1678 J ournal of Natural Products, 2004, Vol. 67, No. 10
Rodr´ıguez et al.
P seu d op ter osin V (7): white powder; [R]20 -32.9° (c 1.1,
P er a cetyla tion of P seu d op ter osin s U-Y (6-10). Indi-
vidual samples of approximately 2-3 mg of each pseudopterosin
were dissolved in a 1:1 mixture of acetic anhydride-pyridine
(1 mL) and stirred at 20 °C overnight. Evaporation in vacuo
of the volatile materials followed by silica gel column chro-
matography of the oily residue isolated afforded each time the
D
CHCl3); IR (film) νmax 3363, 2964, 2929, 2863, 1746, 1445, 1377,
1247 cm-1; UV (MeOH) λmax 228 (ꢀ 22 300), 277 (ꢀ 6500), 284
1
(ꢀ 6300) nm; H NMR (500 MHz, CDCl3) and 13C NMR (125
MHz, CDCl3) (see Table 2); HRFABMS m/z [M - 1]+ 473.2339
(calcd for C27H37O7, 473.2339).
P seu d op ter osin W (8): white amorphous solid; [R]20
same triacetate 15 (average yield ) 59%): colorless viscous
D
1
-54.8° (c 1.3, CHCl3); IR (film) νmax 3351, 2948, 2924, 2857,
oil; [R]20 -107.3° (c 0.8, CHCl3); H NMR (500 MHz, CDCl3)
D
1747, 1448, 1372, 1237 cm-1; UV (MeOH) λmax 228 (ꢀ 35 000),
δ 6.78 (1H, s, C-9 OH), 5.59 (1H, dd, J ) 10.5, 3.4 Hz, H-3′),
5.47 (1H, dd, J ) 10.7, 3.2 Hz, H-2′), 5.46 (1H, br s, H-4′), 5.19
(1H, d, J ) 3.3 Hz, H-1′), 4.91 (1H, d, J ) 9.5 Hz, H-14), 4.45
(1H, d, J ) 12.5 Hz, H-5′ax), 3.90 (1H, dd, J ) 13.0, 2.4 Hz,
H-5′eq), 3.65 (1H, dd, J ) 9.6, 8.1 Hz, H-1), 3.18 (1H, m, H-7),
2.17 (3H, s), 2.16 (3H, s), 2.09 (3H, s, Me-20), 2.05 (3H, s), 1.93
(1H, m, H-2â), 1.71 (3H, br s, Me-17), 1.65 (3H, br s, Me-16),
1.32-1.23 (2H, m, H-6â, H-3), 1.23 (3H, d, J ) 6.7 Hz, Me-
19), 1.02 (3H, d, J ) 6.0 Hz, Me-18), 0.91 (1H, m, H-5R); 13C
NMR (75 MHz, CDCl3) δ 170.3 (s, -COCH3), 170.0 (s,
-COCH3), 169.5 (s, -COCH3), 144.5 (s, C-9), 142.9 (s, C-10),
136.8 (s, C-13), 131.0 (d, C-14), 129.9 (s, C-12), 128.4 (s, C-15),
127.3 (s, C-11), 126.6 (s, C-8), 101.5 (d, C-1′), 68.6 (d), 68.0 (d),
67.0 (d), 61.9 (t, C-5′), 44.7 (d, C-4), 40.1 (t, C-2), 37.3 (d, C-1),
33.8 (d, C-3), 31.9 (t, C-6), 28.5 (d, C-7), 27.8 (t, C-5), 25.4 (q,
C-16), 23.1 (q, C-19), 20.9 (q, COCH3), 20.7 (q, COCH3), 20.6
(q, COCH3), 20.0 (q, C-18), 17.5 (q, C-17), 14.0 (q, C-20);
LRESIMS m/z (M + H)+ 559.
1
277 (ꢀ 13 000), 284 (ꢀ 9000) nm; H NMR (500 MHz, CDCl3)
and 13C NMR (125 MHz, CDCl3) (see Table 2); HRESIMS m/z
[M + 1]+ 517.2795 (calcd for C29H41O8, 517.2801).
P seu d op ter osin X (9): light yellow oil; [R]20D -39.0° (c 1.3,
CHCl3); IR (film) νmax 3477, 2958, 2928, 2858, 1743, 1450, 1372,
1233 cm-1; UV (MeOH) λmax 228 (ꢀ 33 800), 277 (ꢀ 6800), 284
1
(ꢀ 5100) nm; H NMR (500 MHz, CDCl3) and 13C NMR (125
MHz, CDCl3) (see Table 3); HRFABMS m/z [M + Na]+
539.2614 (calcd for C29H40O8Na, 539.2621).
