Components for Tethered Bilayer Membranes: Synthesis of Hydrophilically Substituted Phytanol Derivatives

Article abstract of DOI:10.1071/CH01111

In order to optimize the performance of the AMBRI biosensor (Nature 1997, 387, 580), a variety of hydrophilic linkers between the hydrophobic bilayer membrane and the gold surface have been synthesized. The principal components are prepared from phytanyl hemisuccinate, which is linked by repeating ethylene glycol or propylene glycol units to a second succinic acid unit. The syntheses of analogous substances in which the ester links are replaced by amide and by ether links are also described.

Full text of DOI:10.1071/CH01111

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Full Papers
Aust. J. Chem. 2001, 54, 431–438
Components for Tethered Bilayer Membranes: Synthesis of
Hydrophilically Substituted Phytanol Derivatives
Christopher J. Burns,A Leslie D. Field,A Jacqueline Morgan,A Brian J. Petteys,A
Jognandan Prashar,A Damon D. Ridley,A,B K. R. A. Samankumara SandanayakeA
and Valentina VignevichA
A Cooperative Research Centre for Molecular Engineering and Technology, School of Chemistry,
University of Sydney, N.S.W. 2006, Australia.
B Author to whom correspondence should be addressed (e-mail: d.ridley@chem.usyd.edu.au).
In order to optimize the performance of the AMBRI biosensor (Nature 1997, 387, 580), a variety of hydrophilic
linkers between the hydrophobic bilayer membrane and the gold surface have been synthesized. The principal
components are prepared from phytanyl hemisuccinate, which is linked by repeating ethylene glycol or propylene
glycol units to a second succinic acid unit. The syntheses of analogous substances in which the ester links are
replaced by amide and by ether links are also described.
Manuscript received: 30 August 2001.
Final version: 21 September 2001.
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Introduction
Analyte
The fabrication, study, and use of synthetic bilayer
membranes tethered to a solid support (known as tethered
bilayer membranes or t-BLMs) has been reported by a
number of research groups over the last decade. Such
systems have great potential as stable and robust cellular
membrane mimetics for use in the study of membrane bound
proteins[1–3] and in biosensing.[4–9] t-BLMs are generally
prepared in two steps: formation of a well ordered monolayer
on a solid support such as silicon or gold, and deposition of a
lipid layer from either a lipid solution or from lipid
vesicles.[4–12]
Receptor
Receptor
Ion channel
Bilayer
Hydrophilic region
The preparation of a novel t-BLM, as part of the
fabrication of a highly sensitive biosensor, was first reported
by our group in 1997,[6] and since that time a number of
reports on the utility of this technology have been
published.[13–15] The biosensor technology is based on a
t-BLM attached to a gold surface (through a hydrophilic
linker terminating in a disulfide group) with the small
ion-channel gramicidin embedded in both leaflets of the
bilayer. Attachment of receptors to the gramicidin channels
in the outer leaflet of the membrane, and to a stationary lipid
species attached to gold, generates the sensing surface
(Fig. 1). Binding of the analyte to the receptors renders the
upper leaflet gramicidin immobile and, therefore, limits
ion-flow across the membrane, which is measured through
the technique of impedance spectroscopy.
Fig. 1. Schematic of the AMBRI biosensor.
moiety that binds to the gold surface. The hydrophilic region
is required to provide an aqueous compartment into which
ions can flow, and other results[16] indicate the length of the
tether is important. The major component of the t-BLM is
the disulfide species (1), which constitutes about 99% of the
lipid material of the lower membrane leaflet. As part of
ongoing studies to examine the effect of changes to the
molecular components on bilayer properties and sensor
function,[16–18] it was necessary to synthesize a variety of
hydrophilic linkers attached to phytanol.
One requirement was that the various hydrophilic linkers
be of approximately equal length in order for the effect of
different types of linkers to be assessed. We wished to
Part of the t-BLM in this sensor is the hydrophilic linker
between the membrane-forming hydrocarbon and the sulfur
© CSIRO 2001
10.1071/CH01111
0004-9425/01/030431

432
C. J. Burns et al.
explore combinations of ether/ester and ether/amide linkers,
but since their conformations in the hydrophilic region could
not be predicted at the outset, we set initial goals to prepare
linkers in which the numbers of atoms in the chains were at
least similar. We report here on the syntheses of a number of
such hydrophilic linkers.
O
O
O
O
O
Phyt
O
O
O
O
OH
O
O
O
(4)
O
Phyt
O
O
O
OH
O
(5)
O
O
O
O
OR
O
Results and Discussion
Phyt
O
O
O
O
(6) R = CH2Ph
(7) R = H
Ester Derivatives of Succinic Acid
The major component (1) of the inner leaflet of the
biosensor’s bilayer membrane has previously been prepared
from the disulfide alcohol (2) through successive reaction
with succinic anhydride, tetraethylene glycol, and succinic
anhydride, prior to coupling with phytanol.[16] To prepare a
series of congeners of this compound, phytanol was reacted
with excess succinic anhydride in pyridine to generate the
hemisuccinate (3) in 56% yield. Significantly higher yields
(> 90%) were obtained for this compound when the reaction
was performed in dichloromethane in the presence of excess
triethylamine (Fig. 2).
O
O
O
O
O
TsO
O
(9)
PhCH 2
O
O
OH
(8)
O
O
O
(10)
O
O
O
PhCH2O
O
O
O
O
O
OH
PhCH 2
O
O
O
O
(11)
Fig. 3. Schematic representation of compounds (4)–(11).
To date only ethylene glycol derivatives have been used in
the hydrophilic component in the biosensor, but we required
modified hydrophilic components in order to explore the
precise function of this region in the system. Accordingly,
tripropylene glycol (12),[21] which like tetraethylene glycol
contains a 13-atom chain, was treated with the hemisuccinate
(3) in the presence of morpho-CDI/DMAP to give the
unsymmetrical diester (13) (Fig. 4).
=
Phyt
(R)
(R)
(R,S)
O
O
O
O
O
O
O
S
Phyt
O
O
O
O
O
S
Ph
O
O
(1)
O
Theothermajorcomponentsofthehydrophilicregioninthe
biosensor are derived from glycerol diphytanyl ether (14),[16]
so to complete the series we required the unsymmetrical
HO
O
S
O
O
O
S
Ph
Phyt
OH
(2)
O
(3)
Fig. 2. Schematic representation of the phytanyl group and
compounds (1)–(3).
HO
O
O
OH
(12)
O
O
The unsymmetrical succinic acid diester (4) was generated
by coupling the hemisuccinate (3) with excess ( > 5 molar
equiv.) tetraethylene glycol in the presence of DMAP
(4-dimethylaminopyridine) using either DCC (1,3-dicyclo-
hexylcarbodiimide) or morpho-CDI (1-cyclohexyl-3-(2-
morpholinoethyl)carbodiimide metho-p-toluenesulfonate)
as coupling agent. Use of an excess of diol minimized the
formation of bis-substituted products, while removal of
excess diol from the reaction mixture was easily
accomplished by washing with water.
In a similar way, the unsymmetrical diester (5) was
prepared from the hemisuccinate (3) and hexaethylene
glycol. However, because of the relative lack of availability
of heptaethylene glycol, the heptaethylene glycol analogue
(7) needed to be prepared by a multi-step process involving
protecting group chemistry.[19] Thus reaction of the anion of
the monobenzyl ether of tetraethylene glycol (8) with the
tosylate (9)[20] afforded the protected ether (10) which, on
treatment with acid, gave the monobenzyl ether of
heptaethylene glycol (11). The alcohol (11) was then coupled
with the hemisuccinate (3) to yield the benzyl ether (6).
Hydrogenolysis of this ether then afforded the desired
heptaethylene glycol derivative (7), and the overall yield
from tetraethylene glycol was satisfactory (Fig. 3).
Phyt
O
O
O
OH
O
(13)
Phyt
Phyt
O
O
Phyt
Phyt
O
O
O
OH
O
O
OH
O
(15)
(14)
Phyt
Phyt
O
O
O
O
O
O
O
O
O
OH
O
(16)
O
O
O
O
O
OH
Phyt
O
O
O
O
O
O
O
O
(17)
O
O
O
OH
Phyt
O
O
O
O
O
O
(18)
O
O
O
O
O
O
O
Phyt
O
O
O
O
OH
O
O
(19)
(20)
O
O
O
OH
Phyt
O
O
O
O
O
O
O
Phyt
Phyt
O
O
O
O
O
O
O
OH
O
O
O
O
O
O
(21)
Fig. 4. Schematic representation of compounds (12)–(21).

