1
copper(I) iodide, ethyl 3-iodobenzoate (Tokyo Kasei), 1-
aminopyrene (Tokyo Kasei), N,N¤-dicyclohexylcarbodiimide
(DCC, Tokyo Kasei), N-(4-pyridyl)dimethylamine (DMAP,
Wako Pure Chemical), (bicyclo[2.2.1]hepta-2,5-diene)chloro-
rhodium(I) dimer ([Rh(nbd)Cl]2, Aldrich), chloro(1,5-cyclo-
octadiene)rhodium(I) dimer ([Rh(cod)Cl]2, Aldrich), and 2,5-
norbornadiene (Tokyo Kasei) were all purchased and used
without further purification. The solvents were treated as
follows: tetrahydrofuran (THF) was dried over calcium
hydride, triethylamine (Et3N) over potassium hydride, and
chloroform under nitrogen. Other chemicals were obtained
from Kanto Kagaku Co. and were used as received.
(C¸C), 3200 (C¸CH), 3400 (-COOH). H NMR (400 MHz,
DMSO-d6, ppm): ¤ 4.5 (s, C¸CH, 1H), 7.6, 8.0 (d, Ar-H, 4H),
13.1 (s, -COOH, 1H). 13C NMR (100 MHz, CDCl3, ppm): ¤
82.2, 83.1, 126.8, 139.7, 131.1, 132.5, 167.0.
Synthesis of 4-Ethynyl-N-pyrenylbenzamide (EPBA) (2).
First, (0.217 g 1.0 mmol) of 4-ethynylbenzoic acid, (0.146 g,
1.0 mmol) of 1-aminopyrene, (0.040 g, 3.2 mmol) of DMAP,
and (0.068 g, 0.4 mmol) of p-toluenesulfonic acid monohydrate
were dissolved in 10 mL of dry dichloromethane. To the di-
chloromethane solution, 0.82 g (4 mmol) of DCC was added
dropwise with stirring. The reaction mixture was stirred for
24 h at room temperature. After the solvent was removed, the
crude product was washed with saturated sodium hydrogen
carbonate aqueous solution, 0.1 M HCl aqueous solution, and
water. The organic phase was dried over Na2SO4 and con-
centrated by rotary evaporation. The residue was purified
by recrystallization from MeOH and acetone to afford solid
EPBA 2 in 85% yield. The data are as follows. Yield: 85.0,
brown powder (Figure 1). IR (cm¹1, KBr): 650 (C¸CH), 1750
(C=O), 2200 (C¸C), 3200 (C¸CH), 3300 (-NH). 1H NMR
(400 MHz, CDCl3, ppm): ¤ 3.0 (s, C¸CH, 1H), 4.5 (s, -NH
1H), 7.6, 7.8 (d, Ar-H, 4H), 8.0-8.5 (m, 9H). 13C NMR
(100 MHz, CDCl3, ppm): ¤ 51.2, 82.2, 83.1, 126.8, 125-135
(Pyrene), 139.7, 131.1, 132.5, 180.0.
Monomer and Catalyst Synthesis.
Synthesis of 4-
Ethynylbenzoic Acid (1): The reaction procedures are similar
to these reported elsewhere.28 To a 200-mL three-necked flask
were added methyl ethyl-4-iodebenzoate (5.0 g, 25.7 mmol),
2-methyl-3-butyn-2-ol (2.51 mL, 25.7 mmol), Ph3P (0.075 g,
0.28 mmol), CuI (23 mg, 0.12 mmol) in 93.2 mL of dry Et3N
and 7 mL of dry pyridine. [PdCl2(Ph3P)2] (326 mg, 3.8 mmol)
was then added to the above mixture under nitrogen. After
refluxing for 4 h at ca. 80 °C, the mixture was cooled to room
temperature and filtered to remove the insoluble trimethylamine
hydrobromide. The salt was washed with trimethylamine and
ethyl ether until the ether washings were clear. The combined
filtrates were reduced to dryness under reduced pressure, and
the crude product was washed with water. The residue was
dried under vacuum to yield 3.12 g of methyl 4-(3-hydroxy-3-
methylbut-1-ynyl)benzoate. The above solid was dissolved in
300 mL of refluxing solution of n-butanol with 3.2 g of KOH.
After refluxing for 10 min, the mixture was cooled in an ice
bath. After filtration, the collected residue was acidified to pH 2
by HCl. The mixture was extracted with ethyl acetate. After
removing the solvent, the residue was dried under vacuum to
yield 2.31 g of 4-ethynylbenzoic acid 1 as a yellow solid (yield
76.2%) (Figure 1). IR (KBr): 650 (C¸CH), 1750 (C=O), 2200
Synthesis of [Rh(nbd){B(C6H5)4}] Catalyst. Synthesis of
this catalyst was carried out according to the method reported
by Schrock et al.29 RhCl3¢3H2O (250 mg) was dissolved in
water (1 mL), and Na[B(C6H5)4] (1 g) in methanol (20 mL) was
added. 2,5-Norbornadiene (nbd; 1 mL) was then added and the
solution was allowed to stand until crystals were deposited.
The yellow crystalline product was filtered and air-dried. The
desired complex was obtained in a yield of ca. 68.2%.
Polymer Synthesis (3).
All the polymerizations were
carried out in a glass tube equipped with a three way stopcock
under nitrogen. The polymerization conditions were as follows:
Synthesis of EA
O
O
O
[Pd], CuI
TEA, THF
O
+
HO
I
HO
O
KOH
BuOH
OH
ꢀ
Synthesis of PEBA
NH2
O
O
DCC, DMAP
TsOH, CHCl3
N
+
OH
H
ꢁ
Figure 1. The synthetic route of 4-ethynylbenzoic acid (1) and 4-ethynyl-N-pyrenylbenzamide (EPBA) (2).
© 2016 The Chemical Society of Japan