The mixture was stirred for 30 min at room temperature, then
triethylsilane (15 drops) was added drop wise. After stirring for
another 15 min, cold water (10 mL) was added and the reaction
mixture was extracted with dichloromethane (3 ¥ 15 mL). The
combined organic phases were dried over Na2SO4, filtered and
the solvent was removed. The crude product was purified by
column chromatography (silica, hexane–ethyl acetate gradient of
pure hexane to 2:1) under nitrogen flow to yield 21 mg (85%) of
the yellow product.
1H NMR (CDCl3, 400 MHz): d 7.94 (dt, 2H, J = 9.0 Hz), 7.83
(dt, 2H, J = 8.4), 7.69 (d, 2H, J = 1.7), 7.33 (t, 1H, J = 1.7),
7.29 (dt, 2H, J = 8.3), 6.99 (dt, 2H, J = 9.0), 4.34 (t, 2H), 4.07
(t, 2H), 3.52 (s, 2H), 2.66 (t, 2H), 1.93–1.82 (m, 6H), 1.68–1.60
(m, 4H), 1.31–1.25 (m, 12H), 0.87 (t, 3H). 13C NMR (CDCl3,
100 MHz): d 123.3, 152.1, 148.3, 147.8, 134.6, 14.5, 133.54, 130.7,
128.9, 126.6, 124.2, 116.4, 69.6, 66.9, 37.5, 33.6, 33.0, 31.3, 31.2,
31.1, 31.0, 30.9, 30.5, 30.1, 24.33, 24.3, 15.8. Exact mass calculated:
593.2866, found: 593.2851 [M + H+].
11 mmol) in 20 mL acetone were refluxed for 45 h. The solvent
was removed and after addition of water (40 mL) the mixture
was extracted with dichloromethane (4 ¥ 30 mL). The combined
organic phases were dried over MgSO4, filtered and the solvent
was removed to yield an off-white solid. Recrystallisation from
a mixture of chloroform and hexane gave 5.0 g (93%) of pure
product.
1H NMR (CDCl3, 400 MHz): d 6.11 (dd, 2H), 3.74 (t, 2H, J =
6.8 Hz), 3.39 (t, 2H, J = 6.8), 3.37 (m, 2H), 3.26 (m, 2H), 1.73 (m,
1H), 1.53 (d, 1H). 13C NMR (CD3OD, 100 MHz): d 179.6, 137.0,
54.6, 48.2, 47.4, 42.1, 29.3.
Poly-N -(2-bromoethyl)-4-vinyltetrahydrocyclopenta[c]pyrrole-
1,3(2H,3aH)-dione. Under
a
nitrogen atmosphere, N-2-
bromoethyl-cis-5-norbornene-2,3-dicarboxylic imide (110 mg,
0.4 mmol) was dissolved in 10 mL freshly distilled and degassed
THF. A solution of 2nd generation Grubbs catalyst (6.95 mg,
0.008 mmol) in THF (2 mL) was added via a syringe. The resulting
purple solution was refluxed for 2.5 h. During this time the solution
turned cloudy yellow. Ethyl vinyl ether (1 mL) was added and the
mixture was refluxed for another 15 min. The solvent was removed
and chloroform was added to dissolve the residue, followed by
methanol to precipitate the product which was filtered, washed
with methanol and dried to yield 111 mg (100%) of product.
1H NMR (CDCl3, 400 MHz): d 7.33–7.30 (m, 5H), 5.66–5.60
(m, br, ~164H), 3.82 (m, br, ~162H), 3.54 (m, br, ~162H), 3.17–
2.88 (m, br, ~324H), 1.90–1.80 (m, br, ~81H), 1.57–1.40 (m, br,
~81H). GPC (THF, flow rate 1 mL/min): Mn = 21 985, Mw = 23
050, PDI = 1.05.
Polymeric guest (3). Under a nitrogen atmosphere, the bro-
mide polymer (100 mg) and isoquinoline (0.5 mL) were refluxed in
3 mL chloroform for 4 days. Then diethyl ether (20 mL) was added
and the solution was sonicated for a few minutes. The resulting
solid was filtered and dried to yield 135 mg of a brown-yellow
product.
1H NMR (D2O, 400 MHz): d 9.78 (s, br), 8.64–7.77 (m, br), 4.97
(s, br), 4.21 (s, br), 3.23 (s, br), 2.44 (s, br), 1.47 (s, br), 0.75 (s, br).
Elemental analysis calculated: C 59.56%, H 5.75%, N 6.95%, Br
19.81%, found: C 57.88%, H 4.75%, N 6.13%, Br 18.35%.
