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Escriba et al.
4850 J. Agric. Food Chem., Vol. 57, No. 11, 2009
in a tandem Finkelstein transposition-elimination reaction pro-
moted by NaI in a further step. This process allows the use of
glycerol as a starting material, avoiding the use of reagents such as
allylic alcohol, an irritant compound, and fatty acid acyl chlor-
ides. The synthesis of the intermediate compounds can also be
carried out by an alternative synthesis. Researchers from Dow
Global Technologies recently described its synthesis starting from
glycerol, carboxylic acids, and hydrogen chloride with a partial
pressure of >15 psi (17). A mixture of glycerol, carboxylic acid,
and metal halide in an ionic liquid leads also to the same
intermediates (18). Nevertheless, using CTMS results in obtain-
ing the allyl ester precursors in high purity. Yields were also high
in most of the reactions assayed. Once the allyl esters of medium-
and long-chain fatty acids were obtained, their ovicidal activity
against eggs of C. pomonella was tested. A set of experiments
using different concentrations of each allyl ester was carried
out to evaluate the efficacy and the growth regulator activity on
C. pomonella eggs.
glycerol (5.52 g, 60 mmol), and CTMS (25 mL, 200 mmol) to give
1,3-dichloro-2-propyl butanoate 3a (2.59 g, yield 67%). Compound
3a (0.52 g, 2.6 mmol) and sodium iodide (11.55 g; 77 mmol) in dried
butanone (7.6 mL) gave allyl butanoate 4a (288 mg, yield 86%) (distilla-
tion at 50-71 °C, 20 mbar).
Allyl hexanoate (4b). [CAS Registry No. 123-68-2] was prepared
following the general procedure from hexanoic acid 2b (2.32 g, 20 mmol),
glycerol (5.50 g, 60 mmol), and CTMS (25 mL, 200 mmol) to give
1,3-dichloro-2-propyl hexanoate 3b (4.35 g, yield 96%). Compound 3b
(0.51 g, 2.2 mmol) and sodium iodide (1.33 g; 9 mmol) in dried butanone
(6.6 mL) gave allyl hexanoate 4b (189 mg, yield 54%) (distillation at 75-
98 °C, 20 mbar).
Allyl octanoate (4c). [CAS Registry No. 4230-97-1] was prepared
following the general procedure from octanoic acid 2c (2.88 g, 20 mmol),
glycerol (5.61 g, 60 mmol), and CTMS (25 mL, 200 mmol) to give
1,3-dichloro-2-propyl octanoate 3c (4.26 g, yield 84%). Compound 3c
(380 mg, 1.5 mmol) and sodium iodide (0.6 g; 4 mmol) in dried butanone
(3 mL) gave allyl octanoate 4c (257 mg, yield 94%) (distillation at 90-
105 °C, 7 mbar).
Allyl decanoate (4d). [CAS Registry No. 57856-81-2] was prepared
following the general procedure from decanoic acid 2d (1.72 g, 10 mmol),
glycerol (1.85 g, 20 mmol), and CTMS (6.35 mL, 50 mmol) to give
1,3-dichloro-2-propyl decanoate 3d (2.75 g yield 97%). The crude com-
pound (0.28 g, 1 mmol) and sodium iodide (0.6 g; 4 mmol) in dried
butanone (3 mL) gave allyl decanoate 4d (177 mg, 84%).
MATERIALS AND METHODS
Chemicals. Butanone was purchased from Acros and dried over
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molecular sieves (3 A) according to the conventional method prior to
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use. Sodium iodide was purchased from Riedel-de Haen and dried by
Allyl dodecanoate (4e). [CAS Registry No. 7003-75-0] was prepared
following the general procedure from dodecanoic acid 20 (4.1 g, 20 mmol),
glycerol (5.53 g, 60 mmol), and CTMS (25 mL, 200 mmol) to give
1,3-dichloro-2-propyl dodecanoate 3e (6.19 g, yield 96%). The crude
compound (6.2 g, 20 mmol) and sodium iodide (11.9 g; 80 mmol) in dried
butanone (30 mL) gave allyl dodecanoate 4e (4.08 g, 89%).
heating at 110 °C for 24 h. Chlorotrimethylsilane (CTMS), glycerol,
and the other fatty acids were purchased from Fluka (Sigma-Aldrich
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Quimica, S.A., Madrid, Spain) and used as received. t-Butyl methyl ether
was purchased from J. T. Baker (Quimega, Lleida, Spain). Anhydrous
magnesium sulfate (MgSO4) was purchased from Panreac (Barcelona,
Spain).
Allyl tetradecanoate (4f ). [CAS Registry No. 45236-96-2] was pre-
pared following the general procedure from tetradecanoic acid 2f (4.58 g,
20 mmol), glycerol (5.69 g, 62 mmol), and CTMS (25 mL, 200 mmol) to give
1,3-dichloro-2-propyl tetradecanoate 3f (6.79 g, yield 98%). The crude
compound (6.62 g, 20 mmol) and sodium iodide (11.64 g; 78 mmol) in dried
butanone (30 mL) gave allyl tetradecanoate 4f (5.01 g, 99%).
