Journal of Agricultural and Food Chemistry
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temperature, 250 °C; transfer line temperature, 280 °C; carrier gas,
helium at a constant flow rate of 1 mL/min; split ratio, 1:50.
The injection was repeated with 0.5 μL of the extract in a GC-MS
6890/5973 (Agilent) equipped with a polar SWax capillary column
(30 m × 0.25 mm, film thickness = 0.25 μm, Supelco). The
temperature program was as follows: 50 °C, 5 min isotherm, and then
5 °C/min to 240 °C; injector temperature, 250 °C; transfer line
temperature, 280 °C; carrier gas, helium at a constant flow rate of 1
mL/min; split ratio, 1:50.
“MS peak.” In the case of coelutions, the ratios of the coeluting
compounds were estimated via the acquisition done on polar phase.
Minor peaks were noted as trace amounts (tr) in Table 1.
Authentic Samples: Preparation of ( )-(Z)-1,5-Octadien-3-ol
39. (E)-Oct-2-en-5-yn-1-ol 115. A solution of 114 (17 g, 139.1 mmol)
in Et2O (30 mL) was added dropwise to a suspension of LiAlH4 (4.5 g,
118.7 mmol) in Et2O (380 mL) at 0 °C. After 18 h, H2O (4.5 mL),
15% aqueous NaOH (4.5 mL), and H2O (45 mL) were added
successively, and the reaction mixture was filtered through a Buchner
̈
funnel and then dried (Na2SO4) and concentrated. Bulb-to-bulb
distillation afforded pure 115 in an 81% yield: bp, 81 °C/0.4 mbar; IR,
3321, 2975, 2936, 2918, 2878, 1672, 1455, 1421, 1374, 1321, 1270,
1223, 1092, 1061, 995, 968, 892, 781; 1H NMR, δ 1.14 (t, J = 7.5 Hz,
3H); 1.68 (br s, 1 OH); 2.20 (tq, J = 2.2, 7.5 Hz, 2H); 2.92−2.95 (m,
2H); 4.13 (dd, J = 1.2, 5.9 Hz, 2H); 5.66−5.73 (m, 1H); 5.87−5.95
(m, 1H); 13C NMR, δ 12.4 (t); 14.2 (q); 21.8 (t); 63.2 (t); 76.0 (s);
84.2 (s); 127.3 (d); 130.3 (d); MS (EI, 70 eV), 124 (2, M+•); 123 (8);
109 (35); 95 (79); 91 (66); 81 (18); 79 (100); 78 (22); 77 (77); 67
(34); 65 (30); 57 (32); 55 (17); 53 (22); 51 (19); 41 (29); 39 (30).
( )-(3-(Pent-2-ynyl)oxiran-2-yl)methanol 116. tert-Butyl hydro-
peroxide (70%, 13.8 g, 107.2 mmol) was added dropwise at 25 °C to a
solution of vanadyl acetylacetonate (VO(acac)2), 208 mg, 0.78 mmol)
and 115 (6.5 g, 52.33 mmol) in toluene (160 mL). After 5 h, the
reaction mixture was diluted with Et2O, washed with 15% aqueous
NaHCO3 and then with H2O to neutrality, dried (Na2SO4),and
concentrated. Bulb-to-bulb distillation afforded pure 116 in a 90%
yield: bp, 70 °C/0.3 mbar; IR, 3416, 2976, 2919, 2878, 2211, 1681,
1455, 1420, 1364, 1320, 1294, 1195, 1083, 1016, 941, 918, 857, 777,
703, 639; 1H NMR, δ 1.11 (t, J = 7.6 Hz, 3H); 1.25 (m, 1 OH); 2.16
(tq, J = 2.5, 7.6 Hz, 2H); 2.54 (qquint, J = 2.5, 17.4 Hz, 2H); 3.10−
3.14 (m, 2H); 3.64 (dd, J = 4.1, 12.5 Hz, 1H); 3.94 (dd, J = 2.5, 12.5
Hz, 1H); 13C NMR, δ 12.4 (t); 14.0 (q); 21.7 (t); 53.7 (d); 58.0 (d);
61.3 (t); 73.4 (s); 84.2 (s); MS (EI, 70 eV), 140 (0, M+•); 121 (10);
111 (21); 109 (100); 107 (24); 95 (29); 93 (12); 91 (22); 83 (21); 81
(42); 79 (69); 77 (59); 67 (66); 65 (43); 57 (36); 55 (32); 53 (54);
51 (29); 43 (26); 41 (78); 39 (52).