Components for Tethered Bilayer Membranes
433
succinate (16). Accordingly, the hemisuccinate (15) was
preparedby reactionofthediphytanyl ether(14)withsuccinic
anhydride in pyridine. Subsequent reaction of the acid with
excess hexaethylene glycol in the presence of DMAP using
morpho-CDI as coupling agent furnished the alcohol (16) in
goodyield(Fig. 4).
Coupling of the alcohols (4), (5), (7), (13) and (16) with
succinic anhydride was performed in pyridine and gave
excellent yields of the corresponding hemisuccinates (17),
(18), (19), (20) and (21) respectively (Fig. 4).
O
O
N
NH
Phyt
OH
X
Phyt
(31)
O
(32)
(29) X = OH
(30) X = NHMe
O
O
HN
O
NH
O
(33)
O
N
O
Phyt
N
O
NH
O
O
(34)
O
N
O
O
OH
All Ether and Succinamide/Ether Derivatives
Phyt
N
O
N
O
O
(35)
One of the issues with use of the hydrophilic component (1)
was the stability of the ester functional group, and to
minimize the likelihood of component degradation through
ester hydrolysis, we set out to replace ester functionality with
either ether or amide functionality.
Fig. 6. Schematic representation of compounds (29)–(35).
In order to test their effectiveness in the biosensor, these
hydrophilically substituted phytanol derivatives now need to
be attached to sulfur-containing end groups for attachment to
the gold surface. We shall report separately on the syntheses
of a variety of sulfur-containing end groups, on the
attachment of the hydrophilically substituted phytanol
derivatives, and on the performance of the modified
biosensors.
The preparation of the all-ether analogue of disulfide (1)
began with reaction of phytanyl bromide with excess of the
alkoxide formed from reaction of triethylene glycol and
sodium hydride, to afford the alcohol (22). Conversion of
this alcohol (22) into the tosylate (23), followed by reaction
of the tosylate with excess of the alkoxide generated from
tetraethylene glycol and sodium hydride, furnished the
heptaethylene glycol derivative (24). On further reaction
with the anion from triethylene glycol, the tosylate (25) of
this alcohol generated the decaethylene glycol derivative
(26), while reaction of the tosylate (25) with the anion from
tetraethylene glycol gave the undecaethylene glycol
derivative (27). This last product (27) has 33 atoms attached
to the phytanol oxygen and this compares with the 34 atoms
in the oxygen precursor to the disulfide (1) (Fig. 5).
Experimental
All reactions were performed under an atmosphere of dry nitrogen,
unless stated otherwise. Anhydrous benzene, diethyl ether,
tetrahydrofuran (THF) and toluene were obtained by distillation from
sodium benzophenone ketyl immediately prior to use. Anhydrous
dichloromethane was obtained by distillation from calcium hydride or
P2O5 immediately prior to use. Anhydrous N,N-dimethylformamide
(DMF) was obtained by stirring over calcium hydride for 24 h and
distilling under reduced pressure immediately prior to use. Anhydrous
pyridine was obtained by storing analytical-grade pyridine (Merck)
over KOH pellets.
Purifications were achieved by flash chromatography on silica gel
(0.040–0.063 mm) unless stated otherwise. Thin-layer chromatography
was performed using Merck 60 F254 plates with samples visualized by
means of iodine vapour, phosphomolybdic acid (5% in ethanol) with
heating, or under ultraviolet (254 nm) light. Purifications by preparative
high-pressure liquid chromatography (HPLC) were performed using a
Waters Model 510 chromatography pump incorporating a Waters
Differential Refractometer and an ISCO Model 226 Absorbance
detector (λ 254 nm).
O
O
Phyt
O
OR
(22) R = H
(23) R = Ts
O
O
O
O
Phyt
O
O
O
O
OR
(24) R = H
(25) R = Ts
Phyt
O
O
O
O
O
O
O
O
O
OH
(26)
Phyt
O
O
O
O
O
OR
O
O
O
O
O
O
1H Nuclear magnetic resonance (NMR) spectra were recorded on
Bruker AC-200F (200 MHz) and AMX-400 (400 MHz) spectrometers.
All samples were dissolved in CDCl3 and referenced to residual solvent
(CHCl3, 7.26 ppm). 13C NMR spectra were recorded on Bruker
AC-200F (50 MHz) and AMX-400 (100 MHz) spectrometers. All
samples were dissolved in CDCl3 and referenced on residual solvent
(CHCl3, 77.00 ppm). Infrared (IR) spectra were acquired on a
Perkin–Elmer 1600 series spectrometer and the spectra for oils were
recorded on the neat compounds between NaCl plates. Electron-
ionization (EI) mass spectra were recorded on a modified Kratos mass
spectrometer calibrated with perfluorokerosene (PFK). Chemical-
ionization (CI) mass spectra were recorded on an Hewlett Packard
5989A spectrometer with methane as the ionizing gas. Matrix-assisted
laser desorption ionization (MALDI) mass spectra were recorded on a
Fisons VG TofSpec spectrometer. Electrospray ionization (ESI) mass
spectra were recorded on a Finnigan LCQ mass spectrometer.
Molecular ion peaks and other significant peaks are quoted in
parentheses with their assignment (where applicable) and intensity (as
a percentage of the base peak). Microanalyses were performed by the
Campbell Microanalytical Laboratory, Department of Chemistry,
(27) R = H
(28) R = Ts
Fig. 5. Schematic representation of compounds (22)–(28).
The preparation of amide analogues of disulfide (1)
commenced with phytanoic acid (29).[22] Conversion into the
N-methyl amide (30) was accomplished in 70% yield by
treatment of the acid (29) with thionyl chloride and then with
methylamine. Subsequent reduction of the amide (30) with
lithium aluminium hydride afforded methylphytanylamine
(31), which on treatment with succinic anhydride gave the
hemisuccinamide (32). Chain extension was effected by
reaction of this acid amide (32) with the diamine (33)[23] and
DCC to give the amide derivative (34), which on heating
with succinic anhydride gave the acid amide (35). This
derivative (35) was the amide analogue of the ester derivative
(17) (Fig. 6).

434
C. J. Burns et al.
University of Otago, Dunedin, New Zealand. Note that some of the
hydrophilic derivatives retained moisture very strongly, and that in
these cases analytical data for partially hydrated derivatives resulted.
dropwise over 10 min to the stirred solution, and the mixture was stirred
for 4 days. The suspension was filtered and the solid urea washed with
dichloromethane. The filtrate was washed with water (20 mL), 1 M HCl
(20 mL) and brine (20 mL), and was then dried (Na2SO4). The solvent
was evaporated to give a colourless oil. Purification by chromatography
using ethyl acetate as eluent yielded the diester (5) as a colourless oil
(0.90 g, 64%) (Found: C, 65.7; H, 10.8. C36 H70O10 requires C, 65.7; H,
10.6%). IR νmax 3463(br), 2873, 1737 cm–1. 1H NMR δ 0.75–0.91, m,
15H, phytanyl CH3s; 0.91–1.72, m, 24H, phytanyl CHs and CH2s; 2.62,
m, 4H, succinyl CH2s; 3.04, s, 1H, OH; 3.56–3.73, m, 22H, OCH2CH2O;
4.10, m, 2H, CH(Me)CH2CH2O; 4.23, m, 2H, OCH2CH2OC(O). 13C
NMR δ 19.4–19.7, overlapping signals, non-terminal CH3s; 22.6, CH3;
22.7, CH3; 24.3, CH3; 24.4, CH2; 24.75, CH2; 27.9, CH; 29.0, succinyl
CH2; 29.1, succinyl CH2; 29.8, CH; 32.7, CH; 35.4, CH2; 35.5, CH2;
37.2, CH2; 37.3, CH2; 39.3, CH2; 61.7, CH2; 63.35, CH2; 63.8, CH2;
69.1, CH2; 70.3, CH2; 70.5, CH2; 72.5, CH2; 172.3, C(O). Mass
spectrum (CI) m/z663 ([M+1]+, 100%).
