Synthesis of 4-(2-arylvinyl)-8-hydroxyquinolines via anhydrous Heck coupling reaction and the PL properties of their Al complexes

Article abstract of DOI:10.1016/j.tet.2009.03.028

Anhydrous Heck coupling between 2 and eight different arylvinyl compounds using 3 mol % of PdCl₂/2PPh₃ catalyst system occurs selectively at position-4 of 2 affording 4-(2-arylvinyl)-8-tosyloxyquinolines 3 in good to high yields. The

Full text of DOI:10.1016/j.tet.2009.03.028

Tetrahedron 65 (2009) 4422–4428
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Synthesis of 4-(2-arylvinyl)-8-hydroxyquinolines via anhydrous Heck coupling
reaction and the PL properties of their Al complexes
*
Walaa A.E. Omar, Osmo E.O. Hormi
Department of Chemistry, University of Oulu, P.O. Box 3000, 90014 Oulu, Finland
a r t i c l e i n f o
a b s t r a c t
Article history:
Anhydrous Heck coupling between 2 and eight different arylvinyl compounds using 3 mol % of
PdCl2/2PPh3 catalyst system occurs selectively at position-4 of 2 affording 4-(2-arylvinyl)-8-tosyloxy-
quinolines 3 in good to high yields. The tosyloxy protecting group showed high stability under anhydrous
coupling conditions. Deprotection of the resulting 4-arylvinyl-8-tosyloxyquinolines produced 4-(2-ar-
ylvinyl)-8-hydroxyquinolines 4 in high yields. The aluminium complexes of the resulting 8-hydrox-
yquinolines have been synthesized and their photoluminescence (PL) properties have been studied. One
of the complexes with a 2,4,6-trimethoxystyryl substituent at position-4 of the quinolate shows higher
relative PL quantum yield than the other complexes due to the minimization of the cis–trans photo-
isomerization in solution.
Received 13 December 2008
Received in revised form 27 February 2009
Accepted 12 March 2009
Available online 20 March 2009
Ó 2009 Elsevier Ltd. All rights reserved.
1. Introduction
The Heck coupling reaction is one of the most important
reactions for C–C bond formation.17–32 The reaction is usually used
Arylvinylquinolines such as styrylquinolines and pyridyl-
vinylquinolines are important quinoline classes due to their bi-
ological potency as LTD4 receptor antagonists.1,2 2-Styrylquinolines
derivatives are also promising antiviral agents because they inhibit
HIV integrase (an enzyme that integrates genetic material from the
virus into target cell) both in vitro and in vivo and are devoid of
cellular toxicity.3–9 Both 4- and 2-(2-arylvinyl)-8-hydroxyquinoline
derivatives can also act as chelating agents, which co-ordinate with
divalent metal ions such as Zn(II) and Mg(II)9 and trivalent metal
ions such as Al(III)10,11 and can, therefore, be used for the production
of many important metal complexes.
to couple olefins to unsaturated halides or triflates. The coupling is
stereoselective giving the trans isomer predominantly. The wide
variety of palladium catalyst systems and the high stereoselectivity
of the resulting products in Heck coupling enable us to study it as
an alternative for the production of 4-(2-arylvinyl)quinolines.
Several protecting groups such as OMe, OTBS or OTDS have been
used to protect hydroxyl groups during a Heck coupling.28–32
Tosyloxy group has been used as a leaving group33 and it has not so
far been used as a protecting group for hydroxyls during Heck
coupling reactions of unsaturated halides and olefins.
In this work, we have used a commercially available PdCl2/2PPh3
2-Arylvinylquinolines are usually prepared by condensation
reactions between methylquinolines and suitable aromatic alde-
hydes. The condensation reactions may result in the formation of
mixture of isomers (E and Z) of the target 2-arylvinylquinoline and
the condensations are often accompanied by long reaction time and
low yields.1–15
catalyst system and 4-bromo-8-tosyloxyquinoline 2 as the
substrate in Heck couplings with arylvinyl compounds to produce
4-(2-arylvinyl)-8-tosyloxyquinolines 3 in good to high yields. The
tosyloxy protecting group was very stable under the coupling
conditions. Subsequent alkaline hydrolysis34,35 of the coupling
products 3 gave 4-(2-arylvinyl)-8-hydroxyquinoline derivatives 4
in high yields.
The aluminium complexes of the resulting 4-(2-arylvinyl)-8-
hydroxyquinolines (complexes 5) have also been synthesized and
their PL properties have been studied.
Aluminium and zinc metal complexes of 2-styryl-8-hydroxy-
quinolines with 4-methyl, 4-chloro and 4-methoxy substituents on
the styryl group are generally red shifted (lPL 513–576 nm) from the
parent aluminium tris(8-hydroxyquiniline) (Alq3, lPL¼509 nm),
they are significantly more thermally stable and more soluble in
common organic solvents than the parent Alq3 and zinc
Recently, Dabiri et al.16 have developed a one-pot synthesis of 2-
(2-arylvinyl)quinolines bearing different groups at position-3. They
used a Friedla¨nder reaction of a 2-aminoalkylketone and a methyl-
ketone followed by Knoevenagel condensation with an aromatic
aldehyde. The reactions were performed in the presence of 1-
methylimidazolium trifluoroacetate.
* Corresponding author. Tel.: þ358 8 553 1631; fax: þ358 8 553 1593.
E-mail address: osmo.hormi@oulu.fi (O.E.O. Hormi).
0040-4020/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2009.03.028

W.A.E. Omar, O.E.O. Hormi / Tetrahedron 65 (2009) 4422–4428
4423
bis(8-hydroxyquinoline) (Znq2). Moreover, the Al complexes
showed PL quantum yields ranging from 0.007 to 0.133 (the PL
quantum yield for Alq3 is 0.171).10 Compared with the unsub-
stituted Alq3, Al complexes with 2-arylvinyl substituents at posi-
tion-4 (complexes 5a–h) show large red shifts (56–88 nm) in the PL
emission and are less soluble in common organic solvents.
On the other hand, it has earlier been observed that metal
complexes of styryl-substituted ligands undergo cis–trans photo-
isomerization in fluids at room temperature. Such phenomena
cause a quenching for the PL emission. For example, cyclometalated
platinum complexes of phenylpyridine ligands bearing styryl
moieties at position-4 showed cis–trans photoisomerization in
solution under sunlight. The cis–trans photoisomerization caused
weak PL emission intensities and lower PL quantum yields (1ꢀ10ꢁ4
to 2ꢀ10ꢁ3) compared to their parent complex (FPL¼0.15).36 Also
the iridium complex of phenylpyridine ligand with styryl sub-
stituent at position-4 of the phenylpyridine ligand showed very
4-(2-arylvinyl)-8-tosyloxyquinolines produced by Heck coupling
and their yields are shown in Table 1.
OH
N
Br
O
POBr3/DMF
90-95 °C
5-10 min.
