1066
A. Miura et al. / Tetrahedron 61 (2005) 1061–1067
in vacuo. The residue was chromatographed on silica gel.
Elution with hexane/EtOAc (20:1) and toluene/EtOAc
(20:1) gave 13 (6.9 mg, 0.022 mmol, 60%), 2-epi-13
(2.7 mg, 0.0085 mmol, 23%) and des-tert-butyl-11
(2.0 mg, 0.0063 mmol, 17%) as pale yellow oils.
(MCH-H2O)C, 185, 93. HR-FABMS: calcd for C13H25O4
(MCH)C, 245.1753; found, 245.1759.
Compound 3 methyl ester. 1H NMR (600 MHz, CDCl3): dZ
0.884 (d, 3H, JZ7.0 Hz, 7-Me), 0.934 (t, 3H, JZ7.3 Hz,
H-11), 1.225 (d, 3H, JZ7.0 Hz, 2-Me), 1.36 (m, 1H), 1.45
(m, 2H), 1.54 (m, 1H), 1.65–1.75 (m, 2H), 1.83 (m, 2H),
1.97 (m, 1H), 2.61 (dq, 1H, JZ7.3, 7.0 Hz, 2-H), 3.31 (br,
1H, OH), 3.58 (m, 1H, 8-H), 3.68 (s, 3H, OMe), 3.94
(pseudo q, 1H, JZ7.0 Hz, 3-H), 4.10 (m, 1H, 6-H).
Compound 13. Rf: 0.57 (toluene/EtOAcZ5:1), [a]2D5 C5.38
(cZ0.14, CHCl3) 1H NMR (300 MHz, CDCl3): dZ0.896 (t,
3H, JZ7.4 Hz, 11-H), 0.936 (d, 3H, JZ7.4 Hz, 7-Me),
1.223 (d, 3H, JZ7.1 Hz, 2-Me), 1.250 (t, 3H, JZ7.1 Hz,
OCH2CH3), 1.33 (pseudo dd, 1H, JZ7.4, 10.5 Hz), 1.45–
1.54 (m, 2H), 1.62–1.72 (m, 2H), 1.80 (m, 1H), 1.86–1.99
(m, 2H), 2.04 (s, 3H, C(O)CH3), 2.45 (quint, 1H, JZ7.1 Hz,
2-H), 3.71 (pseudo dt, 1H, JZ7.7, 6.0 Hz, 6-H), 3.90
(pseudo dt, 1H, JZ8.2, 6.3 Hz, 3-H), 4.12 (q, 2H, JZ
7.2 Hz, OCH2CH3), 4.88 (pseudo dt, 1H, JZ8.2, 4.4 Hz,
8-H). IR (film): nZ2960 (s), 2875 (m), 1735 (s), 1730 (s),
1465 (m), 1375 (m), 1245 (s), 1180 (m), 1070 (m), 1015
(m). FABMS (glycerolCNOBA): m/zZ315 (MCH)C, 255
(MCCH-AcOH). HR-FABMS: calcd for C17H31O5 (MC
H)C, 315.2172; found, 315.2172.
4.1.11. (2R,3R,6S,7R,8S)-3,6-Epoxy-8-hydroxy-2,7-
dimethylundecanoic acid (2-epi-3). A solution of 2-epi-
13 (mw 314, 20.7 mg, 65.9 mmol) in 0.5 M KOH in MeOH-
H2O (1:1, 1 ml) was stirred at 20 8C for 12 h. The reaction
mixture was concentrated in vacuo and the residue was
diluted with H2O. This was washed with ether and the
aqueous layer was acidified with dil. HCl. This was
extracted with EtOAc. The organic layer was dried over
MgSO4 and concentrated in vacuo. The residue was
chromatographed on silica gel. Elution with hexane/
EtOAc (2:1) and hexane/EtOAc/AcOH (2:1:0.1) gave
2-epi-3 (12.6 mg, 51.6 mmol, 78%) as a colorless oil; [a]D26
Compound 2-Epi-13. Rf: 0.50 (toluene/EtOAcZ5:1), [a]D26
K318 (cZ0.45, CHCl3). 1H NMR (300 MHz, CDCl3): dZ
0.888 (t, 3H, JZ7.1 Hz, 11-H), 0.934 (d, 3H, JZ6.8 Hz,
7-Me), 1.094 (d, 3H, JZ6.9 Hz, 2-Me), 1.256 (t, 3H, JZ
7.1 Hz, OCH2CH3), 1.30–1.73 (m, 5H), 1.86–1.95 (m, 2H),
1.82 (m, 1H), 2.04 (s, 3H, C(O)CH3), 2.49 (dq, 1H, JZ8.2,
6.9 Hz, 2-H), 3.70 (dt, 1H, JZ7.4, 6.3 Hz, 3-H), 3.97 (dt,
1H, JZ8.2, 6.3 Hz, 3-H), 4.09–4.20 (m, 2H, OCH2CH3),
4.84 (ddd, 1H, JZ9.0, 5.0, 3.6 Hz, 8-H). 13C NMR
(75 MHz, CDCl3): dZ10.18, 13.28, 13.96, 14.23, 18.89,
21.29, 28.55, 29.38, 31.85, 41.58, 45.26, 60.24, 76.03,
80.24, 80.34, 170.80, 174.98. IR (film): nZ2960 (s), 2875
(m), 1735 (s), 1465 (m), 1380 (m), 1245 (s), 1070 (m), 1020
(m). FABMS (NOBA): m/zZ315 (MCH)C. FABMS
(glycerolCNOBA): m/zZ315 (MCH)C, 255 (MCH-
AcOH)C. HR-FABMS: calcd for C17H31O5 (MCH)C,
315.2172; found, 315.2177.