1-Cyclohexyl-3-(2-morpholinoethyl)carbodiimide
metho-p-tol-
uenesulfonate (morpho-CDI), dicyclohexylcarbodiimide (DCC),
4-dimethylaminopyridine (DMAP) and its hydrochloride (DMAP·HCl),
tetraethylene glycol, and hexaethylene glycol were purchased from Sig-
ma–Aldrich. Other reagents were prepared by literature methods as de-
scribed below. Phytanol was prepared as described previously as a
mixture of the 3R,7R,11R- and 3S,7R,11R-diastereomers.[22]
Phytanyl Hemisuccinate (3)
(i) Using triethylamine. Triethylamine (194 mg, 1.91 mmol) was
added to a solution of phytanol (952 mg, 3.19 mmol) and succinic
anhydride (415 mg, 4.14 mmol) in dichloromethane (20 mL). The
mixture was heated at reflux for 3 h and then was cooled to room
temperature. The solvent was removed under reduced pressure and
diethyl ether was added (50 mL). The organic layer was washed with
1M HCl (50 mL), water (50 mL), brine (50 mL) and dried (Na2SO4),
and the solvent was removed under reduced pressure to give the
hemisuccinate (3) as a colourless oil (1.23 g, 97%) (Found: C, 72.0; H,
11.9. C24H46O4 requires C, 72.3; H, 11.6%). IR νmax 3200–2900, 1738
cm–1. 1H NMR δ 0.82–0.90, m, 15H, phytanyl CH3s; 0.94–1.68, m,
24H, phytanyl CHs and CH2s; 2.57–2.73, m, 4H, succinyl CH2s;
Monobenzyl Tetraethylene Glycol (8)
A mixture of tetraethylene glycol (30 g, 205 mmol), benzyl chloride
(6.5 g, 51.3 mmol) and 40% (w/w) aqueous sodium hydroxide (15 mL)
was heated at 100°C with stirring for 24 h. The cooled reaction mixture
was diluted with water (20 mL) and extracted with ether (3×200 mL).
The combined organic extracts were washed with brine (100 mL) and
dried (Na2SO4), and the solvent was removed under reduced pressure to
give the crude material as a pale orange oil. Purification by
chromatography using ethyl acetate provided the monobenzyl ether (8)
(10.5 g, 72%) as a pale yellow oil. 1H NMR δ 2.82, br s, 1H, OH;
3.57–3.73, m, 16H, OCH2CH2O; 4.57, s, 2H, CH2Ar; 7.27–7.36, m,
5H, ArH. Mass spectrum (ESI) m/z 307 ([M+Na]+). These data were
consistent with those previously reported.[24]
4.10–4.17, m, 2H, CH(Me)CH2CH2O. 13C NMR
δ 19.4–19.7,
overlapping signals, non-terminal CH3s; 22.6, CH3; 22.7, CH3; 24.3,
CH2; 24.4, CH2; 24.8, CH2; 27.9, CH; 28.9, succinyl CH2; 29.0,
succinyl CH2; 29.8, CH; 32.7, CH; 35.4, CH2; 35.5, CH2; 37.2, CH2;
37.4, CH2; 39.3, CH2; 63.5, CH2; 172.2, C(O); 177.7, C(O)OH. Mass
spectrum (CI) m/z 399 ([M+H]+, 100%), 101 (41).
(ii) Using pyridine. Succinic anhydride (10.0 g, 10.0 mmol) was
added portionwise to a solution of phytanol (10.0 g, 33.5 mmol) in
pyridine (150 mL), and the mixture was stirred at room temperature for
3 days. The solvent was removed under vacuum, and 3 M HCl (250 mL)
was then added to the residue. The aqueous solution was extracted with
dichloromethane (3×120 mL). The combined organic extracts were
washed with water (2×100 mL), brine (150 mL) and dried (Na2SO4),
and the solvent was removed under reduced pressure to afford the
hemisuccinate (3) (7.50 g, 56%) as a pale yellow oil. The data acquired
were identical to those obtained for the preparation of the
hemisuccinate using triethylamine.
1-Benzyl-22-(tetrahydropyranyl) Heptaethylene Glycol (10)
(i) Using sodium hydride. A 60% dispersion of sodium hydride
(217 mg, 5.42 mmol) was added to the benzyl-protected polyether (8)
(1.03 g, 3.62 mmol) in THF (15 mL), and the mixture was stirred at
room temperature for 30 min. A solution of the tosylate (9)[20] (1.10 g,
4.34 mmol) in THF (10 mL) was added to the reaction mixture, which
was stirred for a further 24 h. The solvent was removed under reduced
pressure, and the residue was diluted with saturated aqueous NH4Cl
(5 mL) and water (75 mL). The aqueous solution was extracted with
dichloromethane (3×50 mL), the combined organic extracts were
washed with brine (75 mL), dried (Na2SO4) and the solvent was re-
moved under vacuum to give the crude material as a dark brown oil. Pu-
rification by chromatography using 98:2 CH2Cl2/MeOH as eluent gave
the heptaethylene glycol derivative (10) as an oil (1.29 g, 71%) (Found:
C, 61.6; H, 9.2. C26H44O9·H2O requires C, 61.6; H, 8.9%). 1H NMR δ
1.46–1.84, m, 6H, THP CH2s; 3.44–3.75, m, 28H, OCH2CH2O;
3.81–3.92, m, 2H, THP CH2O; 4.56, s, 2H, CH2Ar; 4.62, br t, J 3.4 Hz,
1H, OCH(CH2)O; 7.27–7.35, m, 5H, ArH. 13C NMR (50 MHz) δ
(CDCl3) 19.4, CH2; 25.4, CH2; 30.5, CH2; 62.2, CH2; 66.6, CH2; 69.4,
CH2; 70.6, CH2; 73.2, CH2Ar; 98.9, CH; 127.5, Ar; 127.7, Ar; 128.3,
Ar; 138.2, Ar quat. Mass spectrum (CI) m/z 417 ([M–THP], 100%),
219 (18), 175 (25), 133 (20), 85 (65).
(ii) Using phase transfer catalysis. A solution of 40% (w/w)
aqueous sodium hydroxide (10 mL, 20 equiv.) was added to a mixture
of monobenzyl ether (8) (2.41 g, 8.48 mmol), the tosylate (9) (2.57 g,
10.17 mmol) and tetrabutylammonium hydrogen sulfate (288 mg, 0.85
mmol). The mixture was stirred vigorously for 3 days at 65°C, then was
cooled to room temperature. Dichloromethane (100 mL) was added and
the organic phase was washed with water (3×75 mL), brine (75 mL),
dried (Na2SO4) and filtered through a plug of silica gel using ethyl
acetate as eluent. After removing the solvent under reduced pressure,
the resultant yellow liquid was purified by flash chromatography using
98:2 to 96:4 CH2Cl2/MeOH as eluent, to give the heptaethylene glycol
derivative (10) (2.90 g, 68%) as a yellow oil. The data acquired were
identical to those obtained for the preparation described above using
sodium hydride.
Phytanyl Tetraethylene Glycol Succinate (4)
A mixture of the hemisuccinate (3) (190 mg, 0.48 mmol), tetraethylene
glycol (463 mg, 2.4 mmol), DCC (120 mg, 0.58 mmol), DMAP (19 mg,
0.16 mmol) and DMAP·HCl (25 mg, 0.16 mmol) in dichloromethane (2
mL) was stirred for 70 h at room temperature. The suspension was
filtered through Celite®, the precipitate was washed with
dichloromethane, and the combined filtrates were concentrated to
dryness under reduced pressure. The resulting pale yellow oil was
chromatographed using ethyl acetate as eluent and provided the ester
(4) (186 mg, 68%) as a colourless viscous oil (Found: [M+H]+
575.4504. C32H62O8 requires [M+H]+ 575.4523). IR νmax 3500–2500,
1734 cm–1. 1H NMR δ 0.84–0.95, m, 15H, phytanyl CH3s; 0.90–1.75,
m, 24H, phytanyl CHs and CH2s; 2.63, m, 4H, succinyl CH2s;
3.55–3.75, m, 14H, OCH2CH2O; 4.09, m, 2H, CH(Me)CH2CH2O;
4.28, m, 2H, OCH2CH2OC(O). 13C NMR δ 19.4–19.7, overlapping
signals, non-terminal CH3s; 22.6, CH3; 22.7, CH3; 24.2, CH2; 24.4,
CH2; 24.7, CH2; 27.9, CH; 29.0, succinyl CH2; 29.05, succinyl CH2;
29.8, CH; 32.7, CH; 35.4, CH2; 35.5, CH2; 37.2, CH2; 37.3, CH2; 39.3,
CH2; 61.5, CH2; 61.7, CH2; 63.4, CH2; 63.7, CH2; 69.0, CH2; 70.3,
CH2; 70.5, CH2; 72.5, CH2; 172.3, C(O). Mass spectrum (EI) m/z 575
(2%), 425 (15), 399 (12), 277 (33), 195 (10), 189 (15), 145 (100).
