Synthesis of functionalized anthraquinones via coupling reactions of 2,6-diiodo-1,5-dioctyloxy-9,10-anthraquinone

Article abstract of DOI:10.1055/s-2008-1032121

The synthesis of 2,6-bifunctionalized 9,10-anthraquinones bearing two alkoxy groups in the 1- and 5-positions is performed via transition-metal- catalyzed coupling reactions of 2,6-diiodo-1,5-dioctyloxy-9,10-anthraquinone, here reported for the first time

Full text of DOI:10.1055/s-2008-1032121

PAPER
1227
Synthesis of Functionalized Anthraquinones via Coupling Reactions of
2,6-Diiodo-1,5-dioctyloxy-9,10-anthraquinone
Synthesis of
2r
ationalized
nAnthraquinoc
nes esco Babudri,a,b Domenico De Palma,a Gianluca M. Farinola,*a Roberta Ragni,a Francesco Nasoa,b
a
Dipartimento di Chimica, Università degli Studi di Bari, via Orabona 4, 70126 Bari, Italy
Fax +39(080)5442076; E-mail: farinola@chimica.uniba.it
b
CNR Istituto di Chimica dei Composti OrganoMetallici, via Orabona 4, 70126 Bari, Italy
Received 21 December 2007
o-bromobenzaldehydes.20 Aryne annulations,21 thermoly-
sis and subsequent oxidation of appropriate benzocy-
clobutenones,22 or ring closing metathesis of 2,3-diallyl-
1,4-naphthoquinones23 have also been explored. Howev-
er, some annulation processes are poorly efficient and in-
compatible with many functional groups on reagents, or
they require several synthetic steps, harsh reaction condi-
tions, or substrates that are synthetically demanding.
Abstract: The synthesis of 2,6-bifunctionalized 9,10-anthraquino-
nes bearing two alkoxy groups in the 1- and 5-positions is per-
formed via transition-metal-catalyzed coupling reactions of 2,6-
diiodo-1,5-dioctyloxy-9,10-anthraquinone, here reported for the
first time.
Key words: anthraquinone, functionalization, Suzuki, cross-cou-
pling
9,10-Anthraquinones functionalized with amide-,
alkyamino-, arylamino-, and alkoxy-type groups have
been also obtained by reactions involving easily available
9,10-anthraquinones bearing amino4b,e,8 or hydroxyl9c,24
groups, or derivatives of these substrates bearing halogen
atoms,2b,4a,d,7a,25 or tosyloxy26 reactive sites.
The anthraquinone moiety is a recurrent structural motif
in a large number of organic molecules, biological com-
pounds and supramolecular systems with application in
several fields. In fact, various 9,10-anthraquinone deriva-
tives have been investigated and used as antibiot-
ics,1anticancer agents,2 DNA photocleaving oxidants3 or
DNA intercalators,4 as well as algicides,5 organogela-
tors,6pigments in the dyestuff and textile industry,7 or or-
ganic stabilizers against photodegradation of polymers.8
Transition-metal-catalyzed cross-coupling processes of
organometallic compounds with 9,10-anthraquinones
bearing suitable leaving groups represent the most versa-
tile methods for anthraquinone functionalization involv-
ing new C–C bond formation. Furthermore, these
processes enable the synthesis of polymers with 9,10-an-
thraquinone units. Sonogashira coupling processes of ter-
minal alkynes and 9,10-anthraquinoyl bromides or
iodides have been recently investigated.10,27 On the other
hand, few examples of organometallic synthesis of mono-
or disubstituted anthraquinones via palladium-catalyzed
coupling reactions of anthraquinoyl triflates or halides
with arylboronic esters,28 organostannanes,29 and substi-
tuted olefins30 have been reported in the literature so far.
Furthermore, molecular, polymeric, and supramolecular
9,10-anthraquinone-based systems have recently attracted
considerable interest for their potential use as liquid crys-
tals,9 redox switches10 for molecular electronics, chelating
agents11 or ionophores12 for selective cation sensing, het-
erobifunctional reagents for preparation of biochips,13
near infrared absorbing dyes14 for optical data storage, or
guest nonlinear optical dyes.15Recently, donor–an-
thraquinone acceptor16 dyads or triads with photoinduced
charge transfer properties have also been reported for ap-
plications in photovoltaic cells. Finally, 9,10-anthraquino-
ne derivatives are important precursors in the synthesis of
various compounds such as functionalized anthracenes.17
Based on these grounds, the search for efficient and ver-
satile synthetic methodologies leading to variously substi-
tuted 9,10-anthraquinones deserves great attention.
In the framework of our studies dealing with the develop-
ment of organometallic routes to organic materials for
photonics and electronics,31 we report herein a straightfor-
ward methodology for the synthesis of the 2,6-diiodo-1,5-
dioctyloxy-9,10-anthraquinone (1) (Scheme 1) together
with an investigation of the reactivity of this useful build-
ing block in a series of cross-coupling reactions leading to
novel symmetrically 2,6-di(aryl)-9,10-anthraquinones
with alkoxy groups in the 1- and 5-positions (Schemes 2
and 3).