N
H
N
OTs
OTs
OTs
2
1
PdCl2/2PPh3
3 mol%
R
R
K2CO3
DMF(40 mL)
130 °C
1) NaOH or
1-butanethiol Na salt
2) HCl
R
N
N
2-3 h
OH
OTs
4a-h
3a-h
week emission and low PL quantum yield (
F
¼0.0005) than its
Scheme 1.
hydrogenated derivatives (
quantum yield at room temperature is attributed to the quenching
F
¼0.54). The low PL intensity and PL
Table 1
property of the trans-styryl moiety.37
The (E)-4-(2-arylvinyl)-8-tosyloxyquinolines produced by Heck coupling and their
In this research, the quench of PL emission caused by cis–trans
photoisomerization in the synthesized Al tris{4-(2-arylvinyl)-8-
hydroxyquinolines (5a–h) can be minimized by adding sub-
stituents to 2- and 6-positions of the styryl group (complex 5f).
yields
Quinoline coupling
producta
Yield %
R
Ph
2. Results and discussion
70
4-Bromo-8-tosyloxyquinoline 2 was prepared in a high yield
(93%) by treating a stirred solution of 4-hydroxy-8-tosyloxy-
quinoline34,35 with phosphorus oxybromide at 90–95 ꢂC.
Ph
N
3a
OTs
C6H4-p-OMe
We investigated the Heck coupling between 2 and styrene and
found that the coupling proceeded efficiently with complete con-
version at 130 ꢂC in dry DMF by using 3 mol % of commercially
available PdCl2/2PPh3 catalyst and with K2CO3 as the base. The
coupling was completed in 2–3 h. Organic bases such as triethyl-
amine and diisopropylamine extended the coupling time (6–10 h)
and reduced the yield noticeably (30–50%). Addition of water to the
reaction mixture caused a cleavage of the tosyl group either from the
substrate 2 or from the products 3. Apparently, the use of anhydrous
coupling conditions during Heck coupling is a prerequisite for effi-
cient production of 4-(2-arylvinyl)-8-tosyloxyquinolines 3 from 2.
The coupling went smoothly under this anhydrous Heck
reaction conditions with all the arylvinyl compounds to give
desired coupling products 3 in good to high yields (67–86%) except
for 4-(2-(pyridin-4-yl)vinyl)-8-tosyloxyquinoline 3g and 4-(2-
(pyridin-2-yl)vinyl)-8-tosyloxyquinoline 3h, the yields of the cou-
pling were 37 and 20%, respectively. We also observed that if the
catalyst loading was increased from 3 mol % to 10 mol % the cou-
pling yields of 4-(2-(pyridin-4-yl)vinyl)-8-tosyloxyquinoline 3g and
4-(2-(pyridin-2-yl)vinyl)-8-tosyloxyquinoline 3h were increased
from 37 and 20% to 98 and 90%, respectively.
69
83
67
70
3b
C6H4-p-OMe
N
OTs
C6H4-p-CN
C6H4-p-CN
C6H4-p-Me
C6H4-p-Cl
3c
N
OTs
C6H4-p-Me
N
3d
OTs
C6H4-p-Cl
It is also worth mentioning that the tosyloxy group was stable to
oxidative addition even at a high catalyst loading (10 mol %) of
PdCl2/2PPh3 used to couple the slowly reacting vinylpyridines and 2.
4-(2-Arylvinyl)-8-tosyloxyquinolines 3 were purified by flash
chromatography on silica gel and they were efficiently hydrolyzed
by using sodium hydroxide34,35 to give 4-(2-arylvinyl)-8-hydroxy-
N
3e
OTs
C6H4-2,4,6-OMe
quinolines
4 in high yields. During the attempted alkaline
hydrolysis of 3c we observed a simultaneous complete hydrolysis of
the cyano group.38 The hydrolysis method for 3c was refined and it
was finally determined that sodium 1-butanethiolate selectively
removed the tosyloxy group to give 4c in high yield (94%).34,39
The overall synthetic route for the production of (E)-4-(2-aryl-
vinyl)-8-tosyloxyquinolines (3a–h) and (E)-4-(2-arylvinyl)-8-
hydroxyquinolines (4a–h) is described in Scheme 1 and the
C6H4-2,4,6-OMeb
86
N
3f
OTs
(continued on next page)

4424
W.A.E. Omar, O.E.O. Hormi / Tetrahedron 65 (2009) 4422–4428
Table 1 (continued )
1.2
5a
5b
5c
5d
5e
5f
Quinoline coupling
Yield %
R
producta
1
0.8
0.6
0.4
0.2
0
N
5g
5h
(37) 98c
3g
N
N
OTs
297
347
397
Wavelength (nm)
447
497
547
N
(20) 90c
Figure 1. Normalized absorption spectra of complexes 5a–h.
3h
N
N
40
OTs
5a
5a
5b
5d
5e
5g
5h
150
120
90
60
30
0
30
5b
1H NMR spectroscopy showed that the E isomer formed selectively.
a
5d
b
c
See Experimental procedure for preparation.
Using PdCl2 (10 mol %) and PPh3 (20 mol %).
20
5e
5f
10
5g
5h
Aluminium complexes (5a–h) were prepared by refluxing the
0
470 520 570 620 670
Wavelength (nm)
ligands (4a–h) and aluminium isopropoxide either in anhydrous
acetone or methanol for 24 h under nitrogen atmosphere. The
synthetic route for Al tris{4-(2-arylvinyl)-8-hydroxyquinoline} is
described in Scheme 2.
R
450
500
550
600
Wavelength (nm)
650
700
R
Figure 2. The PL emission spectra for complexes 5a–h.
N
O
Al
Al isopropoxide
quantum yields are also low compared to the PL intensity and quan-
tum yield of the parent Alq3 (Fig. 2). The weak PL intensity may be
attributed to the quenching of PL, which results from cis–trans
isomerization. Related phenomena have also been observed by other
groups for other metal complexes with styryl substituents.36,37,40
Minimizing the aptitude for cis–trans photoisomerization by
introducing MeO groups to the 2- and 6- positions of the phenyl
ring in the styryl group (complex 5f) enhances the PL intensity and
the relative photoluminescence quantum yield noticeably but the
quantum yield is still lower than the PL quantum yield of the parent
Alq3.41,42
O
N
Dry acetone
N
N
O
OH
4a-h
R
5a-h
R
Scheme 2.
The UV–vis spectra of all complexes (5) (Fig. 1) show two
absorption bands, a strong band in the UV region ranging from 300
to 353 nm and another weaker band in the visible region ranging
from 414 to 445 nm. However, the UV–vis spectrum of 5f has the
both bands in the visible region (at 371 and 414 nm).
0.1
PL emission wavelengths of the aluminium complexes 5a–h
were generally strongly red shifted (56–88 nm) compared with the
5f
¼509 nm).10 The strong red shift can
0.08
0.06
PL emission of parent Alq3
(l
be attributed to an extension of the
p system caused by the styryl
moiety.10,11,36,37,40
We have also studied how different substituents in the styryl
moiety affect the emission wavelength of Al complexes. We
observed that an electron-withdrawing chloro substituent on the
phenyl ring causes a slightly red shifted (7 nm) PL emission com-
0.04
5b
pared with 5a (
l
¼583 nm) while an electron-donating methyl (5d),
5d
0.02
5a
5e
methoxy (5b) and trimethoxy (5f) substituents cause a blue shift (4,
12 and 17 nm, respectively) compared with 5a.