Phytanyl Hexaethylene Glycol Succinate (5)
Hexaethylene glycol (2.91 g, 10.3 mmol), morpho-CDI (1.07 g, 2.5
mmol), DMAP (86 mg, 0.7 mmol) and DMAP·HCl (112 mg, 0.7 mmol)
were dissolved in anhydrous dichloromethane (9 mL) at room
temperature. Phytanyl hemisuccinate (3) (0.840 g, 2.1 mmol) was added

Components for Tethered Bilayer Membranes
435
Monobenzyl Heptaethylene Glycol (11)
filtrates were evaporated and the residue was chromatographed (ethyl
acetate/light petroleum, 1:1) to give the succinate (13) (980 mg, 80%)
(Found: C, 69.2; H, 11.4. C33H64O7 requires C, 69.2; H, 11.3%). IR νmax
(CHCl3) 1731 cm–1. 1H NMR δ 0.81–0.91, m, 15H, phytanyl CH3s;
1.0–1.7, m, 24H, phytanyl CHs and CH2s; 1.79–1.91, m, 6H,
CH2CH2CH2; 2.61, s, 4H, succinyl CH2s; 3.44–3.54, m, 4H, CH2O;
3.61, t, 2H, CH2O; 3.76, t, 2H, CH2O; 4.11, t, 2H, CH2OC(O); 4.17, t,
10 M HCl (0.05 mL) was added to a stirred solution of the
heptaethylene glycol derivative (10) (500 mg, 1.0 mmol) in a 1:1
mixture of CH2Cl2/MeOH (5 mL) at room temperature. After 6 h the
solvent was removed under reduced pressure. The crude material was
dissolved in ethyl acetate and the solution was filtered through Celite®.
The solvent was removed under vacuum to give the monoprotected diol
(11) as a pale yellow oil (416 mg, 100%) (Found: C, 57.7; H, 8.4.
C21H36O8·1¼H2O requires C, 57.5; H, 8.8%). IR νmax 3600–3200 cm–1.
1H NMR δ 2.10 (br) s, 1H, OH; 3.57–3.72, m, 28H, OCH2CH2O; 4.56,
s, 2H, CH2Ar; 7.29–7.35, m, 5H, ArH. 13C NMR δ 61.6, CH2; 69.4,
CH2; 70.2, CH2; 70.5, CH2; 72.6, CH2; 73.2, CH2; 127.6, Ar; 127.7, Ar;
128.3, Ar; 138.2, Ar quat. Mass spectrum (CI) m/z 417 ([M+H]+,
100%), 327 (14), 219 (11), 175 (13), 133 (11), 91 (11).
2H, CH2OC(O). 13C NMR
δ 19.4–19.7, overlapping signals,
non-terminal CH3s; 22.6, CH3; 22.7, CH3; 24.3, CH2; 24.5, CH2; 24.8,
CH2; 28.0, CH; 29.0, CH2; 29.2, CH2; 29.9, CH; 30.0, CH2; 32.0, CH2;
32.8, CH; 35.4, CH2; 35.5, CH2; 37.2–37.4, overlapping signals, CH2;
39.4, CH2; 61.9–62.2, overlapping signals, CH2; 67.2, CH2; 67.8, CH2;
68.2, CH2; 70.4, CH2; 172.3, C(O). Mass spectrum (CI) m/z 573
([M+H]+, 100%).
(Diphytanyl)glyceryl Hemisuccinate (15)
Phytanyl 1-Benzyl Heptaethylene Glycol Succinate (6)
Glycerol diphytanyl ether (14) (2.0 g, 3.06 mmol)[16] and succinic
anhydride (0.919 g, 9.19 mmol) were stirred in dry pyridine (6 mL) for
3 days at room temperature. The mixture was diluted with chloroform
(40 mL), and the solution was washed with water (2×25 mL). The
combined organic layers were dried (Na2SO4), filtered and the solvent
was removed at high vacuum. The hemisuccinate (15) was obtained as
a colourless oil (2.2 g, 97%) (Found [M+H]+, 753.6997. C47H92O6
requires [M+H]+, 753.6972). IR νmax 2923, 2867, 1744, 1715 cm–1. 1H
NMR δ 0.73–0.93, m, 30H, phytanyl CH3s; 0.93–1.74, m, 48H,
phytanyl CHs and CH2s; 2.67, br s, 4H, succinyl CH2s; 3.41–3.72, 7H,
m, CH2 and CHO; 4.06–4.30, 2H, m, CH2OC(O). 13C NMR δ 19.7, br
s, non-terminal CH3s; 22.6, CH3; 22.7, CH3; 24.4, CH2; 24.5, CH2;
24.8, CH2; 28.0, CH2; 28.8, succinyl CH2; 29.7–29.9, overlapping
signals, CH; 32.8, CH; 36.6, CH2; 36.7, CH2; 37.0, CH2; 37.1, CH2;
37.3–37.6, overlapping signals, CH2; 39.4, CH2; 64.4, CH2; 69.0, CH2;
70.1, CH2: 70.3, CH2; 76.5, CH; 172.0, C(O); 177.5, C(O). Mass
spectrum (ESI, negative ion) m/z 1505.3 (2M, 100%); 752.8 (M). This
compound hydrolysed readily and was converted immediately into the
succinate (16).
DMAP (11 mg, 0.09 mmol) was added to a solution of benzyl-protected
heptaethylene glycol (11) (151 mg, 0.36 mmol), the hemisuccinate (3)
(105 mg, 0.26 mmol) and morpho-CDI (134 mg, 0.32 mmol) in
dichloromethane (10 mL). The mixture was stirred at room temperature
for 16 h, and then was filtered through Celite®. The solvent was
removed under reduced pressure and the residue was dissolved in ethyl
acetate (75 mL). The organic phase was washed with water (50 mL),
brine (50 mL), dried (Na2SO4) and the solvent was removed under
vacuum to give the crude product as a pale yellow oil. Purification by
chromatography using ethyl acetate as eluent provided the succinic acid
diester (6) (76 mg, 36%) as a colourless oil (Found: C, 67.5; H, 10.4.
C45H80O11 requires C, 67.8; H, 10.1%). IR νmax 1738 cm–1. 1H NMR δ
0.81–0.90, m, 15H, phytanyl CH3s; 1.01–1.67, m, 24H, phytanyl CHs
and CH2s; 2.59–2.67, m, 4H, succinyl CH2s; 3.62–3.70, m, 26H,
OCH2CH2O; 4.09–4.13, m, 2H, CH2OH; 4.24, br t, J 4.9 Hz, 2H,
CH2OCH2Ph; 4.56, s, 2H, CH2Ph; 7.28–7.34, m, 5H, ArH. 13C NMR δ
19.44–19.74, overlapping signals, non-terminal CH3s; 22.6, CH3; 22.7,
CH3; 24.3, CH2; 24.5, CH2; 24.8, CH2; 28.0, CH; 29.0, succinyl CH2;
29.1, succinyl CH2; 29.9, CH; 32.8, CH; 35.4, CH2; 35.5, CH2; 37.27,
CH2; 37.34, CH2; 37.4, CH2; 39.4, CH2; 63.4, CH2; 63.8, CH2; 69.1,
CH2; 69.4, CH2; 70.6, CH2; 73.2, CH2Ar; 127.6, Ar; 127.7, Ar; 128.3,
Ar; 138.3, Ar quat.; 172.3, C(O). Mass spectrum (MALDI) m/z 822
([M+H+Na]+, 100%).
(Diphytanyl)glyceryl Hexaethylene Glycol Succinate (16)
The hemisuccinate (15) (2.0 g, 2.66 mmol) and hexaethylene glycol
(3.75 g, 13.3 mmol) were dissolved in dry dichloromethane (10 mL).
Morpho-CDI (1.35 g, 3.2 mmol), DMAP (107 mg, 0.88 mmol) and
DMAP·HCl (141 mg, 0.88 mmol) were added and the solution was
stirred at room temperature for 3 days. The suspension was diluted with
dichloromethane (40 mL), washed with water (2×25 mL), dried
(Na2SO4) and the solvent was removed to give a colourless oil.
Chromatography with ethyl acetate as eluent gave the succinate (16) as
a colourless oil (1.97 g, 74%) (Found: C, 69.6; H, 11.6. C59H116O12
requires C, 69.6; H, 11.5%). IR νmax 3466, 2925, 2868, 1739 cm–1. 1H
NMR δ 0.73–0.93, 30H, m, phytanyl CH3s; 0.93–1.72, 48H, m,
phytanyl CHs and CH2s; 2.65, 4H, s, succinyl CH2s; 3.40–3.71, 29H,
m, OCH2CH2O and OCH2CH(CH2O); 4.07–4.32, 4H, m, CH2OC(O).
