J. CHEM. RESEARCH (S), 1997 423
H
•
OsCH2sO), 4.80 (d,
J 6.3 Hz, 1 H, axial proton of
•
HO
O
HO
O
HO
•
•
OsCH2sO), 4.70 (s, 2 H, CH2OH), 4.10 (dd, J1 10 Hz, J2:4 Hz,
1 H, equatorial proton of sCH2sO), 4.02 (d, J 10 Hz, 1 H,
benzylic methine), 3.88 (s, 3 H, OCH3), 3.40 (superimposed dd,
J1 = J2:10 Hz, 1 H, axial proton of CH2O), 2.65 (s, 1 H, OH), 2.08
(m, 1 H, methine H), 0.60 (d, J 7 Hz, 3 H, CH3); dC (125 MHz)
146.9, 143.9, 131.2, 126.2, 120.1, 109.3 (aromatic carbons), 94.3,
86.3, 73.2, 61.9, 56.3, 36.5 and 12.8; m/z 254 (Mǹ) (Found: C, 61.46;
H, 7.48. C13H18O5 requires C, 61.41; H, 7.08%).
MeO
MeO
MeO
NaOH
HCHO
base
–
6
1
2
HCHO
7
-Methoxy-10
-(5-methoxy-1,3-dioxan-4-yl)spiro[oxirane-2,9
-
endo-tricyclo[5.2.2.02,6]undeca-4
,10
-dien]-8
-one 4.sTo a solu-
tion of compound 3 (2 g, 7.87 mmol) in acetonitrile (30 ml) was
added freshly cracked cyclopentadiene (8 ml, excess) and the reac-
tion mixture was cooled in an ice bath (#0 °C). A solution of
NaIO4 (6 g, 28.1 mmol) in water (50 ml) was then added dropwise
to the reaction mixture with stirring. After stirring for 8 h, the
reaction mixture was filtered and extracted with diethyl ether
(3Å25 ml). The organic layer was washed with brine (10 ml) and
dried over anhydrous sodium sulfate. Removal of solvent followed
by chromatography [light petroleum–ethyl acetate (85:15)] of the
residue on silica gel furnished spiro compound 4 (1.8 g, 72%) as a
solid, which was recrystallised from light petroleum–ethyl acetate
(80:20), mp 132 °C. vmax/cmꢀ1 (KBr) 3063, 2939, 2849, 1743; dH (500
MHz) 5.93 (br s, 1 H, b-proton of b,g-enone), 5.77 (m, 1 H, olefinic
H), 5.6 (m, 1 H, olefinic H), 5.02 (d, J 6 Hz, 1 H, equatorial proton
–
HO
O
HO
O
HO
MeO
MeO
MeO
OR
–
O
– O
5
8
7
HCHO
HCHO
O
OH
HO
MeO
O–
O
O
of OsCH2sO), 4.64 (d,
J 6 Hz, 1 H, axial proton of
MeO
OsCH2sO), 4.06 (dd, J1 11 Hz, J2:4 Hz, 1 H, equatorial proton
of OCH2), 3.72 (d, J 10 Hz, 1 H, methine H), 3.6 (s, 3 H, OCH3), 3.5
(br d, J:6 Hz, 1 H, methine H), 3.28 (superimposed dd,
J1 = J2 = 11 Hz, 1 H, axial proton of OCH2sC), 3.06 (d, over-
lapped with other signal, total 2 H, methine and 1 H, OCH2 of
oxirane), 2.88 (d, 1 H, J:6.5 Hz, OsCH2 of oxirane group), 2.72
(s, 1 H, methine H at the bridgehead), 2.69 (m, 1 H, allylic methyl-
ene of cyclopentene ring), 2.05 (d, J 18 Hz, 1 H, allylic methylene),
1.95 (m, 1 H, methine H) and 0.67 (d, J 3.5 Hz, 3 H, CH3); dC (125
MHz) 204.9 (CO), 141.2, 135.0, 128.3, 127.4 (olefinic carbons),
93.7, 88.2, 84.2, 72.5, 59.0, 53.9, 53.7, 53.0, 44.1, 38.8, 36.7, 32.4 and
12.8; m/z 318 (Mǹ) (Found: C, 68.37; H, 7.15. C18H22O5 requires C,
67.91; H, 6.97%).
hydroxymethylation
OH
H
10
O
9
H
O
HO
MeO
O
H
3
Scheme 2
OH
OH
OH
5-Allyl-2-hydroxy-3-methoxybenzyl Alcohol (12).sTo a solution
of eugenol 11 (1 g, 6.1 mmol) in water (5 ml) and formalin
(37–41%; 3 ml) was added NaOH (0.2 g) with stirring at room
temperature. After stirring for 5 h, the reaction mixture was acid-
ified with HCl (50%) and extracted with diethyl ether (3Å20 ml).
The ether layer was washed with brine (10 ml) and dried over
anhydrous sodium sulfate. The solvent was removed under reduced
pressure and the residue was chromatographed on silica gel. Elu-
tion with light petroleum–ethyl acetate (70:30) furnished the alco-
hol 12 (0.98 g, 83%) as a liquid; vmax/cmꢀ1 (KBr) 3400, 1640, 1615;
dH 1H NMR (300 MHz) 6.66 (m, 2 H, aromatic protons), 6.03 (br s,
1 H, ArOH), 5.94 (m, 1 H, olefinic H), 5.07 (m, 2 H, olefinic H),
4.66 (br s, 2 H, ArCH2), 3.87 (s, 3 H, OCH3), 3.30 (d, J:7 Hz, 2 H,
ArsCH2sOs), 2.44 (s, 1 H, ArsCH2sOH); m/z 194 (Mǹ).
MeO
MeO
HCHO
base
11
12
Scheme 3
double bond and also described the transformation of the
Prins-type product into a tricyclic system having a b,g-enone
chromophore of synthetic utility.
Experimental
We thank R.S.I.C., I.I.T. Bombay, and T.I.F.R., Bombay,
for spectral facilities. P. S. is thankful to CSIR New Delhi for
a senior fellowship. Financial support to V. S. from DST New
Delhi is gratefully acknowledged.
IR spectra were recorded on a Nicolet Impact 400 FT-IR instru-
ment. Mass spectra were recorded on a Hewlett Packard GCD
1800-A instrument. 1H NMR (300 MHz) and 13C NMR (75 MHz)
spectra were recorded on a Varian VXR 300S instrument. Some
13C NMR (125 MHz) spectra were also taken on a GE NMR
Omega instrument. All the samples were dilute solutions in CDCl3
with SiMe4 as internal standard. Melting points were taken on a
Buchi-type apparatus and are uncorrected. All the organic extracts
were dried over anhydrous Na2SO4. Reactions were monitored
with TLC and spots visualized with iodine vapour. Chromato-
graphic separations were performed on silica gel–light petrol-
eum.
Received, 19th May 1997; Accepted, 31st July 1997
Paper E/7/03410E
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1 H, OH), 5.16 (d,
J 6.30 Hz, 1 H, equatorial proton of