Notes
Syn th eses of â-Tr ik eton es. Sodium methoxide was pre-
J ournal of Natural Products, 1999, Vol. 62, No. 3 489
70 eV 280 [M]+ (92), 265 (20), 237 (52), 224 (30), 210 (100)
196 (14), 167 (20), 154 (30), 149 (29), 139 (20), 126 (21), 113
(28), 99 (39), 96 (85), 81 (32), 70 (53), 55 (46); 1H NMR δ 18.37
(OH, s, 2′-OH), 2.98 (t, J ) 7 Hz, H-2), 1.66 [2H, br m (27 Hz),
H-3], 1.45 (6H, s, 3′-CH3) 1.37 (6H, s, 5′-CH3), 1.35 [4H, m
(hidden15), H - 4 + 5] 0.90 (3H, t, J ) 7 Hz, H-6); 13C NMR in
Table 1; GC (DB-1 column) Kovats Retention Index )1778 was
measured as described previously.3
pared by dissolving 0.3 g sodium in 5 mL MeOH. MeI (3 mL)
was added to the NaOMe solution followed by the addition of
mono-acyl phloroglucinol (1.5-2.5 mM) under N2. The reaction
mixture was heated under reflux for 3 h. The solvent was
evaporated under vacuum and the extract acidified with 1M
HCl (50 mL) and extracted with Et2O (3 × 50 mL). The ether
phase was then extracted with 5% Na2CO3 (200 mL). The
Na2CO3 extract was acidified with concentrated HCl, extracted
with Et2O (2 × 200 mL) and dried over anhydrous MgSO4 to
yield the triketone (yields between 70 and 85%). Final puri-
fication was achieved by high-vacuum bulb-to-bulb distillation
(1 mmHg, 150 °C). Spectral data for flavesone5 [2, 5-hydroxy-
4-(2-methyl-1-oxobutyl)-2,2,6,6- tetramethyl-4-cyclohexene-1,3-
dione, RN 22595-45-5], leptospermone5 [4, 5-hydroxy-4-(3-
methyl-1-oxobutyl)-2,2,6,6-tetramethyl-4-cyclohexene-1,3-
dione, RN 567-75-9], and grandiflorone6 [5, 5-hydroxy-4-(1-oxo-
3-phenylpropyl)-2,2,6,6-tetramethyl-4-cyclohexene-1,3-dione,
RN 50861-53-5 or 10499-26-0] matched the reported literature
values.
Ack n ow led gm en t. We thank M. Thomas and W. Red-
mond for assistance with NMR experiments; Tairawhiti
Pharmaceuticals for a sample of L. scoparium oil; J . Clarkson
for the C. dallachiana leaf collection; B. Clark for MS analyses;
B. McAllister for microanalyses; and N. Porter for a draft copy
of his manuscript. This research was supported in part by the
New Zealand Foundation for Research, Science and Technol-
ogy.
Refer en ces a n d Notes
(1) Ghisalberti, E. L. Phytochemistry 1996, 41, 7-22.
(2) Hellyer, R. O. Aust. J . Chem. 1968, 21, 2825-2828.
(3) Perry, N. B.; Brennan, N. J .; van Klink, J . W.; Harris, W.; Douglas,
M. H.; McGimpsey, J . A.; Smallfield, B. M.; Anderson, R. E. Phy-
tochemistry 1997, 44, 1485-1494.
(4) Porter, N. G.; Wilkins, A. L. Phytochemistry 1998, 50, 407-415.
(5) Bick, I. R. C.; Blackman, A. J .; Hellyer, R. O.; Horn, D. H. S. J . Chem.
Soc. 1965, 3690-3692.
(6) Hellyer, R. O.; Pinhey, J . T. J . Chem. Soc. (C) 1966, 1496-1498.
(7) Ashhurst, P. R. Chem. Ind. (London) 1966, 381.
(8) Boland, D. J .; Brophy, J . J .; House, A. P. N., Eds. Eucalyptus Leaf
Oils. Use, Chemistry, Distillation and Marketing. Inkata: Melbourne,
1991.
(9) Boland, D. J .; Brophy, J . J . “Essential oils of the eucalypts and related
genera. Search for chemical trends.” In ACS Symposium Series 525.
Bioactive Volatile Compounds from Plants; (Teranishi, R., Buttery,
R. G., Sugisawa, H., Eds., ACS: Washington, DC, 1993; Chapter 7,
pp 72-87.
(10) Brophy, J . J .; Goldsack, R. J .; Forster, P. I.; Clarkson, J . R.; Fookes,
C. J . R. J . Essent. Oil Res. 1996, 8, 465-470.
(11) Hill, K. D.; J ohnson L. A. S. Telopea 1995, 6, 185-504.
(12) Sowmithran, D.; Prasad, K. J . R. Synthesis 1985, 545-546.
(13) Ayras, P.; Lotjonenen, S.; Widen, C. J . Planta Med. 1981, 42, 187-
194.
Isoleptospermone [3, 5-hydroxy-4-(2-methyl-1-oxobutyl)-
2,2,6,6-tetramethyl-4-cyclohexene-1,3-dione, RN 7375-66-8]
was obtained as a pale yellow oil (yield 70%): found C 67.35%
H 8.19%, calcd for C15H22O4, C 67.64% H 8.33%. Si gel TLC Rf
0.56 (9:1 hexane-EtOAc, UV/vis); UV (MeOH) λmax (log ꢀ) 279
(4.04), 238 (3.83) nm; IR (CHCl3, film) νmax 2978, 2931, 2872,
1719, 1672, 1549, 1467, 1425, 1378, 1308, 1232, 1044, 961, 873,
850, 767 cm-1; EIMS 70 eV 266 [M]+ (100), 251 (48), 233 (19),
209 (34), 196 (75), 178 (32), 163 (20) 140 (23), 113 (22), 96 (54),
1
81 (21), 70 (35), 57 (79) 43 (48); H NMR δ 18.46 (OH, s, 2′-
OH), 3.62 (H, sextet, J ) 7 Hz, H-2), 1.75 (H, m, W1/2 ) 2.4
Hz, J ) 7 Hz, H-3), 1.43 (H, m (hidden15), H-3), 1.45 (3H, s,
3′-CH3), 1.44 (3H, s, 3′-CH3), 1.37 (3H, s, 5′-CH3), 1.36 (3H, s,
5′-CH3), 1.18 (3H, d, J ) 7 Hz, H-5), 0.92 (3H, t, J ) 7 Hz,
H-4); 13C NMR in Table 1.
Papuanone [6, 5-hydroxy-4-(1-oxohexyl)-2,2,6,6-tetramethyl-
4-cyclohexene-1,3-dione] was obtained as a pale yellow oil
(yield 70%): found C 68.73% H 8.73% calcd for C16H24O4, C
68.55% H 8.63%. Si gel TLC Rf 0.46 (9:1 hexane-EtOAc, UV/
vis); UV (MeOH) λmax (log ꢀ) 282 (3.99), 238 (3.72) nm; IR
(CHCl3, film) νmax 2942, 2872, 1713, 1666, 1596, 1555, 1472,
1420, 1378, 1308, 1226, 1161, 1049, 961, 861, 767 cm-1; EIMS
(14) Borisov, E. V.; Zhang, W.; Bolvig, S.; Hansen, P. E. Magn. Reson.
Chem. 1998, 36, S104-S110.
(15) Signal was assigned by COSY NMR analysis.
NP980350N