13C NMR δ 19.4–19.8, overlapping signals, non-terminal CH3s; 22.6,
CH3; 22.7, CH3; 24.3, CH2; 24.4, CH2; 24.7, CH2; 27.9, CH; 28.9,
succinyl CH2; 29.6–29.8, overlapping signals, CH; 32.7, CH; 36.5,
CH2; 36.6, CH2; 36.9–37.4, overlapping signals, CH2; 39.3, CH2; 61.6,
CH2; 63.8, CH2; 64.3, CH2; 69.0, CH2; 70.0–70.5, overlapping signals,
CH2; 72.6, CH2; 76.4, CH; 172.1, C(O); 172.2, C(O). Mass spectrum
(FAB) m/z 1040 ([M+H+Na]+, 100%), 780 (10).
Phytanyl Heptaethylene Glycol Succinate (7)
A catalytic amount of 10% Pd/C was added to a solution of the benzyl
ether (6) (856 mg, 1.07 mmol) in ethanol (25 mL), and the mixture
stirred under an atmosphere of hydrogen for 60 h. The solution was
filtered through Celite® and the filtrate was concentrated under reduced
pressure to give the succinate (7) (759 mg, 100%) as a colourless oil.
An analytically pure sample was obtained by HPLC purification
(Whatman Partisil 10 column, 13.5 mL/min flow rate) using
dichloromethane/methanol (97:3) as eluent (Found: C, 64.0; H, 10.6.
C38H74O11·1/3H2O requires C, 64.0; H, 10.6%). IR νmax 3600–3300,
1738 cm–1. 1H NMR δ 0.81–0.89, m, 15H, phytanyl CH3s; 1.06–1.68,
m, 24H, phytanyl CHs and CH2s; 2.63, br t, J 3.6 Hz, 4H, succinyl
CH2s; 3.10, br s, 1H, OH; 3.57–3.74, m, 26H, OCH2CH2O; 4.10, br t, J
6.8 Hz, 2H, CH2OH; 4.21–4.26, m, 2H, CH(Me)CH2CH2O. 13C NMR
δ 19.39–19.70, overlapping signals, non-terminal CH3s; 22.6, CH3;
22.7, CH3; 24.3, CH2; 24.4, CH2; 24.8, CH2; 27.9, CH; 28.96, succinyl
CH2; 29.02, succinyl CH2; 29.8, CH; 32.7, CH; 37.2, CH2; 37.3, CH2;
39.3, CH2; 61.6, CH2OH; 63.3, CH2; 63.8, CH2; 69.0, CH2; 70.2, CH2;
70.5, CH2; 72.5, CH2; 172.3, C(O). Mass spectrum (CI) m/z 708
([M+H]+, 14%), 487 (27), 425 (23), 327 (75), 133 (73), 89 (100).
(Phytanol Tetraethylene Glycol Succinate) Hemisuccinate (17)
Succinic anhydride (1.7 g, 16.7 mmol) was added portionwise to a
solution of alcohol (4) (3.2 g, 5.6 mmol) in pyridine (20 mL), and the
mixture was stirred at room temperature for 3 days. Chilled 2 M HCl
(150 mL) was added and the aqueous solution was extracted with
dichloromethane (3×300 mL). The combined organic extracts were
washed with 1M HCl (300 mL), water (300 mL) and dried (Na2SO4),
and the solvent was removed under reduced pressure. Purification by
chromatography using 1:1 ethyl acetate/hexane to ethyl acetate to 95:5
ethyl acetate/ethanol as eluent provided the acid (17) (3.1 g, 83%) as a
pale yellow oil (Found: C, 64.0; H, 9.7. C36H66O11 requires C, 64.1; H,
Phytanyl Tripropylene Glycol Succinate (13)
To a solution of tripropyleneglycol[21] (12) (2.05 g, 10.6 mmol) and
phytanyl hemisuccinate (3) (850 mg, 2.1 mmol) in dry dichloromethane
(10 mL), was added morpho-CDI (1.08 g, 2.5 mmol), DMAP·HCl (113
mg, 0.71 mmol) and DMAP (86 mg, 0.71 mmol), and the mixture was
stirred at room temperature for 48 h. The suspension was filtered and
the residue was washed with dichloromethane (50 mL). The combined

436
C. J. Burns et al.
9.9%). IR νmax 3500–2500, 1734 cm–1. 1H NMR δ 0.83–0.90, m, 15H,
phytanyl CH3s; 1.03–1.68, m, 24H, phytanyl CHs and CH2s; 2.62–2.67,
m, 8H, succinyl CH2s; 3.63–3.71, m, 12H, OCH2CH2O; 4.07–4.14, m,
2H, CH(Me)CH2CH2O; 4.23–4.27, m, 4H, CH2OC(O). 13C NMR δ
19.4–19.7, m, non-terminal CH3s; 22.6, CH3; 22.7, CH3; 24.3, CH2;
24.5, CH2; 24.8, CH2; 28.0, CH; 29.0–29.3, m, CH2s; 29.8, CH; 32.8,
CH; 35.4, CH2; 35.5, CH2; 37.3, CH2; 37.4, CH2; 39.3, CH2; 63.4, CH2;
63.7, CH2; 63.8, CH2; 69.0, CH2; 70.5, CH2; 70.7, CH2; 172.0, C(O);
172.4, C(O); 175.6, C(O)OH. Mass spectrum (MALDI) m/z 697
([M+Na]+, 100%).
((Diphytanyl)glyceryl Hexaethylene Glycol Succinate) Hemisuccinate
(21)
Compound (16) (1.83 g, 1.80 mmol) and succinic anhydride (504 mg,
5.40 mmol) were stirred in dry pyridine (4 mL) under nitrogen at room
temperature for 3 days. The mixture was diluted with chloroform (50
mL) and washed with water (4×25 mL), dried (Na2SO4), filtered and
the solvent removed. The residue was chromatographed using ethyl
acetate/hexane (50:50 to 100:0) to give the title compound (1.62 g,
81%) as a colourless oil (Found [M+Na]+, 1139.8509, C63H120O15
requires [M+Na]+, 1139.8525). 1H NMR δ 0.75–0.92, m, 30H,
phytanyl CH3s; 0.92–1.72, m, 48H, phytanyl CHs and CH2s; 2.65,
broad s, 8H, succinyl CH2s; 3.40–3.72, m, 27H, CH2O and CHO;
4.06–4.32, m, 6H, CH2OCO. 13C NMR δ 19.5–19.8, overlapping
signals, non-terminal CH3s; 22.6, CH3; 22.7, CH3; 24.3, CH2; 24.4,
CH2; 24.7, CH2; 27.9, CH; 28.9, CH2; 29.7, CH2; 29.8, CH; 32.7, CH;
36.6, CH2; 36.7, CH2; 37.0, CH2; 37.1, CH2; 37.2–37.5, overlapping
signals, CH2; 39.3, CH2; 63.8, CH2; 64.3, CH2; 69.0, broad, CH2; 70.1,
CH2; 70.5, CH2; 70.7, CH2; 76.5, CH; 172.0–172.3, overlapping
signals, CO. Mass spectrum (ESI, positive ion) m/z 1139.6 ([M+Na]+,
100%), 1140.6 ([M+Na+H]+, 70%), 1117.6 ([M+H]+, 19%), 1155.4
([M+K]+, 18%).
(Phytanyl Hexaethylene Glycol Succinate) Hemisuccinate (18)
The hexaethylene glycol derivative (5) (0.80 g, 1.21 mmol) and succinic
anhydride (361 mg, 3.6 mmol) were stirred in dry pyridine (4.5 mL) at
room temperature under nitrogen for 45 h. The mixture was poured into
cold 2 M HCl (20 mL) and was extracted with dichloromethane (3×130
mL). The combined organic layers were washed with brine (150 mL),
dried (Na2SO4), filtered and the solvent was removed to give the acid
(18) (0.84 g, 91%) (Found: C, 62.4; H, 10.15. C40H74O13·½H2O
requires C, 62.2; H, 9.8%). IR νmax 3474, 2931, 1734 cm–1. 1H NMR δ
0.75–0.94, m, 15H, phytanyl CH3s; 0.94–1.75, m, 24H, phytanyl CHs
and CH2s; 2.62, m, 8H, succinyl CH2s; 3.55–3.75, m, 20H,
OCH2CH2O; 4.12, m, 2H, CH(Me)CH2CH2O; 4.25, m, 4H,
OCH2CH2OC(O).
