48
X. Liu et al.
and the filtrate was concentrated to about 10 ml, then it was separated by
column chromatography (chloroform-methanol, 100:1) and 3a (0.66 g,
20
87%) was obtained as a pale yellow gum. [α]
= +8.4◦ (c 1.0, CHCl3);
D
1H-NMR(CDCl3,) δ 8.01 (s, 1H), 7.78 (s, 1H), 7.71 (s, 1H), 7.47–7.26 (m,
10H), 5.55 (s, 2H), 4.98–4.97 (q, 1H), 4.61 (s, 2H), 4.29–4.23 (m, 2H),
13
3.29–3.25 (q, 1H), 3.09–3.06 (d, 1H), 2.40 (s, 3H);
C-NMR(CDCl3) δ
200.1, 160.8, 156.5, 152.3, 151.9, 142.3, 141.2, 137.5, 135.7, 128.4, 128.4,
128.1, 128.1, 127.9, 127.7, 117.9, 73.4, 68.7, 63.8, 57.5, 33.8, 24.9; FT-ICRMS
m/z M+H+, 484.1983. Calc. for C27H26N5O4.
1S-1-[2-oxo-3-en-3-[(Phenylmethoxy)methyl]cyclopentyl]-2,4(1H, 3H)-
pyrimidinedion (3b). [1 S-(1α, 2β, 3α, 4β)]-1-[2-Hydroxy-4-(pheny-
methoxy)-3-[(phenylmethoxy)methyl] cyclopentyl]-2,4(1H,3H)-pyrimid-
inedion (1b)[3,4] was treated with Dess-Martin reagent and silica gel
successfully as 1a was treated, 3b was obtained in 73% yield as amorphous
20
1
solid; [α]
= +5.8◦ (c 1.0, CHCl3); H-NMR(CDCl3,) δ 8.37 (br, 1H),
D
7.62 (s, 1H), 7.37–7.29 (m, 5H), 6.97–6.96 (d, 1H), 5.74–5.73 (q, 1H),
4.61–4.59 (t, 3H), 4.26–4.25 (m, 2H), 3.18–3.13 (m, 1H), 2.84–2.79 (m,
1H); FAB-MS m/z calcd for M+H+ 313.3, found 313.0.
[1S-(1α, 2β, 3α, β)]-N-Acetyl-6-(phenylmethoxy)-9-[2-acetoxy-4-(4-
methoxybenzyloxy)-3-[(phenylmethoxy)methyl]cyclopentyl]-9H-purin-
2-amine (5). To a stirred solution of [1S-(1α, 2β, 3α, 5β)]-5-[2-amino-6-
(phenylmethoxy)-9H-purin-yl]-3-(4-methoxybenzyloxy)-2-[(phenylmetho-
xy)methyl]cyclopentanol (4) (1 g, 1.72 mmol) in pyridine (20 ml), DMAP
(0.05 g) and acetyl chloride (0.5 ml, 6.88 mmol) were added, then the
mixture was stirred for 2 hours at rt and stood overnight. Pyridine was
evaporated in vacuo. The residue was dissolved in chloroform (200 ml) and
washed successively with saturated aqueous sodium bicarbonate solution
(100 ml) and brine (250 ml). After dried with magnesium sulfate and
evaporated, 5 (1.12 g, 96%) was obtained as a white amorphous solid.
[1S-(1α, 2β, 3α, 4β)]-4-[(2-Acetylamido)-6-(phenylmethoxy)-9H-purin-
yl]-3-acetoxy-2-[(phenylmethoxy)methyl]cyclopentanol (6). To a stirred so-
lution of 5 (1.1 g, 1.65 mmol) in dichloromethane-H2O (19:1, 40 ml),
DDQ (0.56 g, 2.48 mmol) was added. The mixture was stirred vigorously
for 14 hours, then was diluted with CH2Cl2 (100 ml) and washed with
saturated aqueous sodium bicarbonate solution (100 ml). The aqueous
solution was extracted with CH2Cl2 (100 ml), the combined organic phase
was dried by magnesium sulfate. After evaporated, a dark oily residue was
produced, which was purified by column chromatography (chloroform-
methanol, 20:1) and 6 (0.72 g, 80%) was obtained as a yellow amorphous
solid. 1H-NMR(CDCl3)δ 7.83 (br, 1H), 7.77 (s, 1H), 7.48–7.26(m, 10H), 5.58
(s, 2H), 5.56–5.54 (t, 1H), 5.04–5.00 (q, 1H), 4.56 (s, 2H), 4.52–4.50 (q,
1H), 3.77–3.75 (q, 1H), 3.68–3.65 (t, 1H), 2.70–2.65 (m, 1H), 2.54 (s, 3H),
2.34–2.27 (m, 2H), 1.95 (s, 3H). FAB-MS m/z M+H+, 546.2. C29H31N5O6
requires M+H+, 546.6.