Many synthetic routes to these molecules have been de-
veloped so far, the most common being based on annula-
tion reactions, such as Diels–Alder cycloadditions18 of
substituted dienes and quinones, Friedel–Crafts
condensation19 of benzene derivatives with functionalized
phthalic anhydrides or phthaloyl dichlorides, and tandem
directed ortho-metalation/metal–halogen exchange pro-
cesses involving substituted N,N-diethylbenzamides and
Indeed, compound 1 appears to be a very promising build-
ing block for the synthesis of novel processable oligomer-
ic and polymeric systems for applications in electronics
and optoelectronics. In fact, the introduction of the two n-
octyloxy groups in the 1- and 5-positions should guaran-
tee the resulting materials solubility in common organic
solvents.32 Moreover, the presence of iodine atoms in the
2- and 6-positions of intermediate 1 was considered par-
SYNTHESIS 2008, No. 8, pp 1227–1232
x
x
.
x
x
.2
0
0
8
Advanced online publication: 06.03.2008
DOI: 10.1055/s-2008-1032121; Art ID: Z29407SS
© Georg Thieme Verlag Stuttgart · New York

1228
F. Babudri et al.
PAPER
O
O
OH
O
O
OC8H17
I
O
O
OC8H17
n-C8H17Br
K2CO3
I2, HIO3
CCl4, MeCOOH
reflux
DMF
reflux
I
OH
H17C8O
H17C8O
1 (92%)
2 (89%)
Scheme 1
ticularly interesting. Actually, it has been demonstrated symmetrically dithienyl or terthienyl substituted an-
that connections through the 2- and 6-positions lead to the thraquinones 15 and 16 with extended p conjugation
highest planarity and conjugation in oligo- and polyan- could be obtained by cross-coupling of 1 with the arylbo-
thracenes.33
ronic esters 8 and 9 in 70% and 65% yield, respectively
(Scheme 3 and Table 1).
Compound 1 was obtained in almost quantitative yield via
nucleophilic substitution of the commercially available
1,5-dihydroxy-9,10-anthraquinone with n-octyl bromide,
in the presence of potassium carbonate as a base and re-
fluxing DMF as a solvent, followed by a double iodination
of the resulting product 2 with iodine and iodic acid in
acetic acid and CCl4 as solvents (Scheme 1). The iodina-
tion reaction was performed following a protocol reported
in the literature for the 1-hydroxy- and the 1,8-dihydroxy-
9,10-anthraquinone leading to the 1-hydroxy-2-iodo- and
the 1,8-dihydroxy-2,7-diiodo-9,10-anthraquinone in 48%
and 61% yield, respectively.34 In our case, the iodination
reaction yielded regioselectively the 2,6-diiodo derivative
1 that can be easily isolated in 92% yield by crystallization
from ethanol.
Table 1 Coupling Reactions of 1 with 3–9
Entry Reagent Reaction conditions
Product Yield
%
1
2
3
4
5
6
7
3
4
5
6
7
8
9
Pd(PPh3)4, Na2CO3, EtOH–toluene, 10
90 °C
91
81
77
87
81
70
65
Pd(PPh3)4, toluene,
100 °C
11
12
13
14
15
16
Pd(PPh3)4, CuI, i-Pr2NH, DMF,
80 °C
Pd(OAc)2, PPh3, Et3N, DMF,
80 °C
THF, dioxane, toluene,
110 °C
With the aim of exploring the reactivity of 1 in C–C bond-
forming reactions with unsaturated substrates, various
types of coupling processes were carried out using a series
of commercially available reagents (Scheme 2). The re-
sults and experimental conditions of the coupling reac-
tions are summarized in Table 1. The Suzuki cross-
coupling of 1 with phenylboronic acid 3 performed in eth-
anol/toluene at 90 °C, using Pd(PPh3)4 as a catalyst and
sodium carbonate as a base, afforded the 2,6-diphenylan-
thraquinone 10 in 91% yield. The 2,6-di(2¢-thienyl)an-
thraquinone 11 was prepared in 81% yield via Stille cross-
coupling using commercially available 2-(tributylstan-
nyl)thiophene (4) in anhydrous toluene at 100 °C, in the
presence of Pd(PPh3)4 as a catalyst. Sonogashira and Heck
reactions with phenylacetylene (5) and methyl acrylate (6)
(Scheme 2) were carried out in mild experimental condi-
tions, as reported in Table 1, to afford 12 and 13 in 77%
and 87% yield, respectively. Compound 1 is also reactive
toward pentafluorophenylcopper (7). The reaction was
performed at 110 °C in anhydrous THF–dioxane–toluene,
leading to 14 in 81% yield.
Pd(PPh3)4, Na2CO3, Ag2O,
dioxane, 90 °C
Pd(PPh3)4, Na2CO3, Ag2O,
dioxane, 90 °C
Close scrutiny of the data reported in Table 1 reveals that
2,6-diiodo-1,5-dioctyloxy-9,10-anthraquinone (1) opens
the access, with good to excellent yields, to various func-
tionalized anthraquinones with interesting structural fea-
tures such as the extended p-conjugation and the presence
of electron-donating or electron-withdrawing groups. Be-
sides being interesting in their own right, many of these
compounds appear as suitable precursors for the synthesis
of new functionalized anthracenes.
In conclusion, we have reported a straightforward synthet-
ic route to the new 2,6-diiodo-1,5-dioctyloxy-9,10-an-
thraquinone (1). This compound is shown to be a useful
substrate in many coupling processes allowing the synthe-
sis in high yields of a variety of novel symmetrically 2,6-
difunctionalized 9,10-anthraquinones with alkoxy groups
in the 1- and 5-positions. Besides the results reported
herein, on this basis it can be easily stated that compound
1 is a likely candidate for polymerization reactions that,
due to the presence of the two alkoxy groups should lead
to soluble materials of special interest at least in optoelec-
tronics.