Mass spectra were generated at 70 eV at a scan range from m/z 27
to 350. Linear retention indices (LRIs) were determined after injection
of a series of n-alkanes (C5−C28) under identical conditions.
Identification of Components. The compounds listed in Table 1
were identified by comparison of their mass spectra and LRIs obtained
from a proprietary database. If only one method was applied (MS data
alone or LRI alone), the identification was tentative. This database is
composed of analytical data obtained from synthesized or
commercially available compounds that were unequivocally charac-
terized by GC-MS and NMR spectroscopy. The commercial sources
or synthetic procedures of all the identified compounds are given
above under Chemicals.
GC−Olfactometry. The sniffing experiments were performed by
three trained panelists, who were asked to use free vocabulary to
describe odors perceived at the sniffing port. The panelists repeated
the experiments on nonpolar and polar columns. Only the odors
detected by at least two of the three panelists and described with very
similar descriptors are reported in Tables 2 and 3. Odorants were
identified by comparison of their LRIs, mass spectra, and odor
characteristics with the data of the reference compounds.
GC−Olfactometry on Nonpolar Column. A 1 μL aliquot of extract
was injected into a GC-MS 6890-5973N (Agilent) equipped with a
HP-1 capillary column (60 m × 0.32 mm, film thickness = 1 μm,
Agilent) and a sniffing port. The temperature program was as follows:
50 °C, 5 min isotherm, and then 3 °C/min to 120 °C followed by 5
°C/min to 250 °C; injector temperature, 250 °C; carrier gas, helium at
a constant flow rate of 2.7 mL/min; split ratio, 1:1. The column
effluent was split 1:5 into an MS detector and a heated sniffing port.
GC−Olfactometry on Polar Column. A 1 μL aliquot of extract was
injected into a GC-FID Varian 380 equipped with a DBWax megabore
column (30 m × 0.53 mm, film thickness = 1 μm, J&W Scientific,
Folsom, CA, USA) and a sniffing port. The temperature program was
as follows: 50 °C, 5 min isotherm, and then 5 °C/min to 240 °C;
injector temperature, 250 °C; carrier gas, helium at constant flow rate
of 5 mL/min; split ratio, 1:10. The column effluent was split 1:10 into
a flame ionization detector (FID) and a heated sniffing port.
Quantitation by GC. The oyster leaf extract was injected into a
GC 6890 (Agilent) equipped with a double injector and two nonpolar
DB-1 capillary columns (60 m × 0.25 mm, film thickness = 0.25 μm,
J&W 122-1062). One column was connected to an MS 5973N
(Agilent) for identification and the other to an FID for quantitation.
The temperature program was as follows: 50 °C for 5 min, increased
to 120 °C at a rate of 3 °C/min, then increased to 250 °C at a rate of 5
°C/min, 5 min isothermal, then increased to 300 °C at a rate of 15
°C/min, and then 20 min isothermal; split ratio, 1:10; injection
volume, 0.2 μL; injector and detector temperatures, both 250 °C;
carrier gas, helium at constant flow rates of 1.8 and 2.1 mL/min,
respectively. For the quantitative data given in Table 1, the oyster leaf
extract (17.0 mg) was diluted 10 times in dichloromethane with
methyl octanoate (6.0 mg) as an internal standard. The major
components (>0.05 FID %) were quantified. Their percentages were
obtained from the FID area corrected with the use of the response
factors, previously measured with pure standards under the same
conditions or calculated according to the method of de Saint Laumer
et al.15 The relative response factors (RRFs) were calculated as
follows: RRF = (mcompound × areaISTD)/(mISTD × area-
compound), where mcompound and areacompound are the mass
and corresponding GC peak area of the analyte and mISTD and
areaISTD are the mass and GC peak area of the internal standard.