Monophytanyl Triethylene Glycol (22)
A 60% dispersion of sodium hydride (1.56 g, 39.0 mmol) was added
portionwise to a solution of triethylene glycol (5.86 g, 39.0 mmol) in
THF (120 mL). The mixture was heated at reflux for 20 min, and was
allowed to cool to room temperature. A solution of phytanyl bromide[25]
(2.82 g, 7.80 mmol) in THF (5 mL) was added and the mixture heated
at reflux for 30 min, cooled to room temperature and water (10 mL) was
added. The solvent was removed under vacuum and the residue was
diluted with 3 M HCl (50 mL). The aqueous phase was extracted with
ethyl acetate (3×40 mL), and the combined organic extracts were
washed with water (50 mL), brine (50 mL), and dried (Na2SO4). The
solvent was removed under reduced pressure to afford the crude product
as a dark brown oil. Purification by chromatography using ethyl acetate
as eluent afforded the alcohol (22) (1.9 g, 57%) as a colourless oil
(Found: C, 67.0; H, 11.8. C26H54O4 requires C, 67.3; H, 11.6%). IR νmax
3500–3200 cm–1. 1H NMR δ 0.80–0.89, m, 15H, phytanyl CH3s;
1.00–1.68, m, 24H, phytanyl CHs and CH2s; 2.39, br s, 1H, OH;
3.45–3.52, m, 2H, CH(Me)CH2CH2O; 3.57–3.75, m, 12H,
(Phytanyl Heptaethylene Glycol Succinate) Hemisuccinate (19)
Succinic anhydride (84 mg, 0.84 mmol) was added to a solution of
alcohol (7) (149 mg, 0.21 mmol) in pyridine (1 mL). The mixture was
stirred for 40 h at room temperature and 1M HCl (30 mL) was added.
The aqueous solution was extracted with dichloromethane (3×25 mL),
and the combined organic extracts were washed with water (2×50 mL)
and brine (50 mL), and dried (Na2SO4). The solvent was removed under
reduced pressure to afford the acid (19) (163 mg, 96%) as a colourless
viscous oil (Found: C, 62.1; H, 9.9. C42H78O14 requires C, 62.5; H,
9.7%). IR νmax 3500–2500, 1732 cm–1. 1H NMR δ 0.82–0.90, m, 15H,
phytanyl CH3s; 1.01–1.69, m, 24H, phytanyl CHs and CH2s; 2.62–2.67,
m, 8H, succinyl CH2s; 3.61–3.75, m, 24H, OCH2CH2O; 4.07–4.14, m,
2H, CH(Me)CH2CH2O; 4.22–4.29, m, 4H, OCH2CH2OCO. 13C NMR
δ 19.39–19.70, overlapping signals, non-terminal CH3s; 22.6, CH3;
22.7, CH3; 24.3, CH2; 24.4, CH2; 24.8, CH2; 27.9, CH; 28.96, succinyl
CH2; 29.01, succinyl CH2; 29.4, succinyl CH2; 29.8, CH; 32.7, CH;
35.35, CH2; 35.44, CH2; 37.2, CH2; 37.3, CH2; 39.3, CH2; 63.4, CH2;
63.8, CH2; 68.9, CH2; 69.0, CH2; 70.4, CH2; 70.6, CH2; 172.0, C(O);
172.4, C(O); 175.0, C(O)OH. Mass spectrum (MALDI) m/z 846
([M+K]+, 46%), 829 ([M+Na]+, 100).
OCH2CH2O. 13C NMR
δ
19.63–19.70, overlapping signals,
non-terminal CH3s; 22.6, CH3; 22.7, CH3; 24.3, CH2; 24.5, CH2; 24.8,
CH2; 28.0, CH; 29.9, CH; 32.8, CH; 36.5, CH2; 36.6, CH2;
37.25–37.48, overlapping signals, CH2s; 39.4, CH2; 61.8, CH2OH;
69.9, CH2; 70.0, CH2; 70.4, CH2; 70.6, CH2; 72.5, CH2CH2OH. Mass
spectrum (ESI, positive ion) m/z 884 ([2M+Na]+, 56%), 453
([M+Na]+, 65), 448 ([M+H2O]+, 100), 431 ([M+H]+, 30).
Phytanyl Tripropylene Glycol Bissuccinate (20)
A solution of phytanyl tripropylene glycol succinate (13) (350 mg, 0.61
mmol) and succinic anhydride (120 mg, 1.2 mmol) in pyridine (5 mL)
was stirred for 24 h at room temperature under nitrogen. The reaction
mixture was poured into 3 M sulfuric acid (50 mL), and the suspension
was extracted with chloroform (3×30 mL). The organic layer was
washed with water (3×30 mL), then dried (MgSO4) and evaporated.
Purification by chromatography using ethyl acetate/hexane (1:1) as
eluent provided the succinate (20) (340 mg, 82%) as a pale yellow oil
(Found [M+H]+, 673.4868. C37H68O10 requires [M+H]+, 673.4891;
Found [M+Na]+, 695.4715. C37H68O10 requires [M+Na]+, 695.4710).
IR νmax (CHCl3) 1731 cm–1. 1H NMR δ 0.7–0.9, m, 15H, phytanyl
CH3s; 0.9–1.7, m, 24H, phytanyl CHs and CH2s; 1.7–1.95, m, 6H,
CH2CH2CH2; 2.60, m, 8H, succinyl CH2s; 3.40–3.55, m, 8H, CH2O;
4.10–4.25, m, 6H, CH2OCO; 5.4, (br)s, 1H, COOH. 13C NMR δ
19.4–19.7, overlapping signals, non-terminal CH3s; 22.6, CH3; 22.7,
CH3; 24.3, CH2; 24.4, CH2; 24.7, CH2; 27.9, CH; 28.8–29.1,
overlapping signals, succinyl CH2s; 29.8, CH2; 32.7, CH; 35.4, CH2;
35.5, CH2; 37.2, CH2; 37.3, CH2; 39.3, CH2; 62.0, m, CH2; 63.4, CH2;
66.9–67.1, overlapping signals, CH2; 67.6–67.8, overlapping signals,
CH2; 172.4, overlapping signals, C(O); 176.2, COOH. Mass spectrum
(ESI, positive ion) m/z 695.3 ([M+Na]+, 100%), 673.4 ([M+H]+, 30).
Monophytanyl Tri(ethylene Glycol) Tosylate (23)
Triethylamine (3.74 g, 37.0 mmol) was added to a mixture of alcohol
(22) (3.19 g, 7.40 mmol) and p-toluenesulfonyl chloride (1.69 g, 8.88
mmol) in dichloromethane (20 mL), and the solution was stirred for 12
h at room temperature. Dichloromethane (40 mL) was added and the
organic layer was washed with 3 M HCl (50 mL), water (50 mL), brine
(50 mL) and dried (Na2SO4). After removal of the solvent under
reduced pressure, the crude product was obtained as a yellow oil.
Purification by chromatography using dichloromethane as eluent
afforded the tosylate (23) as a pale yellow viscous oil (4.05 g, 94%)
1
(Found: C, 67.9; H, 10.3. C33H60O6S requires C, 67.8; H, 10.3%). H
NMR δ 0.80–0.88, m, 15H, phytanyl CH3s; 1.00–1.65, m, 24H,
phytanyl CHs and CH2s; 2.44, s, 3H, ArCH3; 3.43–3.51, m, 2H,
CH(Me)CH2CH2O; 3.55–3.62, m, 8H, OCH2CH2O; 3.66–3.71, m, 2H,
CH2CH2OTs; 4.16, m, 2H, CH2OTs; 7.34 and 7.80, AA´XX´, 4H, ArH.
13C NMR δ 19.63–19.70, overlapping signals, non-terminal CH3s; 21.6,
ArCH3; 22.6, CH3; 22.7, CH3; 24.3, CH2; 24.5, CH2; 24.8, CH2; 28.0,
CH; 29.9, CH; 32.8, CH; 36.6, CH2; 36.7, CH2; 37.3, CH2; 37.38, CH2;
37.43, CH2; 37.5, CH2; 39.4, CH2; 68.7, CH2; 69.2, CH2; 69.9, CH2;
70.1, CH2; 70.5, CH2; 70.7, CH2; 70.8, CH2; 128.0, Ar; 129.8, Ar;

Components for Tethered Bilayer Membranes
437
132.9, Ar quat.; 144.7, Ar. Mass spectrum (ESI) m/z 1191 ([2M+Na]+,
CH; 29.9, CH; 32.8, CH; 36.6, CH2; 36.7, CH2; 37.3, CH2; 37.38, CH2;
37.43, CH2; 37.5, CH2; 39.4, CH2; 61.7, CH2; 69.9, CH2; 70.1, CH2;
70.3, CH2; 70.6, CH2; 72.6, CH2. Mass spectrum (ESI) m/z 778
([M+K]+, 12%), 762 ([M+Na]+, 100), 759 (25).
