+
◦
18
◦
1
J = 6.5 Hz), 1.81 (s, 3H), 1.73 (s, 3H); m/z (EI) 270 (4%, M ),
129–131 C (lit., 129–132 C); H NMR (CDCl
8.19 (d, 1H, J = 9.8 Hz), 7.62 (d, 1H, J = 2.4 Hz), 7.16 (s, 1H),
.01 (d, 1H, J = 2.4 Hz), 6.29 (d, 1H, J = 9.8 Hz), 4.56 (dd, 1H,
J = 3.1, 9.8 Hz), 4.46 (dd, 1H, J = 7.7, 9.8 Hz), 3.93 (t, 1H, J =
.7 Hz), 2.97 (bd, 1H, J = 3.7 Hz), 2.26 (s, 1H), 1.38 (s, 3H), 1.34
s, 3H). Following D O exchange, the peaks at 2.97 and 2.26 ppm
3
, 250 MHz): d
2
02 (100%).
7
4
-[5-(3,3-Dimethyloxiranyl)-3-methylpent-2-enyloxy]-furo[3,2-
g]chromen-7-one [2]. 3-Chloroperoxybenzoic acid (180 mg,
.04 mmol) was added to a stirred solution of bergamottin [1]
250 mg, 0.74 mmol) in DCM (10 mL). The solution was stirred at
10 C for 2 hours 30 minutes. The organic layer was washed with
aqueous sodium sulfite (10% w/v) and sodium carbonate (5%
w/v) (20 mL, 1 : 1), was dried and the solvent was evaporated
under reduced pressure. The title compound was obtained by
column chromatography, eluting with ethyl acetate–hexane (4 :
3
(
1
2
(
−
disappeared and the bt at 3.97 ppm became a dd at 3.93 ppm (J =
◦
+
3
.1 Hz, 7.6 Hz); m/z (EI) 304 (20%, M ).
4
-(6-Hydroxy-7-methoxy-3,7-dimethyloct-2-enyloxy)-furo[3,2-
ꢀ
ꢀ
g]chromen-7-one (6 -OH-7 -OMeB) [12]. (1R)-(−)-10-Camphor-
sulfonic acid (66 mg, 0.28 mmol) was added to a stirred solution
of 2 (100 mg, 0.28 mmol) in methanol (5 mL) under argon. On
completion of the reaction (TLC) a few drops of saturated aqueous
sodium bicarbonate solution were added and the methanol was
evaporated under reduced pressure. The residual oil was dissolved
in DCM (20 mL), then the organic layer washed with water (2 ×
1
). Removal of the solvent under reduced pressure furnished
a translucent oil, which crystallised on trituration and cooling
with hexane. Recovery by filtration afforded colourless crystals
◦
17
◦
1
(
212 mg, 0.60 mmol, 81%). Mp 69–70 C (lit., 67–70 C); H
NMR (CDCl
3
, 250 MHz): d 8.17 (d, 1H, J = 9.8 Hz), 7.61 (d, 1H,
J = 2.3 Hz), 7.17 (s, 1H), 6.96 (d, 1H, J = 2.3 Hz), 6.28 (d, 1H, J =
2
0 mL) and dried (MgSO ). Removal of the solvent yielded a
4
9
2
1
.8 Hz), 5.61 (t, 1H, J = 6.4 Hz), 4.97 (d, 2H, J = 6.4 Hz), 2.73–
translucent oil, which upon trituration with ether–hexane (1 : 1)
furnished colourless crystals (89 mg, 0.23 mmol, 82%). Mp 67–
8 C; mmax cm 3581, 1731, 1622; H NMR (CDCl , 250 MHz):
.71 (m, 1H), 2.26–2.22 (m, 2H), 1.71 (s, 3H), 1.70–1.61 (m, 2H),
+
◦
.32 (s, 3H), 1.28 (s, 3H); m/z (EI) 354 (23%, M ), 202 (100%).
−1
1
6
3
d 8.17 (d, 1H, J = 9.8 Hz), 7.60 (d, 1H, J = 2.3 Hz), 7.18 (s, 1H),
4
-(3,3-Dimethyloxiranylmethoxy)-furo[3,2- g]chromen-7-one
6
.98 (d, 1H, J = 2.3 Hz), 6.27 (d, 1H, J = 9.8 Hz), 5.59 (t, 1H, J =
.7 Hz), 4.94 (d, 2H, J = 6.7 Hz), 3.36 (bd, 1H, J = 9.8 Hz), 3.24 (s,
[
10]. 3-Chloroperoxybenzoic acid (160 mg, 0.93 mmol) was
added to a stirred solution of 9 (250 mg, 0.92 mmol) in
dichloromethane (10 mL) at −10 C in an ice–methanol bath.
6
◦
3H), 2.50 (bs, 1H), 2.45–2.33 (m, 1H), 2.20–2.08 (m, 1H), 1.71 (s,
3
H), 1.56–1.41 (m, 2H), 1.10 (s, 6H). Following D
2
O exchange the
After 2 hours 30 minutes the temperature was allowed to rise to
room temperature and the reaction was stirred for a further hour.
