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T. Janosik et al. / Tetrahedron 58 32002) 2813±2819
1
mp 299.0±300.58C; IR 4KBr) 3356, 3218, 1683, 1623, 1494,
741 cm21; H NMR 4DMSO-d6) d 12.31 4br, 2H), 11.74
4br s, 1H), 9.05 4s, 1H), 8.48 4br, 2H), 8.35±8.32 4m, 1H),
7.66 4s, 1H), 7.61±7.53 4m, 2H), 7.32±7.22 4m, 4H); 13C
NMR 4DMSO-d6) d 177.2 4s), 169.6 4s), 154.3 4s), 137.3 4s),
137.0 4d), 136.4 4s), 135.6 4d), 134.9 4s), 126.6 4s), 126.5 4s),
126.3 4d), 123.5 4d), 123.2 4d), 122.6 4d), 121.5 4d), 121.4
4d), 120.5 4d), 113.4 4s), 112.6 4d), 112.6 4d), 112.1 4s); MS
4ESI) m/z 353 4M2H)2; HRMS 4EI) m/z calcd for
C21H14N4O2 4M1) 354.1117, found 354.1120.
1
1445, 1416, 1351, 1264, 1140, 976, 886 cm21; H NMR
4DMSO-d6) d 12.10 4br, 2H), 11.74 4br s, 1H), 9.32 4br s,
1H), 9.03 4s, 1H), 8.44 4d, J1.9 Hz, 1H), 8.33 4br, 1H),
8.274s, 1H), 7.58 4d, J8.6 Hz, 1H), 7.57 4s, 1H), 7.42 4dd,
J8.6, 1.9 Hz, 1H), 6.88 4d, J2.1 Hz, 1H), 6.75 4dd, J
8.6, 2.1 Hz, 1H); MS 4ESI) m/z 447and 449 4M 2H)2;
HRMS 4FAB1) m/z calcd for C21H14N4O379Br 4M1H)1
449.0249, found 449.0235.
3.1.14. Rhopaladin B ,2). The procedure above was used
with compound 23a 45.0 mg, 0.013 mmol) and BBr3 in
dichloromethane 41 M, 0.16 mL, 0.16 mmol) to give rhopa-
ladin B 42) 43.0 mg, 62%) after gradient column chroma-
tography starting with ethyl acetate/hexane 470:30) with
increasing amounts of ethyl acetate. An analytically pure
sample was obtained by crystallization from MeOH,
which afforded 2 as dark red crystals: mp 239.5±241.58C;
IR 4KBr) 3251, 2426, 2292, 1676, 1622, 1593, 1509, 1499,
1326, 1227, 921 cm21; 1H NMR 4DMSO-d6) d 12.36 4br s,
1H), 11.95 4br s, 1H), 11.69 4br s, 1H), 9.31 4br s, 1H), 9.01
4s, 1H), 8.36 4br, 1H), 8.34±8.31 4m, 1H), 8.26 4s, 1H),
7.59±7.55 4m, 2H), 7.33±7.26 4m, 2H), 6.88 4d, J
2.1 Hz, 1H) 6.72 4dd, J8.6, 2.1 Hz, 1H); 13C NMR
4DMSO-d6) d 177.1 4s), 169.6 4s), 154.6 4s), 153.5 4s),
138.5 4s), 137.1 4d), 136.3 4s), 135.1 4d), 134.3 4s), 127.2
4d), 126.3 4s), 123.4 4d), 122.5 4d), 121.74d), 121.4 4d),
119.1 4s), 113.4 4s), 112.74s), 112.5 4d), 111.6 4d), 97.6
4d); MS 4ESI) m/z 369 4M2H)2; HRMS 4FAB1) m/z
calcd for C21H15N4O3 4M1H)1 371.1144, found 371.1148.
References
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3.1.15. Rhopaladin C ,3). To a solution of 21b 4100 mg,
0.30 mmol) and triethylamine 40.08 mL, 0.60 mmol) in
dioxane 48 mL) was added Trp±OMeHCl 477 mg, 0.30
mmol). The mixture was kept at 608C for 3 days, during
that period a dark red color appeared. After cooling, the
solvent was evaporated and the residue subjected to column
chromatography using ethyl acetate as eluent to yield
rhopaladin C 43) 450 mg, 38%) as a red solid. An ana-
lytically pure sample was obtained by crystallization from
MeOH, which afforded 3 as dark red crystals: mp 332.5±
333.58C; IR 4KBr) 3266, 3101, 2933, 1666, 1589, 1490,
10. Morris, S. A.; Andersen, R. Tetrahedron 1990, 46, 715.
11. Kawasaki, I.; Katsuma, H.; Nakayama, Y.; Yamashita, M.;
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1
1420, 1235, 1132, 975, 840, 747 cm21; H NMR 4DMSO-
d6) d 12.39 4br s, 1H), 12.39 4br s, 1H), 11.79 4br s, 1H), 9.07
4s, 1H), 8.49 4s, 1H), 8.49±8.45 4br s, 1H), 8.474d,
J1.9 Hz, 1H), 7.86 4s, 1H), 7.59±7.53 4m, 2H), 7.46 4dd,
J8.6, 1.9 Hz, 1H), 7.31±7.21 4m, 2H); 13C NMR 4DMSO-
d6) d 177.1 4s), 169.5 4s), 153.9 4s), 138.3 4d), 137.0 4s),
135.74d), 135.1 4s), 134.9 4s), 128.1 4s), 126.9 4d), 126.5 4s),
126.1 4d), 123.5 4d), 123.2 4d), 121.5 4d), 120.4 4d), 115.3
4s), 114.74d), 112.8 4s), 112.5 4d), 112.1 4s); MS 4ESI) m/z
431 and 433 4M2H)2; HRMS 4FAB1) m/z calcd for
C21H14N4O279Br 4M1H)1 433.0300, found 433.0292.
16. Finger, H. J. Prakt. Chem. 1907, 76, 93.
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3.1.16. Rhopaladin D ,4). The procedure above was used
with 21a 4105 mg, 0.42 mmol), triethylamine 40.12 mL,
0.83 mmol) and Trp±OMeHCl 4107mg, 0.42 mmol) to
give rhopaladin D 44) 452 mg, 35%) after column chroma-
tography using ethyl acetate as eluent. An analytically pure
sample was obtained by crystallization from MeOH, which
afforded 4 as dark red crystals: mp 315.5±317.58C 4lit.6
287±2908C); IR 4KBr) 3436, 3284, 2934, 1162, 1612,
1594, 1581, 1490, 1426, 1359, 1232, 1131, 981, 835,
È
23. Harle, H.; Jochims, J. C. Chem. Ber. 1986, 119, 1400.
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