25%), 608 ([M+Na]+, 91), 585 ([M+H]+, 100).
Monophytanyl Heptaethylene Glycol (24)
A 60% dispersion of sodium hydride (243 mg, 6.07 mmol) was added
to a solution of tetraethylene glycol (1.18 g, 6.07 mmol) in THF (25
mL). The mixture was heated at reflux for 10 min and cooled to room
temperature. A solution of the tosylate (23) (710 mg, 1.21 mmol) in
THF (25 mL) was added and the mixture heated at reflux for 30 min
The solvent was removed under vacuum and the reaction mixture was
quenched with saturated aqueous NH4Cl (5 mL) and diluted with water
(30 mL). The aqueous phase was extracted with dichloromethane (3×25
mL) and the combined organic extracts were washed with brine (50
mL), dried (Na2SO4) and the solvent was removed under reduced
pressure to afford the crude product as a dark yellow oil. Purification by
chromatography using 9:1 ethyl acetate/MeOH as eluent gave the
alcohol (24) as a pale yellow oil (611 mg, 83%) (Found: C, 67.0; H,
11.8. C34H70O8 requires C, 67.3; H, 11.6%). IR νmax 3600–3100 cm–1.
1H NMR δ 0.81–0.87, m, 15H, phytanyl CH3s; 1.06–1.64, m, 24H,
phytanyl CHs and CH2s; 2.73, br s, 1H, OH; 3.43–3.51, m, 2H,
CH(Me)CH2CH2O; 3.56–3.74, m, 28H, OCH2CH2O. 13C NMR δ
19.71, br s, non-terminal CH3s; 22.6, CH3; 22.7, CH3; 24.4, CH2; 24.5,
CH2; 24.8, CH2; 28.0, CH; 29.9, CH; 32.8, CH; 36.6, CH2; 36.7, CH2;
37.29–37.53, overlapping signals, CH2s; 39.4, CH2; 61.8, CH2OH;
69.9, CH2; 70.1, CH2; 70.4, CH2; 70.6, CH2; 72.6, CH2CH2OH. Mass
spectrum (ESI) m/z 631 ([M+H+Na]+, 38%), 630 ([M+Na]+, 100).
Monophytanyl Undecaethylene Glycol (27)
To a stirred solution of tetraethylene glycol (6.7 g, 34 mmol) in THF (50
mL) was added sodium (0.53 g) in small pieces, and the mixture was
stirred until all the sodium had been consumed. A solution of the
tosylate (25) (3.5 g, 4.6 mmol) in THF (25 mL) was added and the
mixture was heated at reflux for 90 min. Water (150 mL) was added to
the reaction mixture which was extracted with dichloromethane (1×100
mL, 1×60 mL). The combined organic layers were washed with water
(100 mL), brine (50 mL), and dried (Na2SO4). The solvent was removed
under reduced pressure to afford the crude product (27) as a pale yellow
oil (3.18 g, 88%) (Found: C, 64.6; H, 10.8. C42H86O12 requires C, 64.4;
H, 11.0%). 1H NMR δ 0.82–0.89, m, 15H, phytanyl CH3s; 1.0–1.7, m,
24H, phytanyl CHs and CH2s; 2.17, br s, 1H, OH; 3.47, m, 2H, and
3.59–3.80, m, 44H, CH2O. Mass spectrum (ES) m/z 822 ([M+K]+,
17%), 806 ([M+Na+H]+, 100). The alcohol (27) was further
characterized as its tosylate (28). Thus a mixture of the alcohol (27)
(2.2 g, 2.8 mmol) and p-toluenesulfonyl chloride (1.07 g, 5.63 mmol)
in dry dichloromethane (7 mL) was stirred at room temperature under
nitrogen. Triethylamine (1.42 g, 14.1 mmol) was added and the solution
continued stirring for 24 h. The reaction mixture was diluted with
dichloromethane (80 mL), and the organic layer was washed with 3 M
HCl (50 mL), water (2×50 mL), and brine (50 mL). The solution was
dried (Na2SO4), and the solvent was removed under reduced pressure.
The residue was purified by chromatography (CH2Cl2/MeOH, 96:4) on
silica to afford the tosylate (28) (2.14 g, 81%) as a colourless oil
Monophytanyl Hepta(ethylene Glycol) Tosylate (25)
Triethylamine (2.34 g, 23.2 mmol) was added to a mixture of alcohol
(24) (2.81 g, 4.63 mmol) and p-toluenesulfonyl chloride (1.32 g, 6.94
mmol) in dichloromethane (20 mL) and the solution was stirred for 12
h at room temperature. Dichloromethane (40 mL) was added and the
organic layer was washed with 3 M HCl (50 mL), water (50 mL), brine
(50 mL) and dried (Na2SO4). After removal of the solvent under
reduced pressure, the crude product was obtained as a dark yellow oil.
Chromatography using ethyl acetate as eluent afforded the tosylate (25)
as a pale yellow viscous oil (3.25 g, 92%) (Found: C, 64.8; H, 9.8.
C41H76O10S requires C, 64.7; H, 10.1%). 1H NMR δ 0.82–0.88, m, 15H,
phytanyl CH3s; 1.00–1.64, m, 24H, phytanyl CHs and CH2s; 2.44, s,
3H, ArCH3; 3.44–3.51, m, 2H, CH(Me)CH2CH2O; 3.53–3.70, m, 26H,
OCH2CH2O; 4.13–4.18, m, 2H, CH2OTs; 7.33 and 7.80 (AA´XX´),
4H, ArH. 13C NMR δ 19.64–19.73, overlapping signals, non-terminal
CH3s; 21.6, ArCH3; 22.6, CH3; 22.7, CH3; 24.3, CH2; 24.5, CH2; 24.8,
CH2; 27.9, CH; 29.9, CH; 32.8, CH; 36.6, CH2; 36.7, CH2;
37.28–37.51, overlapping signals, CH2s; 39.4, CH2; 68.7, CH2; 69.2,
CH2; 69.9, CH2; 70.1, CH2; 70.57, CH2; 70.59, CH2; 70.8, CH2; 128.0,
Ar; 129.8, Ar; 133.1, Ar quat.; 144.7, Ar. Mass spectrum (ESI) m/z 785
([M+H+Na]+, 12%), 784 ([M+Na]+, 100).
1
(Found: C, 62.4; H, 10.0. C49H92O14S requires C, 62.8; H, 9.9%). H
NMR δ 0.82–0.89, m, 15H, phytanyl CH3s; 1.0–1.7, m, 24H, phytanyl
CHs and CH2s; 2.45, s, 3H, CH3Ar; 3.47, m, 2H, and 3.59–3.80, m,
44H, CH2O; 4.15, t, 3H, J 6.8Hz, CH2OTs; 7.32 and 7.77 (AA´XX´),
4H, ArH. m/z (ESI) 961 ([M+H+Na]+, 54%), 960 ([M+Na]+, 100).
N-Methylphytanamide (30)
Phytanoic acid (29)[22] (6.4 g, 20.5 mmol) was dissolved in thionyl
chloride (10 mL) and the mixture was heated under reflux for 1.5 h.
Excess thionyl chloride was removed by distillation and the product was
dried under reduced pressure for 1 h. The resultant pale yellow oil was
added dropwise into a solution of methylamine in tetrahydrofuran (2 M
solution in THF, 50 mL), and the mixture was stirred for 18 h. The
solution was concentrated under reduced pressure and the product
partitioned betweenwater (150mL) anddichloromethane (100 mL). The
organic layer was collected and was washed with 1 M HCl (2×50 mL),
then with brine (50 mL) and dried (MgSO4). The solvent was removed
and the crude product purified by chromatography (CH2Cl2/MeOH,
96:4–90:10) to give the amide (30) as a colourless oil (4.77 g, 70%)
(Found: C, 77.7; H, 13.5; N, 4.4. C21H43NO requires C, 77.5; H, 13.3; N,
4.3%). IR νmax 3292, 3092, 1644, 1556 cm–1. 1H NMR δ 0.81–1.64, m,
37H, phytanyl CHs, CH2s and CH3s; 1.93, m, and 2.19, m, 2H,
Monophytanyl Decaethylene Glycol (26)
A 60% dispersion of sodium hydride (166 mg, 4.16 mmol) was added
to a solution of triethylene glycol (625 mg, 4.16 mmol) in THF (30 mL).
The mixture was heated at reflux for 10 min and cooled to room
temperature. A solution of the tosylate (25) (633 mg, 0.83 mmol) in
THF (10 mL) was added, and the mixture heated at reflux for 20 min.