Having verified the versatility of 1 as a substrate in the
most important Pd-catalyzed coupling reactions, we in-
vestigated the possibility of using 1 as a building block for
the preparation of more extended 2,6-bifunctionalized an-
thraquinones.
For this purpose, Suzuki cross-coupling processes ap-
peared convenient because of the wide variety of commer-
cially available arylboronic derivatives. Therefore,
Synthesis 2008, No. 8, 1227–1232 © Thieme Stuttgart · New York

PAPER
Synthesis of 2,6-Bifunctionalized Anthraquinones
1229
O
OC8H17
B(OH)2
3
H17C8O
O
10 (91%)
S
SnBu3
O
OC8H17
S
4
5
S
H17C8O
O
11 (81%)
O
OC8H17
I
O
OC8H17
I
H17C8O
O
H17C8O
O
1
12 (77%)
O
O
OC8H17
O
OMe
6
OMe
MeO
H17C8O
O
O
13 (87%)
F
F
F
F
F
F
F
F
Cu
F
O
OC8H17
F
F
F
7
F
F
H17C8O
F
O
14 (81%)
Scheme 2
O
OC8H17
I
O
O
O
S
O
Pd(PPh3)4, K2CO3
S
S
+
B
n
S
O
I
S
Ag2O, 90 °C
dioxane
n
H17C8O
O
S
O
n
8 (n = 1)
9 (n = 2)
1
15 (n = 1, 70%)
16 (n = 2, 65%)
Scheme 3
All the chemicals were purchased from Sigma Aldrich and used
without further purification. THF, dioxane, and toluene were fresh-
ly distilled from sodium and benzophenone under N2, immediately
prior to use. DMF and Et3N were distilled over CaH2 at reduced
pressure and stored with molecular sieves 4 Å, under N2. The pen-
tafluorophenylcopper (9) was prepared according to the literature.35
Petroleum ether (PE) used refers to the fraction boiling in the range
40–60 °C. Column chromatography was performed using silica gel
60, 40–63 mm from Merck. Merck Silica gel 60 F254 aluminum
sheets were used for analytical TLC analysis. FT-IR spectra were
measured on a PerkinElmer Spectrum BX spectrophotometer using
dry KBr pellets. 1H, 13C NMR, and 19F NMR spectra were recorded
at 400 MHz, 100 MHz, and 376 MHz on Varian Inova 400 spec-
trometer, respectively, or at 500 MHz (1H NMR) and 125 MHz (13C
NMR) on Bruker AM 500 spectrometer, using the residual proton
peaks of CDCl3 at 7.26 ppm, CD2Cl2 at 5.36 ppm, as references for
Synthesis 2008, No. 8, 1227–1232 © Thieme Stuttgart · New York

1230
F. Babudri et al.
PAPER
1H spectra and the signal of CDCl3 at 77.0 ppm for 13C NMR spec-
tra. 19F signal of trichlorofluoromethane was also used as internal
standard at 0.0 ppm. Elemental analyses were done using a Carlo
Erba CHNS-O EA1108-Elemental Analyzer.
1.40 (m, 16 H), 1.42–1.51 (m, 4 H), 1.80 (quint, J = 6.4 Hz, 4 H),
4.09 (t, J = 6.4 Hz, 4 H), 7.15 (d, J = 8.8 Hz, 2 H), 7.31–7.41 (m, 10
H), 7.46 (d, J = 8.8 Hz, 2 H).
13C NMR (125 MHz, CDCl3): d = 14.1, 22.7, 25.8, 29.1, 29.2, 29.4,
31.9, 69.4, 116.3, 124.7, 126.8, 128.0, 129.2, 133.3, 136.4, 137.0,
140.2, 156.6, 185.6.
1,5-Dioctyloxy-9,10-anthraquinone (2)
A suspension of 1,5-dihydroxy-9,10-anthraquinone (5.0 g, 20.8
mmol) and K2CO3 (0.632 g, 45.8 mmol) in anhyd DMF (130 mL)
was heated at 130 °C under N2. Then, n-octyl bromide (88.4 g, 458
mmol) was added dropwise and the mixture was stirred overnight at
130 °C. After cooling to r.t., the solvent was distilled at reduced
pressure and the yellow liquid product was dissolved in Et2O (30
mL). After washing with H2O (5 × 100 mL), the organic layer was
dried (Na2SO4) and the solvent was evaporated under reduced pres-
sure. The yellow-orange solid product 2 (8.59 g, 18.5 mmol) was
isolated in 89% yield by column chromatography over silica gel, us-
ing PE–EtOAc (9:1); mp 96–97 °C (EtOH).
Anal Calcd for C42H48O4: C, 81.78; H, 7.84. Found: C, 81.83; H,
7.82.
1,5-Dioctyloxy-2,6-di(2-thienyl)-9,10-anthraquinone (11)
The diiodoanthraquinone 1 (0.716 g, 1 mmol), 2-(tributylstan-
nyl)thiophene (4; 0.820 g, 2.20 mmol) and the catalyst, Pd(PPh3)4
(0.127 g, 0.11 mmol), were dissolved in anhyd toluene (25 mL) un-
der N2. The mixture was refluxed for 4 d. After cooling to r.t., the
solvent was distilled at reduced pressure and the crude product was
purified by column chromatography over silica gel using PE–
EtOAc (9:1) as the eluent to give a red solid (0.508 g, 81%); mp
113–115 °C (EtOH–H2O, 8:2).