1
K17.38 (cZ0.375, CHCl3). H NMR (500 MHz, CDCl3):
dZ0.911 (t, 3H, JZ7.1 Hz, 11-H), 0.923 (d, 3H, JZ7.1 Hz,
7-Me), 1.168 (d, 3H, JZ6.9 Hz, 2-Me), 1.35 (m, 1H, H-10),
1.4–1.6 (m, 3H, H-9, 10), 1.64 (m, 1H, H-4), 1.76 (m, 1H,
H-5), 1.83 (m, 1H, H-7), 1.87 (m, 1H, H-5), 2.03 (m, 1H,
H-4), 2.54 (d of quint, 1H, JZ8.2, 6.9 Hz, H-2), 3.61
(pseudo dt, 1H, JZ4.9, 6.6 Hz, H-8), 3.95 (dt, 1H, JZ8.2,
7.1 Hz, H-3), 4.18 (ddd, JZ7.7, 7.1, 3.3 Hz, 1H, H-6). 13C
NMR (150 MHz, CDCl3): dZ12.03 (7-Me), 13.69 (2-Me),
14.18 (11), 18.72 (10), 26.75 (5), 29.01 (4), 37.20 (9), 39.85
(7), 44.57 (2), 73.98 (8), 80.86 (3), 81.42 (6), 177.08 (1). IR
(film): nZ3700–2200 (br, s), 1710 (s), 1200 (s), 1170 (s),
665 (m). FABMS (glycerol): m/zZ245 (MCH)C, 227
(MCH-H2O)C, 154, 136. HR-FABMS: calcd for C13H25O4
(MCH)C, 245.1753; found, 245.1757.
1
2-Epi-3 methyl ester. H NMR (600 MHz, CDCl3): dZ
0.891 (d, 3H, JZ7.0 Hz, 7-Me), 0.927 (t, 3H, JZ7.3 Hz,
H-11), 1.135 (d, 3H, JZ7.0 Hz, 2-Me), 1.36 (m, 1H), 1.44
(m, 2H), 1.48–1.64 (m, 2H), 1.75 (m, 1H), 1.8–1.9 (m, 2H),
1.99 (m, 1H), 2.56 (m, 1H, 2-H), 3.32 (d, 1H, JZ4.7 Hz,
OH), 3.57 (m, 1H, 8-H), 3.69 (s, 3H, OMe), 3.95 (pseudo q,
1H, JZ7.0 Hz, 3-H), 4.12 (m, 1H, 6-H).
4.1.10. (2S,3R,6S,7R,8S)-3,6-Epoxy-8-hydroxy-2,7-
dimethylundecanoic acid (3). A solution of 13 (mw 314,
6.3 mg, 20 mmol) in 0.5 M KOH in MeOH-H2O (1:1, 1 ml)
was stirred at 20 8C for 12 h. The reaction mixture was
concentrated in vacuo and the residue was diluted with H2O.
This was washed with ether and the aqueous layer was
acidified with dil. HCl. This was extracted with EtOAc. The
organic layer was dried over MgSO4 and concentrated in
vacuo. The residue was chromatographed on silica gel.
Elution with hexane/EtOAc (4:1) and hexane/EtOAc/AcOH
(2:1:0.1) gave 3 (5.0 mg, 20 mmol, quant.) as a colorless oil;
[a]2D7 C8.08 (cZ0.25, CHCl3). 1H NMR (600 MHz,
CDCl3): dZ0.902 (d, 3H, JZ7.1 Hz, 7-Me), 0.931 (t, 3H,
JZ7.0 Hz, H-11), 1.221 (d, 3H, JZ7.0 Hz, 2-Me), 1.35 (m,
1H, H-10), 1.45–1.55 (m, 3H, 10-H), 1.68–1.8 (m, 2H), 1.8–
1.92 (m, 2H), 2.00 (m, 1H, 4-H), 2.72 (quint, 1H, JZ6.8 Hz,
2-H), 3.63 (pseudo q, 1H, JZ5.9 Hz, 8-H), 3.97 (pseudo q,
1H, JZ6.8 Hz, 3-H), 4.12 (m, 1H, 6-H). 13C NMR
(150 MHz, CDCl3): dZ12.05, 13.49, 14.18, 18.62, 26.74,
27.99, 37.23, 39.86, 43.25, 73.73, 80.20, 81.45, 177.06. IR
(film): nZ3700–2200 (br, s), 1710 (s), 1260 (s), 1170 (s),
665 (m). FABMS (glycerol): m/zZ245 (MCH)C, 227
Acknowledgements
We appreciate the assistance of Mrs Teiko Yamada for
measuring NMR and mass spectra. Financial support by
grant-in-aid from Japan Society for the Promotion of
Science (No. 11760083), The Agricultural Chemical
Research Foundation, Intelligent Cosmos Foundation and
The Naito Foundation is gratefully acknowledged.
References and notes
1. (a) McCann, P. A.; Pogell, B. M. J. Antibiot. 1979, 32,