Apparatus. NMR spectra were recorded on a Varian 400 spectrometer
(400 MHz for 1H and 100 MHz for 13C). Chemical shifts are reported in
delta units (δ), parts per million (ppm) relative to the singlet at 7.26 ppm of
CDCl3 for 1H and the center line of the triplet at 77.00 ppm for 13C NMR:
The following abbreviations are used: s, singlet; d, doublet; t, triplet; q,
quartet; quin, quintet; m, multiplet. GC-MS was performed in an Agilent
6890N GC coupled to a 5973 mass selective detector (Agilent Technologies
Allyl hexadecanoate (4g). [CAS Registry No. 43211-62-7] was pre-
pared following the general procedure from hexadecanoic acid 2g (3.04 g,
12 mmol), glycerol (2.86 mg, 31 mmol), and CTMS (7.5 mL, 60 mmol) to
give 1,3-dichloro-2-propyl hexadecanoate 3g (3.43 g, yield 77%). The crude
compound (0.37 g, 1 mmol) and sodium iodide (0.6 g; 4 mmol) in dried
butanone (3 mL) gave allyl hexadecanoate 4g (287 mg, 100%).
~
Espana, S.L., Las Rozas, Spain) and equipped with a DB5-MS column
(J&W, Anorsa, Barcelona, Spain) (30 m  0.25 mm  0.25 μm). The
following chromatographic conditions were used: injection volume, 1 μL;
constant flow, 2 mL/min with He as the carrier gas; split injection ratio,
20:1 at 280 °C. The oven temperature program started at 50 °C for 5 min;
the temperature was increased at 5 °C/min to 110 °C and then increased at
10 °C/min until holding at the final temperature of 260 °C for 15 min. MS
acquisition parameters were scan mode from m/z 50 to 600, 280 °C
interface temperature, and 1200 V resulting EM voltage.
Allyl octadecanoate (4h). [CAS Registry No. 6289-31-2] was prepared
following the general procedure from octadecanoic acid 2h (5.65 g,
20 mmol), glycerol (5.57 g, 60 mmol), and CTMS (25 mL, 200 mmol) to
give 1,3-dichloro-2-propyl octadecanoate 3h (7.85 g, yield 97%). The crude
compound (7.85 g, 20 mmol) and sodium iodide (11.8 g; 79 mmol) in dried
butanone (30 mL) gave allyl octadecanoate 4h (6.11 mg, 99%).
Synthesis of Allyl Esters (General Procedure). Carboxylic acid
(1 mmol) 2a-h, glycerol (2 mmol), and CTMS (5 mmol) were mixed in a
15 mL reaction vial fitted with a PTFE-lined cap. The mixture was heated
at 80 °C for 48 h in a digestion stirrer block. After cooling, t-butyl methyl
ether was added, and the mixture was washed three times with water. The
organic layer was dried (MgSO4), filtered, and evaporated under vacuum
to give the corresponding crude compound. The crude product was used in
the next step without further purification. A solution of that 1,3-dichloro-
2-propyl ester (1 mmol) and sodium iodide(4 mmol) indried butanone was
heated at 115 °C for 48 h in a capped reaction vial. After cooling, t-butyl
methyl ether was added, and the mixture was filtered and then washed with
a saturated solution of sodium thiosulfate and water. The upper layer was
recovered and dried over anhydrous magnesium sulfate. The solvent was
evaporated under vacuum to give the corresponding crude compound.
The crude compound, in the case of allyl decanoate, allyl dodecanoate,
allyl tetradecanoate, allyl hexadecanoate, and allyl octadecanoate, was
purified by silica column chromatography (45 μm particle size) and eluted
with n-hexane to produce the corresponding allyl ester after solvent
Activity on C. pomonella Eggs. The C. pomonella population was
collected from an unsprayed apple tree orchard in 1993 at Lleida (north-
eastern Spain), and it has been reared since then on an agar-based
semisynthetic diet at room temperature under long-day conditions (19).
The adults were kept in cylindrical rearing cages, where the substrate for
egg laying was wax paper (Reynolds Cut-Rite wax paper). Because codling
moth adult females have a crepuscular activity, the wax paper was changed
in the evening, and the eggs were collected the following morning.
This procedure provided eggs that were <24 h old. The eggs were
individually and topically treated with a 0.1 μL drop of the compound
to be tested dissolved in pure acetone to the appropriate concentration,
using a Harvard Apparatus Pump 11 Injector (Harvard Apparatus, Inc.,
Holliston, MA). Preliminary experiments showed that a bigger size of
the drop caused >20% mortality in the acetone-treated controls, because
of the small size of codling moth eggs. Three replicates of 30 eggs each
were carried out per chemical compound and concentration tested. The
syringe was washed 10 times with pure acetone between two different
compounds. After evaporation of the solvent, the eggs of each replicate
were confined in a plastic Petri dish (9 cm diameter) lined on its bottom
with slightly wetted filter paper and sealed with parafilm. Petri dishes were
kept in a climatic chamber at 22 ( 2 °C, 60 ( 10% relative humidity, and
evaporation. Allyl butanoate, allyl hexanoate, and allyl octanoate, were
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purified by distillation under vacuum, with a Buchi Kugelrohr apparatus
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(Masso Analitica S.A., Barcelona, Spain).
Allyl butanoate (4a). [CAS Registry No. 2051-78-7] was prepared
following the general procedure from butanoic acid 2a (1.76 g, 20 mmol),