Aluminium complexes 5g and 5h are also red shifted (88 and
83 nm, respectively) compared with the parent Alq3 due to the
extension of conjugation.10,11,36,37,40
5h
5g
0
2.75
2.8
2.85
2.9
Optical band gap
2.95
3
3.05
In general, the PL emission intensities of series 5a–h in solution
(chloroform) at room temperature are low and their relative PL
Figure 3. Optical band gap versus relative PL quantum yield of series 5a–h, the PL
quantum yields are relative to Alq3, which has a quantum yield of 1.

W.A.E. Omar, O.E.O. Hormi / Tetrahedron 65 (2009) 4422–4428
4425
Table 2
4.2. Synthesis of 4-bromo-8-tosyloxyquinoline (2)
The photophysical properties of complexes 5a–h
a
b
c
POBr3 (0.65 g, 2.27 mmol) was added to a stirred solution of
4-hydroxy-8-tosyloxyquinoline 134,35 (1.00 g, 3.17 mmol) in DMF
(30 mL) at 90 ꢂC. Temperature rose spontaneously to 95 ꢂC and
stirring was continued for 10 min at 95 ꢂC. The reaction mixture
was poured into water and neutralized with Na2CO3. The pre-
cipitate was collected by filtration, washed with water and
recrystallized from ethanol/CHCl3 mixture to give 2 as white crys-
Complex
lex(
3)
lem
FPL
Optical
band gapd
5a
5b
5c
5d
5e
5f
429 (1.7ꢀ104)
421 (2.7ꢀ104)
445 (1.1ꢀ104)
426 (1.4ꢀ104)
432 (1.2ꢀ104)
414 (3.2ꢀ104)
442 (8.5ꢀ103)
436 (6.5ꢀ103)
583
571
Nde
579
590
566
597
593
0.0069
0.016
2.89
2.95
2.79
2.92
2.87
2.99
2.81
2.84
Nde
0.013
0.0067
0.085
0.0017
0.0027
tals (1.11 g, 93%). Mp: 148–149 ꢂC; IR (KBr):
n
1174, 1374, 1489, 1583,
2.36 (s, 3H), 7.36–7.41
5g
5h
3073 cmꢁ1. 1H NMR (200 MHz, DMSO-d6):
d
Absorption maximum (nm) and molar absorptivity (L molꢁ1 cmꢁ1) in brackets.
Photoluminescence emission maximum (nm) of 20 mM of sample in chloroform.
a
(d, J¼8.2 Hz, 2H), 7.57–7.61 (d, J¼8.2 Hz, 1H), 7.69–7.81 (m, 3H),
b
c
7.94–7.96 (d, J¼4.8 Hz, 1H), 8.05–8.09 (d, J¼8.5 Hz, 1H), 8.60–8.63
Relative PL quantum yield calculated from the relation used by Velapoldi et al.
(d, J¼4.3 Hz, 1H). 13C NMR (50 MHz, DMSO-d6):
d 21.99, 124.08,
and giving a quantum yield of 1.00 to Alq3.43
d
126.61, 127.25, 128.80, 129.23 (3C), 130.77 (2C), 132.91, 133.79,
142.42, 145.70, 146.47, 151.65. HRMS (MþH)þ calcd for
C16H13NO3SBr: 377.9800, found: 377.9815.
Estimated from the UV–vis spectra by using E¼hC/
n.
e
Not detected.
Figure 3 shows the relationship between the optical band gap
and the calculated relative PL quantum yields43 of the synthesized
complexes 5a,b,d–h. Complex 5f shows a clear deviation from the
other complexes, which indicates that the relative PL quantum
yield can be enhanced considerably by minimizing cis–trans photo-
isomerization in solution.
4.3. General procedures for the synthesis of 4-(2-arylvinyl)-8-
tosyloxyquinolines (3a–h) via Heck coupling
4-Bromo-8-tosyloxyquinoline 2 was dissolved in anhydrous
DMF (40 mL), PdCl2 (3 mol %), PPh3 (6 mol %), anhydrous K2CO3
(1 equiv) and 2 equiv of the arylvinyl compound were added to the
stirred DMF solution at 130 ꢂC. The reaction mixture was stirred at
130 ꢂC for 2.5–3 h under nitrogen atmosphere. DMF was then
evaporated under vacuum and the product was purified by flash
chromatography using the appropriate solvent.
The photophysical properties of the aluminium complexes 5 are
shown in Table 2.
3. Conclusion
Anhydrous Heck coupling conditions using a commercially avail-
able catalyst PdCl2/2PPh3 have been successfully applied to the
synthesis of a series of 4-(2-arylvinyl)-8-tosyloxyquinolines. The
tosyloxy group at position-8 was highly stable to oxidative addition
during anhydrous Heck coupling. The 4-(2-arylvinyl)-8-hydroxy-
quinolines could be obtained easily and in high yields either by
alkaline hydrolysis or by the treatment of 4-(2-arylvinyl)-8-tosyloxy-
quinolines with sulfur nucleophiles such as 1-butanthiol sodium salt.
Aluminium complexes of the 4-(2-aryvinyl)-8-hydroxyquino-
lines can be obtained by reaction of aluminium isopropoxide and
the 4-(2-aryvinyl)-8-hydroxyquinoline in anhydrous acetone or
methanol. The PL emission wavelengths of the Alq3 derivatives are
generally red shifted compared to the emission wavelength of
parent Alq3 (56–80 nm) due to the extension of conjugation. Alq3
derivatives with 4-(2-arylvinyl) substituents have weak PL emis-
sion intensities in solution at room temperature, which can partly
be attributed to quenching of PL emission caused by cis–trans
photoisomerization. Relative PL quantum yields of the aluminium
complexes of the 4-arylvinyl-8-tosyloxyquinolines are lower when
compared with the quantum yield of the parent Alq3.
4.3.1. (E)-4-Styryl-8-tosyloxyquinoline (3a)
4-Bromo-8-tosyloxyquinoline 2 (200 mg, 0.53 mmol), PdCl2
(2.82 mg, 0.016 mmol), PPh3 (8.35 mg, 0.03 mmol), K2CO3
(73.32 mg, 0.53 mmol) and 0.07 mL of styrene were used to prepare
the title compound. Eluent used for flash chromatography was
EtOAc/n-hexane (2:3) to afford 3a (151.4 mg, 71%) as white crystals.
Mp: 151–152 ꢂC; IR (KBr):
n
1179, 1378, 1497, 1584, 1625, 3040 cmꢁ1
2.37 (s, 3H), 7.39–7.59 (m, 8H),
.
