84
E.N. Dubis et al. / Journal of Molecular Structure 596 02001) 83±88
converted to absorbance spectra, and baseline drift
was removed using the instrument software
/OMNIC 3.0). In some cases, smoothing procedure
was required.
Lipid extract was prepared by the treatment of fresh
leaves with chloroform /15 s), followed by the
addition of drying agent /anhydrous MgSO4), and
evaporation of the solvent. Cuticular waxes were
investigated in the HATR mode. A wax solution in
acetone was deposited on the surface of the ZnSe
crystal. Solvent was evaporated at room temperature
and the sample was then heated to 808C for 3 min in
order to completely remove the solvent [7].
3.2. 2-Phenylethyl myristate 02-PEM) Ð spectroscopic
data:
1H NMR /ppm): 7.26 /5H, m, Ar±H); 4.30 /2H, t,
Ar±CH2±); 3.01 /2H, t, ±COCH2±); 2.29 /2H, t, ±
CH2±); 1.60 /2H, dt, ±CH2±);1.27 /20H, m, /CH2)10);
0.86 /3H, t, ±CH3). 13C NMR /ppm): 173.74/C);
137.03/CH);128.85/CH); 128.40 /CH); 126.46
/CH2); 64.63 /CH2); 34.28 /CH2); 31.88 /CH2);
29.65 /CH2); 29.62 /CH2); 29.57 /CH2); 29.41
/CH2); 29.33 /CH2); 29.23 /CH2); 29.07 /CH2);
14.09 /CH3). IR /CHCl3, cm21): 3087, 3064,
3029,2923, 2853, 1736, 1655, 1605, 1497, 1466,
1455, 747, 723, 699.
Fresh leaves of hops /Humulus lupulus) were
collected from garden cultivation in Biaøystok.
4. Synthesis of docosyl benzoate
3. Synthesis of phenylmethanol and 2-phenylethanol
esters of C14 myristic acid
Benzoil chloride was added to a stirred solution of
docosyl alcohol /C22 long) in pyridine. The reaction
mixture was then heated for 1 h. After cooling and
removing the solvent, the residue was then subjected
to column chromatography on silica gel using a
hexane: ether /93:7; V:V) mixture as an eluent.
Yield of pure ester was 75%.
100 mg /4.3 £ 1024 mole) of myristic acid /C14
long) was dissolved in 2 ml of dichloromethane and
cooled in an ice bath. 0.1 ml ꢀ8 £ 1024mol of oxalyl
chloride and a drop of DMF were added and the
resulting mixture was stirred until it was brought
down to room temperature. After evaporation of the
solvent /CH2Cl2), 0.1 g ꢀ8:6 £ 1024mol of phenyl-
methanol or 2-phenylethanol in pyridine was added.
The mixture was warmed for 30 min. After cooling,
the solvent was evaporated and the residue was
subjected to column chromatography on aluminium
oxide using CH2Cl2 as an eluent. Yield of pure ester
was 80%.
4.1. Docosyl benzoate ± spectroscopic data:
1H NMR /ppm): 8.07 /2H, d, Ar±H); 7.40 /3H,
m,Ar±H); 4.32 /2H, t,±COCH2±); 1.77 /2H, dt, ±
CH2±); 1.26 /18H, m, /CH2)9); 0.86 /3H, t, ±CH3).
13C NMR /ppm): 166.67/C); 132.76/CH);
129.52/CH); 128.29/CH); 65.14/CH2); 31.92/CH2);
29.69/CH2); 29.58/CH2); 29.53/CH2); 29.36/CH2);
29.29/CH2); 28.71/CH2); 14.12 /CH3). IR /CHCl3,
cm21): 3090, 3061, 3033, 2954, 2916, 2849, 1720,
1602, 1585, 1469, 1275, 1111, 709.
3.1. Phenylmethyl myristate 0PMM) Ð spectroscopic
data:
1H NMR /ppm): 7.36 /5H, m, Ar±H); 5.12 /2H, s,
Ar±CH2±); 2.36 /2H, t, ±COCH2±); 1.65 /2H, dt, ±
CH2±); 1.26 /20H, m, /CH2)10); 0.85 /3H, t, ±CH3).
13C NMR /ppm): 173.69/C); 136.11 /CH); 129.51
/CH); 128.13 /CH); 66.02 /CH2); 34.31 /CH2);
31.90 /CH2); 29.64 /CH2); 29.62 /CH2); 29.57
/CH2); 29.42 /CH2); 29.33 /CH2); 29.23 /CH2);
29.10 /CH2); 14.10 /CH3). IR /CHCl3, cm21): 3091,
3066, 3034, 2923, 2853, 1738, 1655,1498, 1456,
1161, 733, 696.
5. Results and discussion
In our research, we performed spectroscopic studies
of fresh hops /Humulus lupulus) leaves and their lipid
extract, which is known to contain aromatic
compounds [4]. Reference standards of the aromatic
esters phenylmethyl mirystate, 2-phenylethyl mirys-
tate and docosyl benzoate were synthesized and
analysed using the HATR technique. For the analysis
of aromatic components, the C±H out-of-plane