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3, 3.36 g (24.0 mmol, 6.0 equiv.) of 3,5-dihydroxybenzyl
alcohol and 6.62 g (48.0 mmol, 12 equiv.) of K2CO3 in
300 ml of pyridine. After this time, 3.80 g (48.0 mmol, 12
equiv.) of CuO nano-powder was added, and the mixture
was heated to a vigorous reflux by sand bath (a normal
reflux was not sufficient to bring about reaction) for 3
weeks. After the solvent was removed by reduced pressure,
the crude material was dried on a high vacuum line for 1 h
(excessive drying and/or exposing the mixture to air for
extended periods led to greatly reduced yields). Sub-
sequently, 250 ml of THF was added, and the reaction
mixture was sonicated for 30 min. The mixture was then
filtered through THF-wet Celite, and the solvent of the
filtrate was evaporated under reduced pressure to give a
brown crude solid. This material was dried at RTovernight
under high vacuum. To the dried solid 50 ml of CHCl3 was
added, and the suspension was sonicated for 20 min. The
solid obtained after filtration (the filtrate should be green)
was suspended once again in CHCl3, sonicated for 20 min
and dried under vacuum for overnight at 1208C to give
,3.9 g crude octol 4 as an off-white powder (yield by
weight: 65%, ca. 75% purity by NMR, therefore, 45%
estimated yield).
under high vacuum (at 1208C) afforded pure octol 4
(690 mg, yield: 92%).
Crude octa-acid 1
To a solution of 3.5 g (2.16 mmol, 1.0 equiv.) of crude
octol 4 in 300 ml degassed DMA and 300 ml of t-BuOH
9.57 g (60.55 mmol, 28.0 equiv.) of KMnO4 was added.
The resulting purple solution was stirred at RT for 2 days.
The reaction mixture was filtered, and the solid was
washed thoroughly with 4 £ 200 ml distilled water. The
combined filtrate was evaporated under high vacuum and
dried at RT for 16 h. A total of 20 ml of 20% HCl was then
added to the solid, and the suspension was sonicated for
5 min. Following filtration, the solid was shaken with
150 ml of distilled water. Filtration and washing with
water gave crude octa-acid 1, which was dried at 1208C for
overnight (,3.4 g).
Octa-ester 5 (hepta-esters 6 and 7)
HCl gas was bubbled through a solution of 2.5 g of crude
octa-acid 1 in 150 ml of ethanol for ,2 min. To this
suspension 100 ml of CHCl3 was added, and the solution
was heated up to reflux for 4 days. The solvent was then
removed, and 10 ml of ethanol was added to the residue,
the resulting suspension was shaken and then filtered. The
resulting off-white solid was dried at 1208C for 16 h.
Chromatography of the crude product afforded three main
products: octa-ester 5 (1.26 g), hepta-ester-rim-OH 6
(0.38 g) and hepta-ester-feet-OH 7 (0.17 g). Octa-ester 5:
Octa-acetate of octol 4
To 10 ml of Ac2O 1 g (0.62 mmol) of crude octol 4 was
added. The mixture was heated to 1008C (oil bath) for 16 h.