1H NMR (200 MHz, DMSO-d6):
d
7.80–7.84 (d, J¼7.6 Hz, 5H), 8.00–8.08 (d, J¼15.8 Hz, 1H), 8.47–8.51
(d, J¼8.5 Hz, 1H), 8.77–8.79 (d, J¼4.5 Hz, 1H). 13C NMR (50 MHz,
DMSO-d6):
d 21.98, 118.28, 122.79, 124.55, 126.77, 128.17, 128.46,
129.20 (3C), 129.64 (2C), 129.66, 130.68 (2C), 133.28, 136.63, 137.11,
142.39, 143.23, 145.94, 146.24, 151.41. HRMS (MþH)þ calcd for
C24H20NO3S: 402.1164, found: 402.1136.
4.3.2. (E)-4-(4-Methoxystyryl)-8-tosyloxyquinoline (3b)
4-Bromo-8-tosyloxyquinoline 2 (200 mg, 0.53 mmol), PdCl2
(2.82 mg, 0.016 mmol), PPh3 (8.35 mg, 0.03 mmol), K2CO3
(73.32 mg, 0.53 mmol) and 0.14 mL of p-methoxystyrene were used
to prepare the title compound. Flash chromatography using ace-
tone/n-hexane (3.5:6.5) afforded compound 3b as yellowish
Minimizing the cis–trans photoisomerization by introducing
substituents at the 2- and 6- positions of the phenyl ring in the
styryl group (e.g., 5f) enhances the PL intensity and the relative PL
quantum yield.
crystals (157.8 mg, 69%). Mp: 142–143 ꢂC; IR (KBr):
1507, 1707, 2835, 2923, 2960, 3034 cmꢁ1 1H NMR (200 MHz,
CDCl3):
n 1177, 1376,
.
d
2.40 (s, 3H), 3.85 (s, 3H), 6.92–6.96 (d, J¼8.8 Hz, 2H), 7.23–
7.28 (m, 3H), 7.40–7.61 (m, 6H), 7.86–7.90 (d, J¼8.3 Hz, 2H), 8.13 (d,
4. Experimental
4.1. General
J¼7.8 Hz, 1H), 8.73–8.75 (d, J¼4.5 Hz, 1H). 13C NMR (50 MHz,
CDCl3):
d 22.07, 55.79, 114.74 (2C), 117.72, 120.33, 122.61, 122.70,
125.91, 128.23, 129.00 (2C), 129.16 (2C), 129.48, 129.83 (2C), 133.63,
135.62, 142.55, 143.38, 145.38, 146.30, 150.85, 160.74. HRMS
(MþNa)þ calcd for C25H21NO4NaS: 454.1089, found: 454.1103.
Commercially available solvents and reagents were used
without any further purification. The solvents were dried with
molecular sieves. Flash chromatography was executed by using
silica gel with 0.04–0.063 mm particle size purchased from Merck
(Finland). NaH used in the preparation of 2,4,6-trimethoxystyrene
was purchased from Merck (Finland). Compound 1 was prepared
from the commercially available xanthurenic acid according to
earlier reported procedures.34,35
4.3.3. (E)-4-(4-Cyanostyryl)-8-tosyloxyquinoline (3c)
4-Bromo-8-tosyloxyquinoline
2 (200 mg, 0.53 mmol), PdCl2
(2.82 mg, 0.016 mmol), PPh3 (8.35 mg, 0.03 mmol), K2CO3 (73.32 mg,
0.53 mmol) and 0.14 mL of 4-cyanostyrene were used to prepare the
title compound. The product was purified using EtOAc/n-hexane
(1:1) as eluent affording (187.6 mg, 83%) of white needles. Mp:

4426
W.A.E. Omar, O.E.O. Hormi / Tetrahedron 65 (2009) 4422–4428
181–182 ꢂC; IR (KBr):
n
1172, 1340, 1504, 2220, 2925, 3331 cmꢁ1. 1H
amounts of chemicals used to prepare the title compound. Aceto-
NMR (200 MHz, DMSO-d6):
d
2.35 (s, 3H), 7.36–7.40 (d, J¼7.5 Hz, 2H),
ne/n-hexane mixture (3:2) was used as eluent to purify the product
by flash chromatography, which was obtained as a white powder
(78.9 mg, 37%). Using PdCl2 (10 mol %) and PPh3 (20 mol %)
under same reaction condition afforded the title compound 3g
7.47–7.50 (d, J¼8.1 Hz, 1H), 7.57–7.65 (m, 2H), 7.77–7.88 (m, 5H),
7.96–8.00 (m, 2H), 8.16 (d, J¼16.2 Hz,1H), 8.46–8.50 (d, J¼9.2 Hz,1H),
8.78–8.80 (d, J¼4.8 Hz, 1H). 13C NMR (50 MHz, DMSO-d6):
d 21.96,
111.56, 118.69, 119.71, 122.91, 124.57, 126.58, 126.97, 128.06, 129.08,
129.18 (3C), 130.68 (2C), 133.22, 133.48 (2C), 134.83, 141.68, 142.37,
142.54,145.91,146.24,151.43. HRMS (MþH)þ calcd for C25H19N2O3S:
427.1116, found: 427.1111.
(209.1 mg, 98%). Mp: 160–161 ꢂC; IR (KBr):
n 1177, 1348, 1588,
2.36 (s, 3H), 7.37–7.41
3045 cmꢁ1. 1H NMR (200 MHz, DMSO-d6):
d
(d, J¼8.1 Hz, 2H), 7.49–7.88 (m, 8H), 8.25–8.33 (d, J¼15.2 Hz, 1H),
8.47–8.51 (d, J¼8.1 Hz,1H), 8.60–8.63 (d, J¼5.5 Hz, 2H), 8.80–8.82 (d,
J¼5.2 Hz, 1H). 13C NMR (50 MHz, DMSO-d6):
d 22.06, 118.94, 122.53,
4.3.4. (E)-4-(4-Methylstyryl)-8-tosyloxyquinoline (3d)
122.55, 124.56, 127.07, 127.59, 128.03, 129.20 (3C), 130.69 (2C),
133.22,134.14,142.37 (2C),144.15,145.93,146.27,151.01 (2C),151.56.
HRMS (MþH)þ calcd for C23H19N2O3S: 403.1116, found: 403.1104.
4-Bromo-8-tosyloxyquinoline 2 (200 mg, 0.53 mmol), PdCl2
(2.82 mg, 0.016 mmol), PPh3 (8.35 mg, 0.03 mmol), K2CO3
(73.32 mg, 0.53 mmol) and 0.14 mL of 4-methylstyrene were used
to prepare the title compound. The product was purified using
acetone/n-hexane (1:2) as eluent giving (147 mg, 67%) as white
4.3.8. (E)-4-(2-(Pyridin-2-yl)vinyl)-8-tosyloxyquinoline (3h)
4-Bromo-8-tosyloxyquinoline 2 (200 mg, 0.53 mmol), PdCl2
(2.82 mg, 0.016 mmol), PPh3 (8.35 mg, 0.03 mmol), K2CO3
(73.32 mg, 0.53 mmol) and 0.11 mL 2-vinylpyridine were used to
prepare the title compound. The product was purified using ace-
tone/n-hexane (1:2) as eluent in flash chromatography giving the
title compound as a white powder (42.7 mg, 20%). Using PdCl2
(10 mol %) and PPh3 (20 mol %) under same previous conditions
solid. Mp: 184–185 ꢂC; IR (KBr):
n
1177, 1376, 1585, 1630, 3037 cmꢁ1
2.36 (s, 3H), 2.40 (s, 3H), 7.25–7.29
.
