V. Costantino et al. / Bioorg. Med. Chem. 16 (2008) 2077–2085
2083
Four major fractions were obtained, composed of (i)
the known GSL 3 (25.9 mg), whose structure was
determined by comparison of its H NMR and mass
4.2.3. Compounds 2c–2d (inseparable mixture). Colorless
oil. ESIMS (positive ion mode, MeOH) m/z 1176, 1190,
1
1
and 1204 ([M+Na]+ series). H NMR of 2c (CDCl3): d
spectra with those reported,11, (ii) a mixture of com-
pounds 2a and 2b (5.4 mg), (iii) a mixture of com-
pounds 2c and 2d (6.8 mg), and (iv) partially
purified compound 1b (12.0 mg). Further normal-
phase HPLC purification of this last fraction [eluent:
n-hexane/i-PrOH (85:15)] gave 5.0 mg of pure corrugo-
side peracetate (1b).
6.48 (1H, d, J = 9.2 Hz, NH-2), 5.78 (1H, br.s, H-10),
5.74 (2H, s, H-4 and H-5), 5.54 (1H, m, H-3), 5.34
(1H, t, J = 9.8 Hz, H-30), 5.24 (1H, t, J = 9.8 Hz, H-
40), 5.23 (overlapped, H-200), 5.14 (1H, dd, J = 9.8 and
7.9 Hz, H-20), 4.74 (2H, br. s, H2-19), 4.69 (1H, m, H-
11), 4.54 (1H, m, H-2), 4.47 (1H, br. dd, J = 9.1 and
4.5 Hz, H-8), 4.22 (1H, dd, J = 12.5 and 4.0 Hz, H-
60a), 4.12 (1H, d, J = 7.9 Hz, H-10), 4.08 (1 H, dd,
J = 12.5 and 2.2 Hz, H-60b), 3.77 (1H, dd, J = 10.3
and 3.7 Hz, H-1a), 3.45 (1H, dd, J = 10.3 and 4.4 Hz,
H-1b), 3.21 (1H, ddd, J = 9.8, 4.0, and 2.2 Hz, H-50),
2.19 (1H, m, H-6a), 2.04 (1H, m, H-6b), 2.00 (3H, s,
Ac), 1.96 (1H, m, H-300), 1.83 (3H, s, Ac), 1.81 (3H, s,
Ac), 1.79 (3H, s, Ac), 1.66 (overlapped, H-7a), 1.67
(3H, s, Ac), 1.65 (3H, s, Ac), 1.60 (overlapped, H-12a),
1.45(overlapped, H-400), 1.44 (overlapped, H-7b), 1.41
(overlapped, H-12b), 1.32 (broad band, alkyl chain pro-
tons), 0.90 (6H, t, J = 7.0, terminal Me groups). 1H
NMR of 2d (CDCl3): same signals as for compound
2c, except for d 5.79 (1H, br.s, H-10), 4.82 (1H, br. d,
J = 15.8 Hz, H-19a), 4.60 (1H, br. d, J = 15.8 Hz, H-
19b), 4.52 (overlapped, H-11), 4.45 (1H, br. dd, J = 9.0
and 4.5 Hz, H-8), 1.76 (overlapped, H-12a), 1.48 (over-
lapped, H-12b). 13C NMR of 2c (CDCl3): d 170.6 (C,
C-100), 170.5-169.1 (several C, acetyl CO groups), 136.6
(C, C-9), 132.8 (CH, C-5), 127.1 (CH, C-4), 125.8
(CH, C-10), 100.7 (CH, C-10), 84.7 (CH, C-8), 78.2
(CH, C-11), 74.4 (CH, C-200), 73.0 (CH, C-30), 72.9
(CH, C-3), 72.3(CH, C-50), 71.7 (CH, C-20), 69.4
(CH2, C-19), 68.5 (CH, C-40), 67.2 (CH2, C-1), 61.6
(CH2, C-60), 51.8 (CH, C-2), 32.9 (CH2, C-12), 32.2
(CH2, C-300), 31.9 (CH2, x–2), 30.7 (CH2, C-7), 30.6–
29.5 (several CH2, alkyl chains), 28.7 (CH2, C-6), 25.6
(CH2, C-400), 23.1 (CH2, x–1), 20.7-20.1 (several CH3,
acetyl Me groups) , 14.3 (CH3, x). 13C NMR of 2d
(CDCl3): same signals as for compound 2c, except for
d 136.4 (C, C-9), 125.2 (CH, C-10), 84.5 (CH, C-8),
78.5 (CH, C-11), 69.5 (CH2, C-19), 33.5 (CH2, C-12).
4.2.1. Corrugoside peracetate (1b). Colorless oil. ESI-MS
(positive ion mode, MeOH) m/z 1738, 1752, and 1766
1
([M + Na]+ series) H and 13C NMR: Table 1; Compo-
sition in fatty acids: Table 2; Composition in sphinga-
nines: Table 3.