FTIR (KBr): 2950, 2920, 2850, 1670, 1580, 1470, 1450, 1440,
1280, 1250, 1070, 953, 804, 715 cm–1.
1H NMR (500 MHz, CDCl3): d = 0.88 (t, J = 7.0 Hz, 6 H), 1.26–
1.43 (m, 16 H), 1.56 (quint, J = 7.0 Hz, 4 H), 1.94 (quint, J = 7.0 Hz,
4 H), 4.14 (t, J = 7.0 Hz, 4 H), 7.24 (dd, J = 8.1, 1.0 Hz, 2 H), 7.65
(t, J = 8.1 Hz, 2 H), 7.88 (dd, J = 8.1, 1.0 Hz, 2 H).
FTIR (KBr): 2950, 2920, 2850, 1680, 1480, 1460, 1390, 1290,
1260, 1240, 1210, 1040, 819, 693 cm–1.
1H NMR (500 MHz, CDCl3): d = 0.90 (t, J = 6.2 Hz, 6 H), 1.27–
1.38 (m, 16 H), 1.30–1.54 (m, 4 H), 1.80 (quint, J = 6.2 Hz, 4 H),
4.07 (t, J = 6.2 Hz, 4 H), 7.03 (dd, J = 5.1, 3.6 Hz, 2 H), 7.05–7.09
(m, 2 H), 7.11 (d, J = 8.8 Hz, 2 H), 7.32 (dd, J = 5.1, 1.1 Hz, 2 H),
7.55 (d, J = 8.8 Hz, 2 H).
13C NMR (125 MHz, CDCl3): d = 14.1, 22.6, 25.9, 29.0, 29.2, 29.3,
31.8, 69.6, 117.7, 119.4, 120.9, 134.7, 137.4, 159.3, 182.5.
Anal Calcd for C30H40O4: C, 77.55; H, 8.68. Found: C, 77.60; H,
8.61.
13C NMR (125 MHz, CDCl3): d = 14.3, 22.8, 26.0, 29.2, 29.4, 29.5,
32.0, 69.4, 116.4, 124.8, 125.4, 125.6, 127.1, 127.2, 137.2, 137.3,
141.2, 151.2, 185.0.
2,6-Diiodo-1,5-dioctyloxy-9,10-anthraquinone (1)
Anal Calcd for C38H44O4S2: C, 72.57; H, 7.05; S, 10.20. Found: C,
72.61; H, 6.98; S, 10.16.
H2SO4 (30%, 20 mL), I2 (6 g, 23.6 mmol) and HIO3 (2.75 g, 15.5
mmol) were added to a solution of 1,5-dioctyloxy-9,10-an-
thraquinone (2; 12 g, 25.8 mmol) in AcOH (300 mL) and CCl4 (35
mL). The mixture was refluxed for 6 h and, after cooling to r.t., it
was diluted with Et2O (150 mL) and washed with sat. aq soln of
NaHCO3 (4 × 150 mL) and H2O (4 × 150 mL). The organic layer
was dried (Na2SO4) and the solvent removed at reduced pressure.
Purification of the crude red product by crystallization from EtOH
yielded a yellow solid 1 (16.99 g, 92%); mp 174–175 °C (EtOH).
2,6-Bis(phenylethynyl)-1,5-dioctyloxy-9,10-anthraquinone (12)
The co-catalyst CuI (0.016 g, 0.084 mmol) was dissolved under N2
in a solution of 1 (0.300 g, 0.42 mmol) in anhyd toluene (15 mL).
Then, i-Pr2NH (15 mL), phenylacetylene (5; 0.095 g, 0.93 mmol)
and PdCl2(PPh3)2 (0.029 mg, 0.042 mmol) were added under N2 and
the mixture was refluxed for 2 h. After cooling to r.t., the solvent
was distilled at reduced pressure and the crude product was purified
by column chromatography over silica gel using PE–EtOAc (7:3) as
the eluent. The product 12 was isolated as a yellow solid (0.214 g,
77%); mp 141–144 °C (hexane).
FTIR (KBr): 2950, 2920, 2850, 1680, 1560, 1450, 1380, 1310,
1290, 1220, 1180, 1140, 955, 821, 647 cm–1.
1H NMR (500 MHz, CDCl3): d = 0.86 (t, J = 6.4 Hz, 6 H), 1.20–
1.38 (m, 16 H), 1.51 (quint, J = 6.4 Hz, 4 H), 1.85 (quint, J = 6.4 Hz,
4 H), 4.07 (t, J = 6.4 Hz, 4 H), 6.83 (d, J = 9.0 Hz, 2 H), 8.00 (d,
J = 9.0 Hz, 2H).
13C NMR (125 MHz, CDCl3): d = 14.1, 22.6, 25.8, 28.9, 29.2, 31.8,
69.7, 79.1, 118.4, 124.6, 137.9, 146.5, 158.1, 182.6.
FTIR (KBr): 2950, 2920, 2850, 1680, 1670, 1650, 1560, 1460,
1280, 1210, 1110, 1030, 828, 754, 690, 668 cm–1.