1H NMR (200 MHz, DMSO-d6):
d
(d, J¼8.3 Hz, 2H), 7.41–7.45 (d, J¼8.6 Hz, 2H), 7.51–7.65 (m, 3H),
7.69–7.76 (m, 2H), 7.82–7.89 (m, 3H), 7.97–8.05 (d, J¼16.2, 1H),
8.49–8.53 (d, J¼8.3 Hz, 2H), 8.78–8.80 (d, J¼5.1 Hz, 1H). HRMS
(MþH)þ calcd for C25H22NO3S: 416.1320, found: 416.1316.
increased the yield to 192 mg, 90%. Mp: 127–128 ꢂC; IR (KBr):
n
1180, 1377, 1584, 3042 cmꢁ1. 1H NMR (200 MHz, DMSO-d6):
d
2.36
4.3.5. (E)-4-(4-Chlorostyryl)-8-tosyloxyquinoline (3e)
(s, 3H), 7.34–7.90 (m, 11H), 8.31–8.41 (m, 2H), 8.64–8.66 (d,
4-Bromo-8-tosyloxyquinoline 2 (200 mg, 0.53 mmol), PdCl2
(2.82 mg, 0.016 mmol), PPh3 (8.35 mg, 0.03 mmol), K2CO3
(73.32 mg, 0.53 mmol) and 0.13 mL of 4-chlorostyrene were used to
prepare the title compound. The product was purified by flash
chromatography using acetone/n-hexane (1:2) as eluent affording
J¼4.1 Hz, 1H), 8.80–8.83 (d, J¼4.6 Hz, 1H). 13C NMR (50 MHz,
DMSO-d6):
d 21.96, 118.9, 122.87, 124.10, 124.30, 124.35, 126.16,
127.16,128.09 (2C),129.20 (2C),130.69,133.24,136.08,137.9,142.35,
142.41, 146.00, 146.25, 150.61, 151.50, 154.86. HRMS (MþH)þ calcd
for C23H19N2O3S: 403.1116, found: 403.1131.
(161.6 mg, 70%) as a white powder. Mp: 144–145 ꢂC; IR (KBr):
1178, 1373, 1586, 1626, 3038 cmꢁ1. 1H NMR (200 MHz, DMSO-d6):
2.40 (s, 3H), 7.40–7.45 (d, J¼8.3 Hz, 2H), 7.50–7.65 (m, 5H), 7.82–
n
4.4. General procedure for synthesis of 4-(2-arylvinyl)-8-
hydroxyquinoline (4a, 4b and 4d–h)
d
7.90 (m, 5H), 8.06–8.14 (d, J¼16.2, 1H), 8.50–8.54 (d, J¼8.3 Hz, 1H),
8.81–8.83 (d, J¼4.7 Hz, 1H). 13C NMR (50 MHz, DMSO-d6):
d 22.02,
4-(2-Arylvinyl)-8-tosyloxyquinolines 3a,b and d–h were dis-
solved in ethanol (25 mL) and NaOH (1 M, 5 equiv) was then added.
The mixture was refluxed for 1 h, then more water was added and
the mixture was neutralized with HCl (1 M). The precipitate formed
was filtered, washed with water and dried in an oven at 50 ꢂC for
3 h.
118.32, 123.00, 123.69, 125.00, 126.85, 128.14, 129.23 (2C), 129.67
(2C), 130.18 (2C), 130.72 (2C), 133.30, 134.20, 135.29, 136.12, 142.43,
143.04, 145.96, 146.28, 151.44. HRMS (MþH)þ calcd for
C24H19NO3SCl: 436.0774, found: 436.0774.
4.3.6. (E)-4-(2,4,6-Trimethoxystyryl)-8-tosyloxyquinoline (3f)
The following amounts of chemicals were used to prepare the title
compound: 4-bromo-8-tosyloxyquinoline 2 (200 mg, 0.53 mmol),
PdCl2 (2.82 mg, 0.016 mmol), PPh3 (8.35 mg, 0.03 mmol), K2CO3
(73.32 mg, 0.53 mmol) and 0.14 mL of 2,4,6-trimethoxystyrene,44
which was prepared in 98% yield as yellowish oil by stirring meth-
yltriphenylphosphonium bromide (1.365 g, 3.8 mmol) and NaH
(0.15 g, 3.75 mmol) in THF for 2 h at room temperature followed by
the addition of 2,4,6-trimethoxybenzaldehyde (0.5 g, 2.5 mmol),
reflux for 2 h and flash chromatography using an acetone and n-
hexane mixture (1:2). The title compound 3f was purified by flash
chromatography using EtOAc/n-hexane (1:2) as eluent affording
(224.1 mg, 86%) of 3f as bright yellow powder. Mp: 133–134 ꢂC; IR
4.4.1. (E)-4-Styrylquinolin-8-ol (4a)
4-Styryl-8-tosyloxyquinoline 3a (0.5 g, 1.25 mmol) and NaOH
(1 M, 6.23 mL, 6.23 mmol) were used to prepare the title com-
pound. The product was collected and recrystallized from
a CHCl3/EtOH mixture giving a reddish powder (0.3 g, 99%). Mp:
180–181 ꢂC; IR (KBr):
(200 MHz, CDCl3):
n
1508, 1566, 1624, 3051, 3312 cmꢁ1. 1H NMR
d
7.19–7.26 (t, J¼7.0 Hz, 1H), 7.32–7.54 (m, 5H),
7.62–7.83 (m, 5H), 8.74–8.77 (d, J¼4.5 Hz, 1H). 13C NMR (50 MHz,
CDCl3):
d 110.12, 114.12, 118.00, 123.19, 127.04, 127.57 (2C), 127.98,
129.32 (3C), 135.61, 136.86, 139.24, 143.58, 147.86, 152.96. HRMS
(MþH)þ calcd for C17H14NO: 248.1075, found: 248.1028.