Amphiphilic receptor (1a). A mixture of 5-(4-((4-decylphenyl)-
diazenyl)phenoxy)pentyl-3,5-dimercaptobenzoate
(220
mg,
0.37 mmol) and 2,6-dimercapto-9,10-dihydro-9,10-etheno-
anthracene-11,12-dicarboxylic acid7 (265 mg, 0.74 mmol) was
stirred at room temperature in a mixture of DMSO (45 mL) and
THF (75 mL) for 45 h. THF was removed under reduced pressure
and water (200 mL) was added, followed by 3 N HCl to acidify
the solution which was then extracted with dichloromethane
(4 ¥ 60 mL). The combined organic phases were washed with
dilute HCl (0.01 N), dried over Na2SO4 and filtered. The solvent
was removed and the crude product was purified by column
chromatography (silica, dichloromethane–methanol (both with
0.05% formic acid) gradient from 10:1 to 1:1) which yielded
179 mg (37%) of the product as a mixture of isomers.
Characterisation of the major isomer: 1H NMR (CD3OD–
CDCl3 ª 1:5 v/v, 400 MHz): d 8.06 (d, 1H, J = 1.6 Hz), 7.97
(d, 1H, J = 1.6), 7.85 (d, 2H, J = 8.8), 7.75 (d, 1H), 7.59 (br,
1H), 7.48–7.42 (m, 4H), 7.27 (d, 2H), 7.20–7.04 (m, 8H), 6.98 (d,
2H, J = 8.8), 5.77 (s, 1H), 5.75 (br s, 3H), 4.35 (m, 2H), 4.08 (m,
2H), 2.64 (t, 2H), 1.93–1.80 (m, 4H), 1.60–1.57 (m, 6H), 1.29–
1.22 (m, 12H), 0.84 (t, 3H). 13C NMR (CD3OD–CDCl3 ª 1:5
v/v, 125 MHz): d 166.6, 166.5, 150.7, 149.3, 149.2, 145.8, 145.3,
141.7, 138.4, 133.3, 128.9, 124.6, 124.4, 124.3, 122.3, 122.2, 114.5,
67.8, 65.2, 52.6, 52.4, 35.6, 31.7, 31.1, 29.4, 29.4, 29.3, 29.2, 29.2,
29.1, 29.0, 28.6, 28.3, 22.4, 13.8. Exact mass calculated: 1299.2751,
found: 1299.2795 [M + H+].
Preparation of LUVs
A solution of 25 mg of egg PC in 1 mL chloroform (purchased from
Avanti Polar Lipids, Inc.) was placed in a test tube. If appropriate,
1a (2.1 mg, 5 mol%) was added followed by 0.2 mL methanol to
aid dissolution. The solvent was evaporated under a stream of
nitrogen to leave a lipid film that was dried under vacuum over
night.
Then 10 mM phosphate buffer pH 8 (3.29 mL) was added and
the solution was vortexed for 30 s, incubated for 5 min and vortexed
again for 30 s. After incubating for 20 min, 5 freeze–thaw cycles
were performed, followed by extrusion, first 10 times through a
polycarbonate membrane with a 400 nm pore size and finally
10 times through one with a 200 nm pore size.
cis-5-Norbornene-2,3-dicarboxylic imide. A mixture of cis-5-
norbornene-endo-2,3-dicarboxylic anhydride (8.2 g, 50 mmol) and
urea (6 g, 100 mmol) was heated at 145 ◦C for 4 h. Water (50 mL)
was added and the solution was heated until it was homogenous. A
white-grey solid precipitated upon cooling. It was filtered, washed
with cold water and dried to yield 7.2 g (91%) of imide.
1H NMR (CDCl3, 400 MHz): d 8.20 (br, 1H), 6.18 (dd, 2H),
3.36 (m, 2H), 3.29 (m, 2H), 1.72 (d, 1H, J = 8.8 Hz), 1.50 (d, J =
8.8, 1H). 13C NMR (CD3OD, 100 MHz): d 180.5, 137.1, 54.7, 49.8,
47.4. Exact mass calculated: 164.0706, found: 164.0712 [M + H+].
Gel filtration
N-(2-Bromoethyl)-cis-5-norbornene-2,3-dicarboxylic
cis-5-Norbornene-2,3-dicarboxylic imide (3.26 g, 20 mmol),
1,2-dibromoethane (10 mL, 116 mmol) and K2CO3 (1.51 g,
imide.
A pre-packed Sephadex G-25 M column (Amersham Biosciences)
was saturated with lipids, then freshly prepared 5 mM egg PC
vesicles containing 5 mol% 1a (2.5 mL) were added to the column,
This journal is
The Royal Society of Chemistry 2009
Org. Biomol. Chem., 2009, 7, 4289–4295 | 4293
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