VALEEV et al.
1292
16.68 (CH3), 17.43 and 17.63 (CH3), 28.69 and 28.90
(C3), 31.84 and 32.07 (C4), 35.37 and 35.64 (C2), 67.90
(C1), 75.87 and 76.25 (C5), 110.88 and 111.14 (C7),
147.46 and 147.58 (C6). Mass spectrum, m/z (Irel, %):
158 (0.5) [M]+, 140 (5) [M – H2O]+, 125 (10) [M –
H2O – CH3]+, 109 (3), 101 (4), 97 (5), 84 (9), 72 (11),
71 (100) [CH2=CMeC=OH]+, 70 (18), 57 (10), 55 (29).
mixture was stirred for 1 h at room temperature (until
the initial compound disappeared according to the TLC
data). The mixture was then treated with 60 ml of
water, stirred for 15 min, saturated with sodium
chloride, and extracted with ethyl acetate (3×30 ml).
The combined extracts were dried over MgSO4,
filtered, and evaporated, and the residue was purified
by column chromatography on silica gel using ethyl
acetate–petroleum ether (1:2) as eluent. Yield 4.5 g
(93%), light yellow liquid. IR spectrum, ν, cm–1: 3449,
(2Z)-2,6-Dimethylhepta-2,6-diene-1,5-diol (XI).
[α]D20 = –5.9° (c = 1.05, CHCl3). H NMR spectrum, δ,
1
ppm: 1.75 s (3H, 6-CH3), 1.85 s (3H, 2-CH3), 2.28–
2.40 m (2H, 4-H), 2.52 br.s (2H, OH), 3.95 d and
4.18 d (1H each, 1-H, J = 11.6 Hz), 4.06 d.d (1H, 5-H,
J = 4.1, 7.8 Hz), 4.86 d and 4.98 d (1H each, 7-H, J =
0.87 Hz), 5.35 t (1H, 3-H, J = 7.1 Hz). 13C NMR spec-
trum, δC, ppm: 18.24 (CH3), 22.42 (CH3), 33.57 (C4),
61.18 (C1), 74.33 (C5), 110.75 (C7), 123.96 (C3),
138.61 (C2), 147.18 (C6).
1
2951, 2927, 1715. H NMR spectrum, δ, ppm: 1.36 s
and 1.38 s (3H, 2′-CH3), 1.70–1.75 m (1H, 5-H), 1.93 s
(3H, 2-CH3), 2.64–2.82 m (4H, 3′-H, 4-H), 3.53–
3.57 m and 3.71–3.75 m (1H each, 6-H), 3.75 s (3H,
OCH3), 5.93–5.99 m (1H, 3-H). 13C NMR spectrum,
δC, ppm: 18.52 (2-CH3), 19.94 and 20.66 (2′-CH3),
27.68 and 28.12 (C4), 46.86 (C5), 51.59 (OCH3), 53.08
(C3′), 58.31 and 58.99 (C2′), 62.65 and 62.74 (C6),
128.61 and 128.77 (C2), 140.59 and 140.80 (C3),
168.78 (C1).
Methyl (2Z,5R)-2-methyl-5-(2-methyloxiran-2-
yl)-6-oxohex-2-enoate (XIV). Lead tetraacetate,
13.4 g (30.3 mmol), was added under stirring at 5°C
to a solution of 4.6 g (25.2 mmol) of isomer mixture
IXa/IXb in 30 ml of methanol–benzene (1 :1), the
mixture was stirred for 20 min at room temperature,
0.32 g (5.1 mmol) of ethylene glycol and 20 ml of
water were added, and the mixture was stirred for
10 min and treated with ethyl acetate. The extract was
dried over MgSO4, filtered, and evaporated, and the
residue was purified by column chromatography on
silica gel using ethyl acetate–petroleum ether (1:3) as
eluent. Yield 4.8 g (89%), yellow viscous liquid. IR
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1
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δC, ppm: 19.17 and 19.29 (2-CH3), 20.52 (2′-CH3),
25.47 and 25.76 (C4), 51.34 (OCH3), 52.31 and 52.48
(C3′), 55.92 (C2′), 57.85 and 58.32 (C5), 128.95 and
129.01 (C2), 138.87 and 138.96 (C3), 167.77 and
167.86 (C1), 201.01 and 202.07 (C6).
Methyl (2Z,5R)-6-Hydroxy-2,5-dimethyl-5-
(2-methyloxiran-2-yl)hex-2-enoate (XV). Compound
XIV, 4.8 g (22.6 mmol), was dissolved in 30 ml of
methanol, 8.4 g (22.6 mmol) of CeCl3 ·7 H2O was
added under stirring, the mixture was cooled to 5°C,
0.86 g (22.6 mmol) of NaBH4 was added, and the
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RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 47 No. 9 2011