(KBr):
n
1166,1201,1605, 2837, 2938 cmꢁ1.1H NMR (200 MHz, DMSO-
4.4.2. (E)-4-(4-Methoxystyryl)quinolin-8-ol (4b)
d6): 2.36 (s, 3H), 3.82 (s, 3H), 3.89 (s, 6H), 6.31 (s, 2H), 7.36–7.64 (m,
d
4-(4-Methoxystyryl)-8-tosyloxyquinoline 3b (1.0 g, 2.32 mmol)
and NaOH (1 M, 11.6 mL, 11.6 mmol) were used to prepare the title
compound. The product was collected by filtration and recrystal-
6H), 7.79–7.82 (d, J¼7.9 Hz, 2H), 8.10–8.17 (m, 2H), 8.70–8.72 (d,
J¼4.9 Hz,1H).13C NMR (50 MHz, DMSO-d6):
d 21.96, 56.24, 56.83 (2C),
91.80, 107.04, 117.50, 122.20, 122.49, 124.00, 126.32, 127.61, 128.08,
129.19 (2C),130.64 (2C),133.28,142.30,145.28,146.00,146.20,151.50,
160.72 (3C), 162.42. HRMS (MþH)þ calcd for C27H26NO6S: 492.1481,
found: 492.1485.
lized from
powder (0.58 g, 91%). Mp: 172–173 ꢂC (lit.11 163–165 ꢂC); IR (KBr):
1250, 1570, 1605, 3022, 3326 cmꢁ1. 1H NMR (200 MHz, CDCl3):
3.8
a CHCl3/EtOH mixture to give a reddish brown
n
d
(s, 3H), 6.94–6.98 (d, J¼8.8 Hz, 2H), 7.18–7.28 (m, 2H), 7.49–7.71
(m, 6H), 8.71–8.74 (d, J¼4.4 Hz, 1H). 13C NMR (50 MHz, DMSO-d6):
4.3.7. (E)-4-(2-(Pyridin-4-yl)vinyl)-8-tosyloxyquinoline (3g)
4-Bromo-8-tosyloxyquinoline 2 (200 mg, 0.53 mmol), PdCl2
(2.82 mg, 0.016 mmol), PPh3 (8.35 mg, 0.03 mmol), K2CO3
(73.32 mg, 0.53 mmol) and 0.11 mL 4-vinylpyridine were the
d 56.06, 111.75, 114.67, 115.08 (2C), 117.43, 120.78, 127.44, 128.08,
129.87 (2C), 129.94, 135.50, 139.94, 143.46, 148.42, 154.31,
160.69. HRMS (MþH)þ calcd for C18H16NO2: 278.1181, found:
278.1176.

W.A.E. Omar, O.E.O. Hormi / Tetrahedron 65 (2009) 4422–4428
4427
4.4.3. (E)-4-(4-Methylstyryl)quinolin-8-ol (4d)
4.5. Cleavage of tosyl group by 1-butanthiol sodium salt:
4-(4-Methylstyryl)-8-tosyloxyquinoline 3d (200 mg, 0.48 mmol)
and (1 M, 2.4 mL, 2.4 mmol) NaOH were used to prepare the title
compound. The precipitate formed was collected and recrystallized
from EtOH/CHCl3 mixture to give the product 4d as a yellow powder
synthesis of (E)-4-(4-cyanostyryl)quinolin-8-ol (4c)
NaH (47.3 mg, 1.97 mmol) in a 60% oil dispersion was washed
with n-pentane (4 mL), and then 1-butanthiol (0.2 mL, 1.97 mmol)
was added. The mixture was stirred at room temperature for 10 min
and 4-(4-cyanostyryl)-8-tosyloxyquinoline 3c (280 mg, 0.66 mmol)
in tert-amyl alcohol was then added and the whole mixture was
refluxed for 1 h. After cooling, water was added to the mixture to
dissolve the deep red precipitate formed and the mixture was neu-
tralized with HCl (1 M). The precipitate formed was collected by
filtration and recrystallization from EtOH gave a yellow powder
(124.5 mg, 99%). Mp: 154–155 ꢂC; IR (KBr):
n
1401, 1508, 1561, 1623,
2.36 (s, 3H), 7.12–
3048, 3325 cmꢁ1. 1H NMR (200 MHz, DMSO-d6):
d
7.15 (d, J¼7.7 Hz, 1H), 7.25–7.29 (d, J¼8.1 Hz, 2H), 7.47–7.61 (m, 2H),
7.72–7.67 (d, J¼7.7 Hz, 2H), 7.89–8.03 (m, 3H), 8.81–8.84 (d, J¼4.5 Hz,
1H), 9.80 (br, OH). 13C NMR (50 MHz, DMSO-d6):
d 21.83,111.83,114.69,
117.76, 122.29, 127.49, 128.35 (2C), 130.29 (2C), 134.56, 135.80, 139.28,
139.96,143.29,148.49,154.38 (2C). HRMS (MþH)þ calcd for C18H16NO:
262.1232, found: 262.1237.
(168.1 mg, 94%). Mp: 210–211 ꢂC; IR (KBr):
3288 cmꢁ1. 1H NMR (200 MHz, DMSO-d6):
7.09–7.13 (d, J¼6.5 Hz,
1H), 7.44–7.7.66 (m, 2H), 7.85–8.24 (m, 7H), 8.81–8.83 (d, J¼4.3 Hz,
1H), 9.86 (br, 1H). 13C NMR (50 MHz, DMSO-d6):
111.41, 112.10,
n 1508, 1599, 2216,
d
4.4.4. (E)-4-(4-Chlorostyryl)quinolin-8-ol (4e)
d
4-(4-Chlorostyryl)-8-tosyloxyquinoline 3e (0.5 g, 1.15 mmol) was
refluxed with NaOH (1 M, 5.75 mL, 5.75 mmol). The precipitate formed
was collected by filtration and recrystallized from CHCl3/EtOH giving
the title compound as a yellowish powder (0.3 g, 94%). Mp: 142–
114.00,118.34, 119.88, 127.26,127.46,128.49,129.00 (2C),133.49 (2C),
134.08, 139.95, 141.86, 142.45, 148.82, 154.42. HRMS (MþH)þ calcd
for C18H13N2O: 273.1028, found: 273.1038.
143 ꢂC; IR (KBr):
(200 MHz, DMSO-d6):
n .
1213, 1404, 1562, 1629, 3272 cmꢁ1 1H NMR
4.6. General procedure for the preparation of aluminium
complexes (5a–h)
d
7.13–7.16 (d, J¼7.9 Hz, 1H), 7.48–7.64 (m, 4H),
7.87–8.12 (m, 5H), 8.84–8.86 (d, J¼4.3 Hz, 1H), 9.82 (br, OH). 13C NMR
(50 MHz, DMSO-d6):
d 111.94, 114.74, 118.04, 124.35, 127.50, 128.35,
4-(2-Arylvinyl)-8-hydroxyquinolines (4a–h) were refluxed with
aluminium isopropoxide in dry acetone or methanol for 24 h. The
reaction mixture was then concentrated and the precipitate was
filtered and washed with acetone.
128.67 (2C), 130.08 (2C), 134.01, 134.50, 136.27, 139.97, 142.94, 148.47,
154.41. HRMS (MþH)þ calcd for C17H13NOCl: 282.0686, found:
282.0694.