The homogeneous solution was then cooled to RT, and the
solvent was removed under high vacuum. The residue was
dried for 2 h and purified by chromatography (0.91 g,
yield: 75%). Rf ¼ 0.25 (CHCl3/Acetone, 15:1, v/v). Mp
1
Rf ¼ 0.33 (CHCl3/Acetone, 40:1, v/v). Mp .2508C. H
NMR (500 MHz, CDCl3) d 7.88 (d, J ¼ 2.2, 8H), 7.19 (s,
4H), 7.02 (t, J ¼ 2.1, 4H), 6.78 (t, J ¼ 2.2, 4H), 6.52–6.50
(m, 8H), 5.97 (s, 4H), 4.79 (t, J ¼ 8.3, 4H), 4.52 (s, 4H),
4.43 (q, J ¼ 7.1, 8H), 4.14 (q, J ¼ 7.1, 8H), 2.58 (q,
J ¼ 7.7, 8H), 2.31 (t, J ¼ 7.4, 8H), 1.44 (t, J ¼ 7.1, 12H),
1.26 (t, J ¼ 7.1, 12H). MS (MALDI): Calcd. 2061
[M þ Ag]þ, Found: 2061 [M þ Ag]þ. Anal. Calcd. for
1
.2508C. H NMR (500 MHz, CDCl3) d 7.20 (d, J ¼ 2.0,
8H), 7.14 (s, 4H), 6.98 (t, J ¼ 2.2, 4H), 6.54 (t, J ¼ 2.0,
4H), 6.51 (d, J ¼ 2.2, 8H), 6.01 (s, 4H), 5.20 (s, 8H), 4.82
(t, J ¼ 8.2, 4H), 4.53 (s, 4H), 4.16 (t, J ¼ 6.5, 8H), 2.32 (q,
J ¼ 8.0, 8H), 2.12 (s, 12H), 2.07, (s, 12H), 1.71–1.65 (m,
8H). MS (MALDI): Calcd. 2061 [M þ Ag]þ, Found: 2061
[M þ Ag]þ. Anal. Calcd. for C112H96O32: C, 68.85; H,
4.95 Found: C, 68.18; H, 4.94.
C112H96O32: C, 68.85; H, 4.95 Found: C, 69.09; H, 4.90.
Hepta-ester-rim-OH 6: Rf ¼ 0.37 (CHCl3/Acetone, 15:1,
1
v/v). Mp .2508C. H NMR (500 MHz, CDCl3) d 7.89–
7.87 (m, 6H), 7.23 (d, J ¼ 1.9, 2H), 7.19 (s, 4H), 7.01 (m,
4H), 6.78 (m, 3H), 6.54 (m, 1H), 6.51 (m, 8H), 6.01 (s,
1H), 5.98 (d, J ¼ 2.4, 3H), 4.84 (s, 2H), 4.80 (m, 4H), 4.53
(s, 4H), 4.43 (q, J ¼ 7.1, 6H), 4.15 (qd, J ¼ 7.1, 1.1, 8H),
2.59 (q, J ¼ 7.5, 8H), 2.32 (t, J ¼ 7.0, 8H), 1.44 (t,
J ¼ 7.1, 9H), 1.26 (td, J ¼ 7.1, 1.2, 12H). MS (MALDI):
Calcd. 2019 [M þ Ag]þ, Found: 2019 [M þ Ag]þ. Anal.
Calcd. for C110H94O31: C, 69.10; H, 4.96 Found: C, 68.21;
H, 5.05. Hepta-ester-feet-OH 7: Rf ¼ 0.24 (CHCl3/
Pure octol 4
To 910 mg (0.46 mmol, 1 equiv.) of octa-acetate 5 in 60 ml
DMA 10 ml of H2O and 625 mg (14.9 mmol, 32 equiv.) of
LiOH·H2O were added. The solution was heated to 508C
for 24 h. The solvent was removed under high vacuum, and
the residue was dried at RT for 16 h. A total of 30 ml of 1 M
HCl and 120 ml of H2O were added to the resulting solid,
and the mixture was sonicated for 30 min. Filtration and
washing with solid with distilled water gave octol 4, which
was dried at RT for 16 h. Acetone (10 ml) was then added
to this solid, and the mixture was sonicated for 2 min and
allowed to stand for 2 h. Filtration and drying of the solid
1
Acetone, 15:1, v/v). Mp .2508C. H NMR (500 MHz,
CDCl3) d 7.90–7.86 (m, 8H), 7.24 (s, 2H), 7.17 (s, 2H),
7.02 (m, 4H), 6.78 (m, 4H), 6.54–6.50 (m, 8H), 5.97 (s,
4H), 4.82–4.74 (m, 4H), 4.54 (s, 1H), 4.52 (s, 3H), 4.43