1H NMR (500 MHz, CDCl3): d = 0.85 (t, J = 7.0 Hz, 6 H), 1.20–
1.38 (m, 16 H), 1.56 (quint, J = 7.0 Hz, 4 H), 1.91 (quint, J = 7.0 Hz,
4 H), 4.12 (t, J = 7.0 Hz, 4 H), 7.14 (d, J = 8.8 Hz, 2 H), 7.33–7.38
(m, 6 H), 7.62–7.67 (m, 4 H), 7.74 (d, J = 8.8 Hz, 2 H).
13C NMR (125 MHz, CDCl3): d = 14.1, 22.6, 25.9, 29.2, 29.4, 29.7,
31.8, 69.7, 88.3, 92.4, 113.5, 116.8, 123.5, 123.7, 128.2, 131.8,
139.2, 157.8, 182.4.
Anal Calcd for C30H38I2O4: C, 50.29; H, 5.35. Found: C, 50.28; H,
5.31.
1,5-Dioctyloxy-2,6-diphenyl-9,10-anthraquinone (10)
The catalyst, Pd(PPh3)4 (0.127 g, 0.11 mmol), and aq 2 M Na2CO3
(7 mL) were added to a solution of 1 (0.716 g, 1.0 mmol) in a mix-
ture of EtOH (8 mL) and anhyd toluene (40 mL) under N2. After ad-
dition of phenylboronic acid (3; 0.268 g, 2.2 mmol), the mixture
was stirred at 90 °C for 3 h and, then, cooled to r.t. The mixture was
extracted with Et2O (3 × 20 mL), the combined Et2O layers were
dried (Na2SO4), and the solvent was distilled at reduced pressure.
The pale yellow solid 10 was isolated by column chromatography
over silica gel using PE and EtOAc (8:2) as the eluent (0.566 g,
91%); mp 157–159 °C (hexane).
Anal Calcd for C46H48O4: C, 83.10; H, 7.20. Found: C, 83.16; H,
7.15.
Methyl (2E)-3-{6-[(1E)-3-Methoxy-3-oxoprop-1-enyl]-1,5-di-
octyloxy-9,10-dioxo-9,10-dihydroanthracen-2-yl}acrylate (13)
The diiodoanthraquinone 1 (0.200 g, 0.28 mmol), methyl acrylate
(6; 0.072 g, 0.84 mmol), Pd(OAc)2 (0.063 g, 0.028 mmol), Et3N
(0.028 g, 0.28 mmol) and PPh3 (0.029 g, 0.11 mmol) were suspend-
ed in anhyd DMF (10 mL) under N2 and the mixture was refluxed
for 3 h. After cooling to r.t., the solvent was distilled at reduced
pressure affording a dark yellow solid that was purified by column
chromatography with hexane–EtOAc (9:1) as the eluent. The final
FTIR (KBr): 2950, 2920, 2850, 1690, 1480, 1470, 1280, 1210, 822,
754, 706 cm–1.
1H NMR (500 MHz, CDCl3): d = 0.91 (t, J = 6.4 Hz, 6 H), 1.22–
Synthesis 2008, No. 8, 1227–1232 © Thieme Stuttgart · New York

PAPER
Synthesis of 2,6-Bifunctionalized Anthraquinones
1231
product 13 was isolated as an orange solid (0.152 g, 87%); mp 139–
142 °C (hexane).
1H NMR (500 MHz, CDCl3): d = 0.84 (t, J = 6.4 Hz, 6 H), 1.20–
1.34 (m, 16 H), 1.41–1.50 (m, 4 H), 1.83 (quint, J = 6.4 Hz, 4 H),
4.10 (t, J = 6.4 Hz, 4 H), 7.00 (d, J = 3.6 Hz, 2 H), 7.02 (dd, J = 5.2,
3.6 Hz, 2 H), 7.12 (d, J = 3.6 Hz, 2 H), 7.13 (d, J = 8.7 Hz, 2 H),
7.18 (dd, J = 3.6, 1.2 Hz, 2 H), 7.21 (dd, J = 5.2, 1.2 Hz, 2 H), 7.59
(d, J = 8.7 Hz, 2 H).
13C NMR (125 MHz, CDCl3): d = 14.2, 22.7, 25.9, 29.1, 29.2, 29.3,
31.9, 69.5, 116.4, 123.5, 123.8, 124.2, 124.7, 124.9, 127.7, 127.9,
136.9, 137.0, 137.5, 137.7, 140.0, 157.1, 185.0.
FTIR (KBr): 2950, 2920, 2850, 1720, 1700, 1670, 1400, 1300,
1280, 1160, 1120, 976, 826, 668 cm–1.
1H NMR (500 MHz, CDCl3): d = 0.87 (t, J = 6.7 Hz, 6 H), 1.20–
1.42 (m, 16 H), 1.54 (quint, J = 6.7 Hz, 4 H), 1.92 (quint, J = 6.7 Hz,
4 H), 3.82 (s, 6 H), 4.15 (t, J = 6.7 Hz, 4 H), 6.29 (d, J = 15.7 Hz, 2
H), 7.18 (d, J = 8.8 Hz, 2 H), 7.74 (d, J = 8.8 Hz, 2 H), 8.29 (d,
J = 15.7 Hz, 2 H).
Anal Calcd for C46H48O4S4: C, 69.66; H, 6.10; S, 16.17. Found: C,
69.72; H, 6.04; S, 16.13.
