 136.5 (d), 138.8 (s), 160.2 (s), 164.5 (s), 191.2 (s). UV [λ max nm (ɛ, EtOH)] 220 (24700), 231 (23100), 244 (sh) (13800), 285 (8400), 327 (4500), 366 (4500), 392 (sh) (7200), 420 (9000), 434 (9800). IR [v max cm−1 (nujol)] 3480, 1630, 1605, 1220, 1050, 830, 780. EIMS [m/z (%)] 298 (100), 281 (31), 265 (55).
1b:1H NMR [270 MHz, δ (CDCl3)] 2.24 (3H, s), 2.48 (3H, s), 2.49 (3H, s), 5.79 (2H, s), 7.19 (1H, dd, J=1.9, 7.8 Hz), 7.27 (1H, d, J=8.3 Hz), 7.73 (1H, t, J=7.8 Hz), 7.79 (1H, dd, J=1.9, 7.8 Hz), 8.07 (1H, d, J=8.3 Hz).13C NMR [67.7 MHz, δ (CDCl3)] 20.7 (q), 21.25 (q), 21.31 (q), 61.2 (t), 119.8 (s), 121.9 (d), 123.8 (2×d), 127.9 (d), 133.8 (s), 134.6 (2×d), 139.1 (s), 143.2 (2×s), 149.2 (2×s), 152.3 (s), 169.6 (s), 170.1 (s), 180.7 (s). UV [λ max nm (ɛ, EtOH)] 213 (42800), 232 (sh) (25700), 240 (sh) (21700), 262 (sh) (13800), 282 (15300), 302 (sh) (9200), 352 (sh) (6700), 390 (12200). IR [v max cm−1 (CHCl3)]1752, 1640, 1600, 1580, 1360, 1200. EIMS [m/z (%)] 427 (27), 382 (60), 340 (100), 298 (50), 281 (60), 269 (30).
1c:1H NMR [270 MHz, δ (CDCl3)]4.05 (3H, s), 7.12 (1H, dd, J=1.0, 8.3 Hz), 7.28 (1H, d, J=8.8 Hz), 7.68 (1H, t, J=8.3 Hz), 8.02 (1H, d. J=8.8 Hz), 8.88 (1H, dd, J=1.0, 8.3 Hz), 12.35 (1H, s), 13.21 (1H, s). IR [v max cm−1 (CHCl3)] 1720, 1626, 1605, 1575, 1480, 1440, 1378, 840. EIMS [m/z (%)] 326 (100), 295 (33), 268 (18), 267 (13). UV [λ max nm (ε, EtOH)] 228 (24000), 336 (6400), 377 (sh) (4000), 395 (6400), 443 (8600), 459 (sh) (8400).
Crystal data of1a: monoclinic, space group P21/a, Z=4, lattice constants a=19.043 (1), b=9.9226 (7), c=6.6988 (9) Å, β=104.31 (1)o (1), Dc=1.62 g/cm3, V=1226.5 (2) Å3.
Krollpfeiffer F., Schneider, K. L., and Wissner, A., Ann.566, 139.
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Shindo, T., Sato, A., Kasanuki, N. et al. 6H-anthra[1,9-bc]thiophene derivatives from a bryozoan,Dakaira subovoidea . Experientia 49, 177–178 (1993). https://doi.org/10.1007/BF01989426
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DOI: https://doi.org/10.1007/BF01989426