With this instrument configuration, the simultaneous injection of the
extract on both columns allowed us to assign each “FID peak” to an
( )-(Z)-(3-(Pent-2-enyl)oxiran-2-yl)methanol 117. A solution of
116 (5 g, 35.66 mmol) in toluene (100 mL) was hydrogenated over a
Lindlar catalyst (1.0 g). After absorption of 870 mL, the reaction
mixture was filtered and concentrated. Bulb-to-bulb distillation
afforded 117 in a 96% yield: bp, 73 °C/0.25 mbar; IR, 3412, 3011,
2963, 2933, 2874, 1654, 1462, 1403, 1374, 1309, 1282, 1209, 1079,
1
1023, 977, 940, 908, 858, 814, 794, 719, 640; H NMR, δ 0.97 (t, J =
7.7 Hz, 3H); 2.05 (quint, J = 7.7 Hz, 2H); 2.28−2.44 (m, 3H); 2.95−
3.01 (m, 2H); 3.61 (dd, J = 4.5, 12.8 Hz, 1H); 3.90 (dd, J = 2.5, 12.8
Hz, 1H); 5.32−5.39 (m, 1H); 5.50−5.58 (m, 1H); 13C NMR, δ 14.2
(q); 20.7 (t); 29.2 (t); 55.3 (d); 58.2 (d); 61.7 (t); 122.3 (d); 134.9
(d); MS (EI, 70 eV), 142 (0, M+•); 127 (1); 111 (15); 95 (16); 93
(17); 91 (10); 83 (21); 82 (35); 81 (40); 79 (22); 77 (10); 69 (38);
68 (45); 67 (100); 65 (10); 61 (12); 57 (23); 56 (11); 55 (68); 54
(18); 53 (21); 43 (31); 41 (75); 39 (32).
( )-(Z)-1,5-Octadien-3-ol 39. In a 250 mL flask under N2, Zn
powder (7.3 g, 0.112 mmol) was added to a solution of (C5H5)2TiCl2
(bis(cyclopentadienyl)titanium dichloride, 6.7 g, 27 mmol) in
tetrahydrofuran (THF) (150 mL), followed by ZnCl2 (3.68 g, 27
mmol). After 40 min at 20 °C, a solution of the epoxy alcohol 117 (3.2
g, 22.5 mmol) in THF (15 mL) was added to the green solution. After
45 min at 20 °C, the blue reaction mixture was quenched by the
addition of 1% aqueous H2SO4 (100 mL) and then extracted with
Et2O (3 × 100 mL). The organic phase was washed to neutrality with
H2O, dried (Na2SO4), concentrated, and purified by bulb-to bulb
distillation (bp, 78 °C/8 mbar) to afford 1.31 g of 39 (94% purity by
GC-MS, containing 2.4% of (E)-1,5-octadien-3-ol 37) in a 46% yield:
IR, 3349, 3080, 3011, 2963, 2934, 2875, 1645, 1456, 1423, 1405, 1305,
1203, 1126, 1034, 989, 919, 866, 792, 715; 1H NMR, δ 0.97 (t, J = 7.7
Hz, 3H); 1.77 (br s, 1 OH); 2.04−2.11 (m, 2H); 2.29−2.34 (m, 2H);
4.09−4.18 (m, 1H); 5.12 (dt, J = 1.4, 10.5 Hz, 1H); 5.25 (dt, J = 1.4,
16.5 Hz, 1H); 5.32−5.40 (m, 1H); 5.54−5.60 (m, 1H); 5.90 (ddd, J =
5.6, 10.5, 16.5 Hz, 1H); 13C NMR, δ 14.2 (q); 20.7 (t); 35.0 (t); 72.5
(d); 114.7 (t); 123.7 (d); 135.3 (d); 140.5 (d); MS (EI, 70 eV), m/z
11686
dx.doi.org/10.1021/jf303395q | J. Agric. Food Chem. 2012, 60, 11681−11690
Delort, Estelle