4.4.5. (E)-4-(2,4,6-Trimethoxystyryl)quinolin-8-ol (4f)
4.6.1. Al tris(4-styryl-8-hydroxyquinoline) (5a)
4-(2,4,6-Trimethoxystyryl)-8-tosyloxyquinoline 3f (0.5 g, 1 mmol)
was reacted with NaOH (1 M, 5.1 mL, 5.1 mmol). The precipitate
formed was recrystallized from EtOH/CHCl3 mixture to give the title
compound as a yellow powder (0.34 g, 99%). Mp: 159–160 ꢂC; IR (KBr):
4-(Styryl)-8-hydroxyquinoline 4a (200 mg, 0.81 mmol) and
aluminium isopropoxide (55 mg, 0.27 mmol) gave the title com-
pound as an orange powder (167 mg, 81%). 1H NMR (200 MHz,
DMSO-d6):
d
6.76–6.80 (d, J¼8.1 Hz, 1H), 6.92–6.96 (d, J¼7.4 Hz,
n
1209, 1509, 1606, 2836, 2937, 3004, 3307 cmꢁ1. 1H NMR (200 MHz,
2H), 7.33–8.05 (m, 31H), 8.55–8.58 (d, J¼4.7 Hz, 1H), 8.69–8.72 (d,
J¼4.1 Hz, 1H). HRMS (MþH)þ calcd for C51H37N3O3Al: 766.2650,
found: 766.2662.
DMSO-d6):
d
3.84 (s, 3H), 3.91 (s, 6H), 6.33 (s, 2H), 7.07–7.10 (d, J¼7.9 Hz,
1H), 7.46–7.50 (t, J¼7.5 Hz, 1H), 7.59–7.68 (m, 3H), 8.05–8.13 (d,
J¼16.8 Hz, 1H), 8.74–8.77 (d, J¼4.7 Hz, 1H). 13C NMR (50 MHz, DMSO-
4.6.2. Al tris{4-(4-methoxystyryl)-8-hydroxyquinoline} (5b)11
4-(4-Methoxystyryl)-8-hydroxyquinoline 4b (150 mg, 0.54 mmol)
and Al isopropoxide (36.9 mg, 0.18 mmol) gave the title compound
(131 mg, 85%) as an orange powder. 1H NMR (200 MHz, DMSO-d6):
d6):
d 56.26, 56.86, 91.86, 107.16, 111.65, 113.99, 116.94, 123.14, 126.80,
127.40,128.19,139.84,145.29,148.00,154.46,160.65 (3C),162.25. HRMS
(MþH)þ calcd for C20H20NO4: 338.1392, found: 338.1394.
d
3.38 (s, 9H), 6.77–6.81 (d, J¼7.4 Hz, 1H), 6.92–7.03 (m, 8H), 7.32–7.34
4.4.6. (E)-4-(2-(Pyridin-4-yl)vinyl)quinolin-8-ol (4g)
(d, J¼5.4 Hz,1H), 7.47–7.98 (m, 21H), 8.54–8.57 (d, J¼4.7 Hz,1H), 8.67–
8.70 (d, J¼5.4 Hz, 1H). HRMS (MþH)þ calcd for C54H43N3O6Al:
856.2967, found: 856.2967.
4-(2-(Pyridin-4-yl)vinyl)-8-tosyloxyquinoline 3g (200 mg, 0.5 mmol)
was refluxed with NaOH (1 M, 2.5 mL, 2.5 mmol). The precipitate formed
was recrystallized from a chloroform/ethanol mixture giving the title
compound as a brown powder (113.5 mg, 92%). Mp: 174–175 ꢂC; IR (KBr):
n
1507,1592, 3030, 3307 cmꢁ1.1H NMR (200 MHz, DMSO-d6):
d 7.09–7.12
4.6.3. Al tris{4-(4-cyanostyryl)-8-hydroxyquinoline} (5c)
4-(4-Cyanostyryl)-8-hydroxyquinoline 4c (200 mg, 0.74 mmol)
and Al isopropoxide (50 mg, 0.25 mmol) gave the title compound as
a deep orange powder (178.9 mg, 87%). 1H NMR (200 MHz, DMSO-
(d, J¼7.6 Hz, 1H), 7.44–7.56 (m, 2H), 7.74–7.92 (m, 4H), 8.22–8.30 (d,
J¼16.6 Hz, 1H), 8.59–8.61 (d, J¼4.7 Hz, 2H), 8.82–8.83 (d, J¼4.3 Hz, 1H),
9.86 (br, OH).13C NMR (50 MHz, DMSO-d6):
d112.23,114.68,118.66,122.48
d6):
d
6.77 (d, J¼6.20 Hz, 1H), 6.92–6.95 (d, J¼5.2 Hz, 2H), 7.38–8.24
(2C), 127.44, 128.25, 128.58, 133.36, 139.95, 142.26, 144.32, 148.59, 151.02
(2C), 154.45. HRMS (MþH)þ calcd for C16H13N2O: 249.1028, found:
249.1029.
(m, 28H), 8.57–8.59 (m, 1H), 8.70–8.72 (m, 1H). HRMS (MþH)þ
calcd for C54H34N6O3Al: 841.2508, found: 841.2522.
4.6.4. Al tris{4-(4-methylstyryl)-8-hydroxyquinoline} (5d)
4.4.7. (E)-4-(2-(Pyridin-2-yl)vinyl)quinolin-8-ol (4h)
4-(4-Methylstyryl)-8-hydroxyquinoline 4d (200 mg, 0.77 mmol)
and Al isopropoxide (52 mg, 0.26 mmol) gave the title complex as an
orange powder (162.8 mg, 79%). 1H NMR (200 MHz, DMSO-d6):
4-(2-(Pyridin-2-yl)vinyl)-8-tosyloxyquinoline 3h (200 mg, 0.5 mmol)
was refluxed with NaOH (1 M, 2.5 mL, 2.5 mmol). The precipitate col-
lected was recrystallized from EtOH/CHCl3 to give the title compound as
d
2.35 (s, 9H), 6.79–6.82 (d, J¼7.5 Hz,1H), 6.94–6.97 (d, J¼6.2 Hz, 2H),
a brownish powder (116 mg, 94%). Mp: 129–130 ꢂC; IR (KBr):
n
1508,1587,
7.25–7.36 (m, 7H), 7.54–7.74 (m, 16H), 7.92–8.02 (m, 5H), 8.56–8.58
(d, J¼4.4 Hz,1H), 8.70–8.8.72 (d, J¼5.0 Hz,1H). HRMS (MþNa)þ calcd
for C54H42N3O3NaAl: 830.2939, found: 830.2921.