P seu d op ter osin Y (10): white powder; [R]20D -54.2° (c 1.0,
CHCl3); IR (film) νmax 3363, 2962, 2925, 2868, 1452, 1376, 1238,
1083 cm-1; UV (MeOH) λmax 228 (ꢀ 28 400), 278 (ꢀ 7500), 284
1
(ꢀ 6800) nm; H NMR (500 MHz, CDCl3) and 13C NMR (125
MHz, CDCl3) (see Table 3); HRESIMS m/z [M + 1]+ 433.2590
(calcd for C25H37O6, 433.2590).
P seu d op ter osin Z (11): white powder; [R]20 -142.6° (c
D
0.9, CHCl3); IR (film) νmax 3343, 2947, 2924, 2868, 1747, 1451,
1430, 1374, 1237 cm-1; UV (MeOH) λmax 228 (ꢀ 21 700), 277 (ꢀ
18 700), 284 (ꢀ 4500) nm; 1H NMR (500 MHz, CDCl3) and 13C
NMR (125 MHz, CDCl3) (see Table 3); HRESIMS m/z [M +
1]+ 517.2778 (calcd for C29H41O8, 517.2801).
P er acetylation of P seu dopter osin Z (11). Pseudopterosin
Z (3 mg, 0.006 mmol) was dissolved in a 1:1 mixture of acetic
anhydride-pyridine (1 mL) and stirred at 20 °C overnight.
Evaporation in vacuo of the volatile materials followed by silica
gel column chromatography of the oily residue isolated af-
seco-P seu d op ter osin H (12): white amorphous powder;
forded triacetate 16 (2.5 mg, 66%): colorless viscous oil; [R]20
[R]25 -142.3° (c 0.8, CHCl3); IR (film) νmax 3339, 2954, 2928,
D
D
2871, 1743, 1451, 1376, 1228, 1084 cm-1; UV (MeOH) λmax 208
(ꢀ 54 600), 228 (ꢀ 17 000), 280 (ꢀ 7900) nm; 1H NMR (500 MHz,
CDCl3) and 13C NMR (125 MHz, CDCl3) (see Table 3); HR-
FABMS m/z [M]+ 476.2771 (calcd for C27H40O7, 476.2774).
seco-P seu d op t er osin I (13): white amorphous powder;
-193.5° (c 1.0, CHCl3); 1H NMR (500 MHz, CDCl3) δ 6.50 (1H,
s, C-9 OH), 5.58 (1H, dd, J ) 10.3, 3.2 Hz, H-3′), 5.42 (1H, br
s, H-4′), 5.40 (1H, dd, J ) 10.2, 3.7 Hz, H-2′), 5.23 (1H, d, J )
3.6 Hz, H-1′), 5.10 (1H, d, J ) 8.8 Hz, H-14), 4.47 (1H, d, J )
13.0 Hz, H-5′ax), 3.75 (1H, dd, J ) 13.1, 2.5 Hz, H-5′eq), 3.57
(1H, br m, H-1), 3.34 (1H, m, H-7), 2.17 (3H, s), 2.14 (3H, s),
2.09 (3H, s, Me-20), 2.09 (3H, s), 2.02 (1H, m, H-4), 1.72 (3H,
br s, Me-17), 1.66 (3H, br s, Me-16), 1.64-1.50 (2H, m, H-2R,
H-3), 1.45 (1H, m, H-6â), 1.22 (3H, d, J ) 6.9 Hz, Me-19), 1.14
(1H, m, H-5R), 1.03 (3H, d, J ) 6.0 Hz, Me-18); LRESIMS m/z
(M + H)+ 559.
[R]25 -92.4° (c 2.1, CHCl3); IR (film) νmax 3472, 3363, 2957,
D
2927, 2851, 1746, 1498, 1448, 1376, 1232 cm-1; UV (MeOH)
1
λmax 208 (ꢀ 57 500), 228 (ꢀ 17 300), 278 (ꢀ 4200) nm; H NMR
(500 MHz, CDCl3) δ 7.06 (1H, br s, C-8 OH), 6.51 (1H, br s,
H-5), 5.30 (1H, dd, J ) 9.7, 3.4 Hz, H-2′), 5.15 (1H, d, J ) 3.5
Hz, H-1′), 4.39, (1H, dd, J ) 12.6, 1.6 Hz, H-5′ax), 4.27 (1H,
br d, J ) 9.5 Hz, H-3′), 4.18 (1H, br s, H-4′), 3.97 (1H, dd, J )
12.6, 2.5 Hz, H-5′eq), 3.14 (1H, m, H-1), 2.63 (1H, m, H-4),
2.29 (3H, s, Me-19), 2.25 (3H, s, COCH3), 2.04 (2H, m, H-13),
1.99 (1H, m, H-11), 1.80 (1H, m, H-2â), 1.71 (3H, br s, Me-16),
1.62 (3H, br s, Me-17), 1.49-1.16 (3H, m, H-12, H-2R), 1.17
(3H, d, J ) 6.9 Hz, Me-20), 0.71 (3H, d, J ) 6.9 Hz, Me-18);
13C NMR (125 MHz, CDCl3) δ 170.9 (s, COCH3), 146.0 (s, C-8),
141.6 (s, C-7), 137.1 (s, C-10), 131.2 (s, C-15), 128.9 (s, C-9),
127.3 (s, C-6), 124.8 (d, C-14), 121.6 (d, C-5), 101.5 (d, C-1′),
71.7 (d, C-2′), 68.9 (d, C-4′), 68.1 (d, C-3′), 63.5 (t, C-5′), 39.5
(d, C-4), 38.4 (d, C-11), 35.7 (t, C-12), 28.0 (t, C-2), 27.7 (d,
C-1), 26.2 (t, C-13), 25.8 (q, C-16), 21.0 (q, C-20), 20.9 (q,
COCH3), 18.5 (t, C-3), 17.7 (q, C-17), 17.2 (q, C-19), 16.4 (q,
C-18); HRFABMS m/z [M]+ 476.2797 (calcd for C27H40O7,
476.2774).