The solution was washed with aqueous sodium sulfite (10% w/v)
and sodium carbonate (5% w/v) (20 mL, 1:1). Evaporation of
the organic layer under reduced pressure yielded yellow crystals,
which were purified by column chromatography eluting with ethyl
acetate–hexane (3 : 7). The relevant fractions were combined and
removal of the solvent under reduced pressure afforded pale yellow
bs at 2.50 ppm disappeared and the bd at 3.36 ppm became a dd
1
3
at 3.36 ppm (J = 2.0 Hz, 10.2 Hz); C NMR (CDCl
3
, 63 MHz): d
59.7, 156.4, 151.0, 147.2, 143.3, 141.5, 138.0, 117.4, 112.6, 110.9,
05.9, 103.4, 92.6, 75.7, 74.6, 68.0, 35.0, 27.5, 19.0, 17.0, 15.1;
1
1
+
m/z (EI) 386 (5%, M ), 202 (74%); found (EI) 386.1736; C22
H
26
O
6
requires 386.1729; found C 68.40%, H 6.83%; C22
C 68.38%, H 6.78%.
H
26
6
O requires
◦
16
crystals (228 mg, 0.80 mmol, 86%). Mp 141–142 C (lit., 142–
43 C); H NMR (CDCl
4
-Hydroxy-2,3-dihydrofuro[3,2-g]chromen-7-one (5-DHOH)
◦
1
1
7
6
1
1
3
, 250 MHz): d 8.23 (d, 1H, J = 9.8 Hz),
[
(
(
14]. Bergaptol [8] (350 mg, 1.73 mmol) was dissolved in acetone
120 mL) at 40 C under argon. Pd/C (10%, 700 mg), formic acid
.64 (d, 1H, J = 2.3 Hz), 7.23 (s, 1H), 6.97 (d, 1H, J = 2.3 Hz),
.36 (d, 1H, J = 9.8 Hz), 4.63 (dd, 1H, J = 4.4, 10.8 Hz), 4.46 (dd,
H, J = 6.5, 10.8 Hz), 3.26 (dd, 1H, J = 4.4, 6.5 Hz), 1.43 (s, 3H),
◦
653 lL, 17.3 mmol) and triethylamine (2.90 mL, 20.8 mmol) were
1
added to the solution. After 10 minutes H NMR indicated that
the reaction was complete. The solution was filtered through celite
and the solvent was removed under reduced pressure, affording
a light green oil, which solidified on cooling. The solid was
dissolved in acetone and pre-absorbed onto silica. Purification
by column chromatography furnished the desired compound after
elution with ethyl acetate–hexane (3 : 7) increasing to ethyl acetate
+
.35 (s, 3H); m/z (CI) 287 (100%, [M + H] ).
4
-(6,7-Dihydroxy-3,7-dimethylocta-2-enyloxy)-furo[3,2-g]-
ꢀ
ꢀ
chromen-7-one (6 ,7 -DHB) [3]. An aqueous solution of perchlo-
ric acid (9 mL, 3% v/v) was added dropwise to a stirred solution
of 2 (140 mg, 0.40 mmol) in 1,4-dioxane (15 mL) under argon at
room temperature. After 1 hour water (10 mL) was added and
the solution was extracted with ethyl acetate (3 × 15 mL). The
combined organic layers were washed with water (30 mL) and
(100%). The relevant fractions were combined and the solvent
was removed under reduced pressure, yielding an off-white solid
◦
−1
(
280 mg, 1.37 mmol, 79%). Mp 200–202 C; mmax cm 3303, 1669,
dried (MgSO
4
). Removal of the solvent under reduced pressure
1
3
1623; H NMR (d -acetone, 250 MHz): d 7.92 (d, 1H, J = 9.7 Hz),
yielded the desired compound as small colourless needles (100 mg,
.27 mmol, 68%). Mp 112–113 C (lit., 104–107 C); H NMR
CDCl
6
◦
17
◦
1
6
3
1
.13 (s, 1H), 5.92 (d, 1H, J = 9.7 Hz), 4.54 (t, 2H, J = 8.6 Hz),
13
6
0
(
2
9
(
.10 (t, 2H, J = 8.6 Hz); C NMR (d
-DMSO, 63 MHz): d 164.5,
3
, 250 MHz): d 8.16 (d, 1H, J = 9.8 Hz), 7.60 (d, 1H, J =
60.8, 156.3, 150.6, 139.8, 108.9, 108.8, 103.4, 89.7, 72.7, 26.5;
.4 Hz), 7.16 (s, 1H), 6.96 (d, 1H, J = 2.4 Hz), 6.28 (d, 1H, J =
.8 Hz), 5.60 (t, 1H, J = 6.7 Hz), 4.96 (d, 2H, J = 6.7 Hz), 3.33
+
m/z (EI) 204 (100%, M ); found (EI) 204.0421; C11
04.0423; found C 64.81%, H 3.91%; C11 requires C 64.71%,
H 3.95%.
H
8
O
4
requires
2
H
8
O
4
d, 1H, J = 10.4 Hz), 2.38–2.16 (m, 3H), 1.93 (bs, 1H), 1.67 (s,
3
(
H), 1.66–1.42 (m, 2H), 1.33 (s, 3H), 1.26 (s, 3H); m/z (EI) 372
+
6%, M ), 202 (100%).
-(2,3-Dihydroxy-3-methylbutoxy)-furo[3,2-g]chromen-7-one
oxypeucedanin hydrate) [11]. This compound was prepared as
4
-(3,7-Dimethylocta-2,6-dienyloxy)-2,3-dihydrofuro[3,2-g]-
4
chromen-7-one (5-DHB) [13]. Preparation as outlined for com-
◦
−1
(
pound 1. (115 mg, 0.33 mmol, 69%). Mp 61–62 C; mmax cm 1713,
1
outlined in the previous procedure. (78 mg, 0.26 mmol, 92%). Mp
1620; H NMR (CDCl
3
, 250 MHz): d 7.58 (d, 1H, J = 9.7 Hz),
This journal is © The Royal Society of Chemistry 2006
Org. Biomol. Chem., 2006, 4, 1604–1610 | 1609