3055, 3313 cmꢁ1.1H NMR (200 MHz, DMSO-d6):
d
7.07–7.08 (d, J¼7.8 Hz,
1H), 7.31–7.87 (m, 7H), 8.32–8.40 (d, J¼15.6 Hz, 1H), 8.62–8.64 (d,
J¼3.9 Hz,1H), 8.80–8.82 (d, J¼4.4 Hz,1H), 9.84 (br, OH).13CNMR(50 MHz,
DMSO-d6):
d
112.02, 114.31, 118.49, 124.22 (2C), 126.96, 127.50, 128.81,
4.6.5. Al tris{4-(4-chlorostyryl)-8-hydroxyquinoline} (5e)
135.26, 138.04, 139.93, 142.27, 148.55, 150.60, 154.53, 155.01. HRMS
4-(4-Chlorostyryl)-8-hydroxyquinoline 5d (200 mg, 0.71 mmol)
and Al isopropoxide (48 mg, 0.24 mmol) gave the title compound as an
(MþH)þ calcd for C16H13N2O: 249.1028, found: 249.1029.

4428
W.A.E. Omar, O.E.O. Hormi / Tetrahedron 65 (2009) 4422–4428
orange powder (173 mg, 84%). 1H NMR (200 MHz, DMSO-d6):
3. Mekouar, K.; Mouscadet, J. F.; Desmaele, D.; Subra, F.; Leh, H.; Savoure, D.;
Auclair, C.; D’angelo, J. J. Med. Chem. 1998, 41, 2846.
d
6.79–6.83 (d, J¼6.9 Hz,1H), 6.95–6.99 (d, J¼6.6 Hz, 2H), 7.73–8.12 (m,
4. Zouhiri, F.; Mouscadet, J. F.; Mekouar, K.; Desmaele, D.; Savoure, D.; Leh, H.;
Subra, F.; Bret, M. L.; Auclair, C.; D’angelo, J. J. Med. Chem. 2000, 43, 1533.
5. Zouhiri, F.; Danet, M.; Benard, C.; Normand-Bayle, M.; Mouscadet, J. F.; Leh, H.;
Thomas, C. M.; Mbemba, G.; D’angelo, J.; Desmaele, D. Tetrahedron Lett. 2005,
46, 2201.
26H), 8.59–8.61 (d, J¼4.4 Hz, 1H), 8.72–8.75 (d, J¼4.1 Hz, 1H). HRMS
(MþNa)þ calcd for C51H33N3O3NaAlCl3: 890.1301, found: 890.1318.
4.6.6. Al tris{4-(2,4,6-trimethoxystyrene)-8-hydroxyquinoline} (5f)
4-(2,4,6-Trimethoxystyryl)-8-hydroxyquinoline 4f (200 mg,
0.59 mmol) and Al isopropoxide (40 mg, 0.20 mmol) gave the title
complex as a yellow powder (176 mg, 86%). 1H NMR (200 MHz,
6. Ouali, M.; Laboulais, C.; Leh, H.; Gill, D.; Desmaele, D.; Mekouar, K.; Zouhiri, F.;
D’angelo, J.; Auclair, C.; Mouscadet, J. F.; Le Bret, M. J. Med. Chem. 2000, 43, 1949.
7. Zouhiri, F.; Desmaele, D.; D’angelo, J.; Ourevitch, M.; Mouscadet, J. F.; Leh, H.; Le
Bret, M. Tetrahedron Lett. 2001, 42, 8192.
8. Norman-Bayle, M.; Benard, C.; Zouhiri, F.; Mouscadet, J. F.; Leh, H.; Thomas, C.
M.; Mbemba, G.; Desmaele, D.; D’angelo, J. Bioorg. Med. Chem. Lett. 2005, 15,
4019.
9. Courcot, B.; Firley, D.; Fraisse, B.; Becker, P.; Gillet, J. M.; Pattison, P.; Chernyshov,
D.; Sghaier, M.; Zouhiri, F.; Desmaele, D.; D’Angelo, J.; Bonhomme, F.; Geiger, S.;
Ghermani, N. E. J. Phys. Chem. B 2007, 111, 6042.
CDCl3):
d
3.85–3.91 (m, 27H), 6.16–6.18 (m, 6H), 7.07–7.15 (t, J¼7.6,
8.1 Hz, 3H), 7.27–7.78 (m, 13H), 8.07–8.20 (m, 3H), 8.75–8.78 (t,
J¼4.1 Hz, J¼4.6 Hz, 2H). HRMS (MþH)þ calcd for C60H55N3O12Al:
1036.3601, found: 1036.3623.
10. Barberis, V. P.; Mikroyannidis, J. A. Synth. Met. 2006, 156, 865.
11. Chen, M. Y.; Hsu, M. A.; Liu, C. Y.; Chow, T. J. J. Chin. Chem. Soc. 2004, 51, 735.
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4.6.7. Al tris{4-(2-(pyridin-4-yl)vinyl)quinolin-8-ol} (5g)
4-(4-Vinylpyridinyl)-8-tosyloxyquinoline 5g (200 mg, 0.81 mmol)
and Al isopropoxide (55 mg, 0.27 mmol) gave the title compound as
a deep orange powder (171 mg, 83%). 1H NMR (200 MHz, DMSO-d6):
d
6.80–6.83 (d, J¼7.1 Hz, 1H), 6.97–7.22 (d, J¼7.1 Hz, 2H), 7.41–7.92 (m,
19H), 8.03–8.06 (d, J¼4.8 Hz,1H), 8.21–8.33 (m, 3H), 8.62–8.64 (m, 6H),
8.76–8.78 (d, J¼4.6 Hz, 1H). HRMS (MþH)þ calcd for C48H34N6O3Al:
769.2508, found: 769.2511.
4.6.8. Al tris{4-(2-(pyridin-2-yl)vinyl)quinolin-8-ol} (5h)
4-(2-Vinylpyridinyl)-8-hydroxyquinoline 4h (200 mg, 0.81 mmol)
and Al isopropoxide (55 mg, 0.27 mmol) gave the title compound as an
orange powder (161 mg, 78%). 1H NMR (200 MHz, DMSO-d6):
d
6.82–6.85 (d, J¼6.46 Hz, 1H), 6.99–7.02 (d, J¼7.2 Hz, 2H), 7.36–7.95
(m, 20H), 7.97–7.99 (d, J¼4.9 Hz,1H), 8.08–8.09 (d, J¼5.7,1H), 8.32–8.43
(m, 3H), 8.62–8.69 (m, 4H), 8.77–8.79 (d, J¼4.9 Hz,1H). HRMS (MþH)þ
calcd for C48H34N6O3Al: 769.2508, found: 769.2519.
Acknowledgements
The authors thank Mrs. Paivi Joensuu for the HRMS and Fortum
Foundation for the financial support.
Supplementary data
Supplementary data associated with this article can be found in
the online version, at doi:10.1016/j.tet.2009.03.028.
37. Lepeltier, M.; Le Bozec, H.; Guerchais, V. Organometallics 2005, 24, 6069.
38. HRMS (MþH)þ for the hydrolysis product of 3c by NaOH alcoholic solution
gave: calcd: 291.1134 for C18H15N2O2, found: 291.1138.
39. Heiskanen, J. P.; Hormi, O. E. O. Tetrahedron 2009, 65, 518.
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41. Ji, Z.; Li, L. Y.; Sun, W. Inorg. Chem. 2008, 47, 7599.
References and notes
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quantum yield of Alq3 was taken as 1.00.
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