Ba sic Hyd r olysis of P seu d op ter osin s P -S (1-4). Indi-
vidual samples of approximately 5-6 mg of each pseudopterosin
were treated with 4 mL of 5% KOH/MeOH, and the resulting
suspension was stirred overnight at 20 °C. The solution was
diluted with H2O (5 mL), acidified to neutrality with 0.5 N
HCl, and extracted with CHCl3 (3 × 10 mL). The combined
organic layers were dried (MgSO4), filtered, and concentrated
1
in vacuo to yield each time pseudopterosin T (5). The H and
13C NMR data, TLC retention time, and optical rotation were
identical with those of the natural product.
Ba sic Hyd r olysis of P seu d op ter osin s U-X (6-9). An
artificially prepared mixture of pseudopterosins U-X (∼8 mg)
was treated with 4 mL of 5% KOH-MeOH, and after the
suspension was stirred overnight at 20 °C the solution was
poured onto H2O (8 mL), acidified to neutrality, and extracted
with CHCl3 (3 × 10 mL). The combined organic layers were
dried (MgSO4), filtered, and concentrated in vacuo to yield
pseudopterosin Y (10) as the sole product. The 1H and 13C NMR
data, TLC retention time, and optical rotation were identical
with those of the natural product.
P er a cetyla tion of P seu d op ter osin s P -T (1-5). Indi-
vidual samples of approximately 3-4 mg of each pseudopterosin
were dissolved in a 1:1 mixture of acetic anhydride-pyridine
(1 mL) and stirred at 20 °C overnight. Evaporation in vacuo
of the volatile materials followed by silica gel column chro-
matography of the oily residue isolated afforded each time the
same triacetate 14 (average yield ) 69%): colorless viscous
Aglycon Der iva tive fr om P seu d op ter osin
P (1). A
stirred mixture of pseudopterosin P (100 mg, 0.205 mmol),
benzyl bromide (100 µL, 0.72 mmol), and anhydrous K2CO3
(99 mg, 0.72 mmol) in dry acetone (15 mL) was refluxed under
N2 for 5 h and then allowed to cool to room temperature. After
solvent removal, the residue was taken up with water (30 mL)
and the aqueous layer was repeatedly extracted with CHCl3
(3 × 10 mL). The combined organic layer was dried (MgSO4),
filtered, and concentrated to afford a yellowish oily residue.
Without further purification, this residue was dissolved in
MeOH (15 mL) and treated with 1 N HCl (10 mL), and the
mixture was carefully warmed to 55 °C for 12 h. After allowing
oil; [R]20 -45.7° (c 0.7, CHCl3); 1H NMR (500 MHz, CDCl3) δ
D
6.85 (1H, s, C-9 OH), 5.59 (1H, dd, J ) 11.0, 3.1 Hz, H-3′),
5.43 (2H, m, H-2′, H-4′), 5.18 (1H, d, J ) 3.5 Hz, H-1′), 4.92
(1H, d, J ) 9.2 Hz, H-14), 4.69 (1H, q, J ) 6.6 Hz, H-5′), 3.66
(1H, dd, J ) 9.2, 8.8 Hz, H-1), 3.18 (1H, m, H-7), 2.20 (3H, s),
2.16 (3H, s), 2.09 (3H, s, Me-20), 2.02 (3H, s), 1.92 (1H, m,
H-2â), 1.71 (3H, br s, Me-17), 1.66 (3H, br s, Me-16), 1.32-
1.23 (2H, m, H-6â, H-3), 1.24 (3H, d, J ) 6.5 Hz, Me-6′), 1.23
(3H, d, J ) 6.8 Hz, Me-19), 1.02 (3H, d, J ) 6.0 Hz, Me-18),
0.90 (1H, m, H-5R); LRESIMS m/z (M + H)+ 573.