13C NMR (125 MHz, CDCl3): d = 14.3, 22.9, 26.0, 29.0, 29.5, 32.0,
51.9, 69.9, 117.5, 119.7, 123.5, 126.9, 134.2, 136.6, 143.7, 159.3,
167.3, 184.7.
2,6-Bis[(2,2¢;5¢,2¢¢)terthien-5-yl]-1,5-dioctyloxy-9,10-anthra-
quinone (16)
Anal Calcd for C38H48O8: C, 72.13; H, 7.65. Found: 72.18; H, 7.58.
The diiodoanthraquinone 1 (0.358 g, 0.5 mmol), Ag2O (0.255 g,
1.10 mmol), Na2CO3 (0.117 g, 1.10 mmol), and the catalyst
Pd(PPh3)4 (0.064 g, 0.06 mmol) were added in sequence to a solu-
tion of 9 (0.412 g, 1.1 mmol) in anhyd dioxane (50 mL) under N2.
The mixture was stirred overnight at 90 °C. After cooling to r.t., the
solvent was distilled at reduced pressure. The crude product was
chromatographed over silica gel using PE–CH2Cl2 (4:6) as the elu-
ent and then crystallized from CH2Cl2–MeOH to afford 16 as a red
solid (0.311 g, 65%); mp 211–213 °C (CH2Cl2–MeOH).
2,6-Bis(pentafluorophenyl)-1,5-dioctyloxy-9,10-anthraquinone
(14)
A solution of iodopentafluorobenzene (0.262 g, 0.89 mmol) in an-
hyd THF (3 ml) was slowly added dropwise to a refluxing suspen-
sion of Mg turnings (0.026 g, 1.07 mmol) in anhyd THF (1.5 mL)
under N2. The refluxing mixture was stirred for 2 h until the com-
plete disappearance of iodopentafluorobenzene. Then, it was cooled
to r.t. under N2, and anhydrous CuBr (0.256 g, 1.8 mmol) was add-
ed. The resulting brown suspension was stirred at r.t. for 1 h, then
anhyd dioxane (l.5 ml) was added and the mixture stirred at r.t. for
1 h. A solution of the dihalide 1 (0.158 g, 0.22 mmol) in anhyd tol-
uene (10 ml) was introduced using a syringe at r.t. under N2, and the
resulting suspension was stirred at 90 °C for 24 h. After cooling to
r.t., the mixture was diluted with Et2O (10 mL) and filtered to re-
move inorganic salts and insoluble by-products. The organic solu-
tion was dried (Na2SO4) and the solvent distilled at reduced
pressure. The purification of the crude product was carried out by
column chromatography over silica gel using PE–CH2Cl2 (6:4) as
the eluent to give a pale yellow solid (0.143 g, 81%); mp 118–
122 °C (EtOH).
FTIR (KBr) 2920, 2849, 1686, 1560, 1455, 1284, 1204, 792, 688
cm–1.
1H NMR (500 MHz, CD2Cl2): d = 0.85 (t, J = 6.5 Hz, 6 H), 1.18–
1.35 (m, 16 H), 1.44–1.51 (m, 4 H), 1.84 (quint, J = 7.5 Hz, 4 H),
4.13 (t, J = 6.3 Hz, 4 H), 7.00 (d, J = 3.5 Hz, 2 H), 7.05 (t-like, J ~
3 Hz, 2 H), 7.11–7.14 (m, 4 H), 7.15 (d, J = 3.5 Hz, 2 H), 7.19 (d,
J = 8.4 Hz, 2 H), 7.21–7.23 (m, 2 H), 7.25–7.28 (m, 2 H), 7.62 (d,
J = 8.5 Hz, 2 H).
13C NMR (125 MHz, CDCl3): d = 14.2, 22.7, 25.9, 29.1, 29.3, 29.4,
32.0, 69.5, 116.4, 123.6, 123.8, 124.0, 124.3, 124.4, 124.6, 124.8,
127.9, 128.0, 136.0, 136.3, 136.9, 137.0, 137.2, 137.4, 140.2, 157.2,
185.0.
FTIR (KBr): 2960, 2930, 2860, 1680, 1520, 1490, 1480, 1290,
1260, 1230, 1070, 986, 827, 800 cm–1.
Anal Calcd for C54H52O4S6: C, 67.74; H, 5.47; S, 20.10. Found: C,
67.80; H, 5.42; S, 20.02.
1H NMR (500 MHz, CDCl3): d = 0.80 (t, J = 6.7 Hz, 6 H), 1.16–
1.30 (m, 16 H), 1.36 (quint, J = 6.7 Hz, 4 H), 1.73 (quint, J = 6.7 Hz,
4 H), 4.03 (t, J = 6.7 Hz, 4 H), 7.15 (d, J = 8.7 Hz, 2 H), 7.37 (d,
J = 8.7 Hz, 2 H).
Acknowledgment
13C NMR (125 MHz, CDCl3): d = 14.0, 22.6, 25.7, 28.8, 29.1, 29.2,
31.8, 69.5, 115.0 (td, JC,F = 19 Hz, JC,F = 5 Hz), 115.9, 116.7,
123.4, 137.0, 137.7, 137.7 (m, 1JC,F = 253 Hz), 140.5 (m, 1JC,F = 252
Hz), 143.9 (m, 1JC,F = 245 Hz), 159.0, 183.4.
This work was financially supported by Ministero dell’Istruzione,
dell’Università e della Ricerca (MIUR) ‘Progetto FIRB 2003 SYN-
ERGY RBNE03S7XZ’ and by Università degli Studi di Bari.