4.2.2. Compounds 2a–2b (inseparable mixture). Colorless
oil. HRESI-MS (positive ion mode, MeOH) m/z
1176.7036
([M+Na]+,
C61H103NNaO19
gives
1176.7022), 1190.7190 ([M+Na]+, C62H105NNaO19 gives
1190.7179), and 1204.7381 ([M+Na]+, C63H107NNaO19
gives 1204.7335). 1H NMR of 2a (CDCl3): d 6.50
(1H, d, J = 8.9 Hz, NH-2), 5.83 (1H, m, H-5), 5.76
(1H, br. s, H-10), 5.64 (1H, dd, J = 15.1 and 6.3 Hz,
H-4), 5.54 (1H, m, H-3), 5.35 (overlapped, H-200), 5.33
(1H, t, J = 9.8 Hz, H-30), 5.25 (1H, t, J = 9.8 Hz,
H-40), 5.15 (1H, dd, J = 9.8 and 7.9 Hz, H-20), 4.73
(1H, br. d, J = 15.8 Hz, H-19a), 4.68 (overlapped, H-
11), 4.67 (overlapped, H-19b), 4.58 (1H, m, H-2), 4.30
(1H, br. dd, J = 8.1 and 5.1 Hz, H-8), 4.23(1H, dd,
J = 12.5 and 4.0 Hz, H-60a), 4.11 (1H, d, J = 7.9 Hz,
H-10), 4.07(1H, dd, J = 12.5, 2.2 Hz, H-60b), 3.79 (1H,
dd, J = 10.3 and 3.3 Hz, H-1a), 3.48 (1H, dd, J = 10.3
and 4.2 Hz, H-1b), 3.19 (1H, ddd, J = 9.8, 4.0, and
2.2 Hz, H-50), 2.08 (2H, m, H2-6), 2.02 (overlapped,
H-300a), 1.97 (3H, s, Ac), 1.96 (overlapped, H-300b),
1.85 (3H, s, Ac), 1.81 (3H, s, Ac), 1.80 (3H, s, Ac),
1.71 (overlapped, H-7a), 1.68 (3H, s, Ac), 1.66 (3H, s,
Ac), 1.61 (overlapped, H-12a), 1.47 (overlapped,
H-7b), 1.47 (overlapped, H-400), 1.43 (overlapped,
H-12b), 1.32 (broad band, alkyl chain protons), 0.90
1
(6H, t, J = 7.0, terminal Me groups). H NMR of 2b
4.3. Deacetylation of compound 1b
(CDCl3): same signals as for compound 2a, except for
d 4.75 (1H, br. d, J = 15.8 Hz, H-19a), 4.60 (overlapped,
H-19b), 4.53 (1H, m, H-11), 4.27 (1H, br. dd, J = 8.1
and 5.1 Hz, H-8), 1.75 (overlapped, H-12a), 1.49 (over-
Compound 1b (3.0 mg) was dissolved in 950 ll of
MeOH, and 50 ll of a 0.4 M solution of MeONa in
MeOH was added. The reaction was allowed to proceed
for 18 h at 25 ꢁC, then the reaction mixture was dried
under nitrogen and the residue partitioned between
water and chloroform. After removal of the solvent,
the organic layer gave 2.1 mg of the native glycosphin-
golipid 1a.
lapped, H-12b). 13C NMR of 2a (CDCl3):
d
170.0-168.9 (several C, acetyl CO groups), 169.8 (C,
C-100), 136.2 (C, C-9), 135.0 (CH, C-5), 126.2 (CH,
C-4), 125.9 (CH, C-10), 100.8 (CH, C-10), 85.5 (CH,
C-8), 78.2 (CH, C-11), 74.3 (CH, C-200), 73.8 (CH,
C-3), 73.1 (CH, C-30), 72.3(CH, C-50), 71.7 (CH, C-20),
69.4 (CH2, C-19), 68.5 (CH, C-40), 67.3 (CH2, C-1),
61.3 (CH2, C-60), 51.3 (CH, C-2), 32.9 (CH2, C-12),
32.2 (CH2, C-300), 31.9 (CH2, x–2), 30.6–29.5 (sev-
eral CH2, alkyl chains), 30.4 (CH2, C-7), 28.9 (CH2,
C-6), 25.3 (CH2, C-400), 23.1 (CH2, x–1), 20.6–19.9
(several CH3, acetyl Me groups), 14.3 (CH3, x). 13C
NMR of 2b (CDCl3): same signals as for compound
2a, except for d 136.0 (C, C-9), 125.4 (CH, C-10), 85.3
(CH, C-8), 78.4 (CH, C-11), 69.5 (CH2, C-19), 33.3
(CH2, C-12).
25
D
4.3.1. Corrugoside (1a). Colorless amorphous solid, ½aꢁ
ꢀ5.7 (c = 0.5 in MeOH). ESIMS (positive ion mode,
MeOH) m/z 1192, 1206 and 1220 ([M+Na]+ series).
RESI-MS (positive ion mode, MeOH) m/z 1192.7918
([M + Na]+, C60H115NNaO2þ0 gives 1192.7910). 1H
NMR (pyridine-d5): d 8.59 (1H, d, J = 9.0 Hz, 2-NH),
7.64 (1H, d, J = 3.9 Hz, 2IV-OH), 6.95 (1H, d,
J = 3.7 Hz, 4000-OH), 6.92 (1H, br. s, 3000-OH), 6.65 (1H,
br. s, 3-OH), 6.62 (1H, br. s, 60-OH), 6.60 (1H, br. s,
600-OH), 6.52 (2H, br. s, 40-OH and 400-OH), 6.19 (1H,