The solvent was removed under vacuum and the reaction mixture was
quenched with saturated aqueous NH4Cl (5 mL) and diluted further
with water (30 mL). The aqueous phase was extracted with
dichloromethane (3×25 mL), the combined organic extracts were
washed with brine (50 mL), dried (Na2SO4) and the solvent was
removed under reduced pressure to afford the crude product as a yellow
oil. Chromatography using 9:1 to 8:2 ethyl acetate/MeOH as eluent
afforded the decaethylene glycol derivative (26) as a pale yellow
viscous oil (536 mg, 87%) (Found: C, 64.0; H, 11.1. C40H82O11·½H2O
requires C, 64.2; H, 11.2%). IR νmax 3600–3200 cm–1. 1H NMR δ
0.80–0.90, m, 15H, phytanyl CH3s; 1.01–1.66, m, 24H, phytanyl CHs
and CH2s; 1.91, br s, 1H, OH; 3.44–3.51, m, 2H, CH(Me)CH2CH2O;
3.54–3.76, m, 40H, OCH2CH2O. 13C NMR δ 19.68, br s, non-terminal
CH3s; 22.6, CH3; 22.7, CH3; 24.3, CH2; 24.5, CH2; 24.8, CH2; 28.0,
CH2CONHCH3; 2.79 and 2.81, s, 3H, NCH3; 5.30, br s, 1H, NH. 13
C
NMR δ 19.6, non-terminal CH3s; 22.5, CH3; 22.6, CH3; 24.4, CH2; 24.7,
CH2;26.1, NCH3; 27.9, CH; 30.7, CH; 32.7, CH; 37.0–37.4, overlapping
signals, CH2; 39.3, CH2; 44.35, CH2; 44.42, CH2; 173.4, C(O). Mass
spectrum(CI)m/z 326(M+),270.
Methyl Phytanyl Amine (31)
A mixture of N-methylphytanamide (29) (4.0 g, 12.3 mmol) and lithium
aluminium hydride (pellets 95%, 2.0 g) in THF (100 mL) was heated
under reflux for 2 h. The reaction mixture was cooled, excess lithium
aluminium hydride was destroyed, and solid salts were filtered off. The
filtrate was evaporated, the residue was dissolved in dichloromethane
(100 mL) and the solution was washed with water (50 mL), dried
(MgSO4) and the solvent was removed. The crude product was chroma-
tographed (CH2Cl2/MeOH/aq-NH3, 90:10:1–80:20:1) to give methyl-
phytanylamine (31) (2.08 g, 54%) as a colourless oil (Found: C, 79.3;

438
C. J. Burns et al.
H, 14.5; N, 4.5. C21H45N·1/3H2O requires C, 79.4; H, 14.5; N, 4.4%). IR
Acknowledgments
1
νmax (film) 3392 cm–1. H NMR δ 0.82–1.5, m, 39H, phytanyl CHs,
CH2s and CH3s; 2.44, s, 3H, NCH3; 2.54, m, 2H, CH2NH. 13C NMR δ
19.7, non-terminal CH3s; 22.6, CH3; 22.7, CH3; 24.4, CH2; 24.5, CH2;
24.8, CH2; 28.0, CH; 31.0, CH; 32.8, CH; 36.2, NCH3; 36.8, overlap-
ping signals, CH2; 37.4, overlapping signals, CH2; 39.4, CH2; 49.9,
CH2N. Mass spectrum (ES) m/z 419 (M+, 100%).
We acknowledge financial support from the Australian
Government through the Cooperative Research Centre for
Molecular Engineering and Technology, and Pacific Dunlop
Ltd for the award of a Pacific Dunlop Scholarship (B.J.P.).
N-Methylphytanylamine Hemisuccinamide (32)
References
Methylphytanylamine (31) (1.0 g, 3.2 mmol) and succinic anhydride
(1.0 g, 10 mmol) were dissolved in pyridine (5 mL) and the solution was
stirred at room temperature for 18 h. The solvent was removed, and the
crude product was dissolved in dichloromethane (50 mL). The organic
solution was washed with 2 M HCl (20 mL), then with water (20 mL) and
finally dried (MgSO4). The crude product was obtained after removal of
the solvent and was chromatographed (CH2Cl2/MeOH, 98:2–95:5) to
give N-methylphytanylamine hemisuccinamide (32) (1.3 g, 100%) as a
colourless oil (Found [M+H]+, 412.3789. C25H49NO3 requires [M+H]+,
412.3790). IR νmax 3300–2500(br), 1746, 1716, 1634, 1597. 1H NMR δ
0.82–1.55, m, 39H, phytanyl CHs, CH2s and CH3s; 2.69, m, 4H, succinyl
CH2s; 2.95 and 3.01, s, 3H, NCH3; 3.25–3.5, m, 2H, CH2N. 13C NMR δ
19.4–19.7, overlapping signals, non-terminal CH3s; 22.6, CH3; 22.7,
CH3; 24.3, CH2; 24.4, CH2; 24.8, CH2; 27.9, CH; 28.6, CH2; 30.0–30.3,
overlapping signals, CH2; 30.8, CH; 32.7, CH; 33.8, NCH3; 34.1, CH2;
34.2, CH2; 35.2, NCH3; 37.4, overlapping signals, CH2; 39.3, CH2; 46.6,
CH2N; 48.4, CH2N; 171.9, C(O); 176.5, COOH. Mass spectrum (ESI,
negative ion) m/z 822 (dimer, 100%), 412 (1).
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N-Methylphytanamine (N-Methyl-N´-methyl-3,6,9-trioxa-
1,11-diaminoundecane) Succinamide (34)
N-Methylphytanylamine hemisuccinamide (32) (447 mg, 1.1 mmol), the
diamine (33)[23] (1.2 g, 5.5 mmol) and DCC (270 mg, 1.3 mmol) were
dissolved in dry dichloromethane (50 mL), and the mixture was stirred
for 96 h at room temperature under nitrogen. The white precipitate
formed was removed by filtration, and the crude product obtained from
the filtrate was chromatographed (CH2Cl2/MeOH, 85:5) to give the
succinamide (34) as a colourless oil (313 mg, 69%). 1H NMR δ
0.82–1.55, m, 39H, phytanyl CHs, CH2s and CH3s; 2.45, (br) s, NH;
2.64, m, 4H, succinyl CH2s; 2.76, m, 2H, CH2NH; 2.91, 2.96, 3.01, 3.11,
singlets, 6H, C(O)NCH3; 3.36, m, 2H, CH2NC(O); 3.59, m, 14H, CH2s.
This compound was used immediately in the next step.
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From reaction with succinic anhydride. The succinamide (34)
(461 mg, 0.75 mmol) and succinic anhydride (200 mg, 2 mmol) were
dissolved in pyridine (10 mL), and the solution was stirred at room
temperature for 48 h. The solvent was removed and the crude product
was purified by chromatography (CH2Cl2/MeOH/AcOH, 84:15:1 as
eluent) to give the acid (35) (530 mg, 100%) as a colourless oil (Found:
C, 62.8; H, 10.2; N, 5.7. C39H75N3O8·1½H2O requires C, 63.2; H, 10.6;
N, 5.7%). IR νmax (CHCl3) 1731, 1632 cm–1. 1H NMR δ 0.82–1.55, m,
39H, phytanyl CHs, CH2s and CH3s; 2.68, m, 8H, succinyl CH2s; 2.91,
2.96, 3.01, 3.09, 3.11, singlets, 9H, NCH3; 3.36, m, 2H,
CH(Me)CH2CH2N; 3.60, m, 16H, N(Me)CH2CH2O and OCH2CH2O.
13C NMR (signals from the different conformational isomers are
recorded as observed) δ 19.4–19.7, overlapping signals, non-terminal
CH3s; 22.6, CH3; 22.7, CH3; 24.3, CH2; 24.4, CH2; 24.7, CH2; 27.9,
CH; 28.0, CH2; 28.4, CH2; 29.6, CH2; 29.8, CH2; 30.8, CH; 32.7, CH;
33.6, NCH3; 33.9, NCH3; 34.1, CH2; 34.3, NCH3; 35.1, NCH3; 35.3,
CH2; 36.8, NCH3; 36.9, NCH3; 37.3, overlapping signals, CH2; 39.3,
CH2; 46.3, CH2N; 47.8, CH2N; 48.0, CH2N; 48.3, CH2N; 49.4, CH2N;
49.8, CH2N; 68.4, CH2; 69.1, overlapping signals, CH2; 70.2–71.0,
overlapping signals, CH2; 171.9–172.7, overlapping signals, C(O);
175.0, COOH. Mass spectrum (MALDI) m/z 715, 714; (ESI) m/z 736.4
([M+Na]+, 100%).
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