2
3
19F NMR (376 MHz, CDCl3): d = –142.8 (dd, J = 22.3, 7.6 Hz, 2 F),
–156.6 (t, J = 22.3 Hz, 1 F), –163.4 (td, J = 22.3, 7.6 Hz, 2 F).
References
(1) (a) Ueberbacher, B. J.; Osprian, I.; Mayer, S. F.; Faber, K.
Eur. J. Org. Chem. 2005, 1266. (b) Matsumoto, T.; Katsuki,
M.; Jona, H.; Suzuki, K. Tetrahedron Lett. 1989, 30, 6185.
(2) (a) Alderden, R. A.; Mellor, H. R.; Modok, S.; Hambley, T.
W.; Callaghan, R. Biochem. Pharmacol. 2006, 71, 1136.
(b) Pors, K.; Shnyder, S. D.; Teesdale-Spittle, P. H.; Hartley,
J. A.; Zloh, M.; Searcey, M.; Patterson, L. H. J. Med. Chem.
2006, 49, 7013. (c) Waser, M.; Falk, H. Eur. J. Org. Chem.
2006, 1200. (d) Su, Y.-T.; Chang, H.-L.; Shyue, S.-K.; Hsu,
S.-L. Biochem. Pharmacol. 2005, 70, 229. (e) Zagotto, G.;
Supino, R.; Favini, E.; Moro, S.; Palumbo, M. Farmaco
2000, 55, 1.
Anal Calcd for C42H38F10O4: C, 63.31; H, 4.81. Found: C, 63.30; H,
4.80.
2,6-Bis[2,2¢-Dithien-5-yl]-1,5-dioctyloxy-9,10-anthraquinone
(15)
The diiodoanthraquinone 1 (0.716 g, 1 mmol), Ag2O (0.510 g, 2.20
mmol), Na2CO3 (0.233 g, 2.20 mmol), and the catalyst Pd(PPh3)4
(0.127 g, 0.11 mmol) were added in sequence to a solution of 5-
(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2,2¢-bithiophene (8;
0.642 g, 2.20 mmol) in anhyd dioxane (50 mL) under N2. The mix-
ture was stirred overnight at 90 °C. After cooling to r.t., the solvent
was distilled at reduced pressure. Column chromatography over sil-
ica gel of the resulting black crude product using PE–EtOAc (6:4)
as the eluent gave 15 as a red solid (0.554 g, 70%); mp 145–148 °C
(hexane).
(3) (a) Cao, H.; Schuster, G. B. Bioconjugate Chem. 2005, 16,
820. (b) Schuster, G. B. Acc. Chem. Res. 2000, 33, 253.
(c) Henderson, P. T.; Armitage, B.; Schuster, G. B.
Biochemistry 1998, 37, 2991.
FTIR (KBr): 2910, 2850, 1690, 1460, 1450, 1390, 1290, 1200, 802,
(4) (a) Zafrul Azam, A. T. M.; Moriguchi, T.; Shinozuka, K.
686 cm–1.
Chem. Commun. 2006, 335. (b) Kamal, A.; Ramu, R.;
Synthesis 2008, No. 8, 1227–1232 © Thieme Stuttgart · New York

1232
F. Babudri et al.
PAPER
Ramesh Khanna, G. B.; Kumar Saxena, A.; Shanmugavel,
M.; Moti Pandita, R. Bioorg. Med. Chem. Lett. 2004, 14,
4907. (c) Ge, P.; Russel, R. A. Tetrahedron 1997, 53,
17477. (d) Ihara, T.; Inenaga, A.; Takagi, M. Chem. Lett.
1994, 1053. (e) Takenaka, S.; Ihara, T.; Hamano, M.;
Takagi, M. J. Chem. Soc., Chem. Commun. 1990, 1271.
Blessing, B.; Schmidt, R. R. Synthesis 1994, 255.
(19) (a) Effenberger, F.; Buckel, F.; Maier, A. H.; Schmider, J.
Synthesis 2000, 1427. (b) Sartori, G.; Bigi, F.; Tao, X.;
Porta, C.; Maggi, R.; Predieri, G.; Lanfranchi, M.;
Pellinghelli, M. A. J. Org. Chem. 1995, 60, 6588.
(c) Smith, C. W.; Ambler, S. J.; Steggles, D. J. Tetrahedron
Lett. 1993, 46, 7447.
(5) Schrader, K. K.; Dhammika Nanayakkara, N. P.; Tucker, C.
S.; Rimando, A. M.; Ganzera, M.; Schaneberg, B. T. Appl.
Environ. Microbiol. 2003, 5319.
(20) Wang, X.; Snieckus, V. Synlett 1990, 313.
(21) Bhawal, B. M.; Khanapure, S. P.; Zhang, H.; Biehl, E. R.
(6) (a) Terech, P.; Clavier, G.; Bouas-Laurent, H.; Desvergne,
J.-P.; Demé, B.; Pozzo, J.-L. J. Colloid Interface Sci. 2006,
302, 633. (b) Terech, P.; Weiss, R. G. Chem. Rev. 1997, 97,
3133.
(7) (a) Thetford, D.; Chorlton, A. P.; Mason, J. Dyes Pigm.
2004, 62, 235. (b) Grabchev, I.; Philipova, T. Dyes Pigm.
1998, 39, 89. (c) Meng, Q.; Huang, D.; Wei, S.; Chen, L.
J. Appl. Polym. Sci. 2002, 83, 1252.
J. Org. Chem. 1991, 56, 2846.
(22) Liebeskind, L. S.; Iyer, S.; Jewell, C. F. Jr. J. Org. Chem.
1986, 51, 3067.
(23) (a) Van T, N.; D’hooghe, M.; Pattyn, S.; De Kimpe, N.
Synlett 2004, 1913. (b) Kotha, S.; Mandal, K. Tetrahedron
Lett. 2004, 45, 2585.
(24) (a) Catellani, M.; Luzzati, S.; Lupsac, N.-O.; Mendichi, R.;
Consonni, R.; Giacalone, F.; Segura, J. L.; Martín, N. Thin
Solid Films 2004, 451-452, 2. (b) Rajakumar, P.; Ganesan,
K. Synlett 2004, 2236. (c) Teng, C.-H.; Won, S.-J.; Lin,
C.-N. Bioorg. Med. Chem. 2005, 13, 3439.
(8) Sabaa, M. W.; Oraby, E. H.; Abdel Naby, A. S.; Mohamed,
R. R. Eur. Polym. J. 2005, 41, 2530.
(9) (a) Chen, Z.; Swager, T. M. Org. Lett. 2007, 9, 997.
(b) Yamamoto, T.; Muramatsu, Y.; Lee, B.-L.; Kokubo, H.;
Sasaki, S.; Hasegawa, M.; Yagi, T.; Kubota, K. Chem.
Mater. 2003, 15, 4384. (c) Raja, K. S.; Raghunathan, V. A.;
Ramakrishnan, S. Macromolecules 1998, 31, 3807.
(10) van Dijk, E. H.; Myles, D. J. T.; van der Veen, M. H.;
Hummelen, J. C. Org. Lett. 2006, 8, 2333.
(11) Sathiyendiran, M.; Liao, R.-T.; Thanasekaran, P.; Luo,
T.-T.; Venkataramanan, N. S.; Lee, G.-H.; Peng, S.-M.; Lu,
K.-L. Inorg. Chem. 2006, 45, 10052.
(12) (a) Batista, R. M. F.; Oliveira, E.; Costa, S. P. G.; Lodeiro,
C.; Raposo, M. M. M. Org. Lett. 2007, 9, 3201. (b) Kar, P.;
Suresh, M.; Kumar, D. K.; Jose, D. A.; Ganguly, B.; Das, A.
Polyhedron 2007, 26, 1317. (c) Yang, H.; Zhou, Z.; Li, F.;
Yi, T.; Huang, C. Inorg. Chem. Commun. 2007, 10, 1136.
(d) Nejati-Yazdinejad, M. Anal. Sci. 2006, 22, 617.
(e) Barzegar, M.; Mousavi, M. F.; Khajehsharifi, H.;
Shamsipur, M.; Sharghi, H. IEEE Sensors J. 2005, 5, 392.
(f) Shamsipur, M.; Avanes, A.; Javanbakht, M.; Ganjali, M.
R.; Sharghi, H. Anal. Sci. 2002, 18, 875.
(13) Patnaik, S.; Swami, A.; Sethi, D.; Pathak, A.; Garg, B. S.;
Gupta, K. C.; Kumar, P. Bioconjugate Chem. 2007, 18, 8.
(14) (a) Kohl, C.; Becker, S.; Müllen, K. Chem. Commun. 2002,
2778. (b) Fabian, J.; Nakazumi, H.; Matsuoka, M. Chem.
Rev. 1992, 92, 1197.
(25) (a) Mishra, A. K.; Jacob, J.; Müllen, K. Dyes Pigm. 2007, 75,
1. (b) Baqi, Y.; Müller, C. E. Org. Lett. 2007, 9, 1271.
(c) Gouloumis, A.; Lawson, R. C.; Vázquez, P.; Echegoyen,
L.; Torres, T. Tetrahedron 2002, 58, 961. (d) Beletskaya, I.
P.; Averin, A. D.; Bessmertnykh, A. G.; Guilard, R.
Tetrahedron Lett. 2001, 42, 4987. (e) Kim, H.; Schall, O. F.;
Fang, J.; Trafton, J. E.; Lu, T.; Atwood, J. L.; Gokel, G. W.
J. Phys. Org. Chem. 1992, 5, 482. (f) Fang, J. P.; Lu, T.;
Kim, H.; Delgado, I.; Geoffroy, P.; Atwood, J. L.; Gokel, G.
W. J. Org. Chem. 1991, 56, 7059.
(26) Zielske, A. G. J. Org. Chem. 1987, 52, 1305.
(27) (a) Abou-Elkhair, R. A. I.; Netzel, T. L. Nucleosides,
Nucleotides Nucleic Acids 2005, 24, 85. (b) Ma, H.; Kang,
M.-S.; Xu, Q.-M.; Kim, K.-S.; Jen, A. K.-Y. Chem. Mater.
2005, 17, 2896. (c) Yang, J.; Dass, A.; Rawashdeh, A.-M.
M.; Sotiriou-Leventis, C.; Panzner, M. J.; Tyson, D. S.;
Kinder, J. D.; Leventis, N. Chem. Mater. 2004, 16, 3457.
(d) Ivanchikova, I. D.; Lebedeva, N. I.; Shvartsberg, M. S.
Synthesis 2004, 2131. (e) McGale, E. M.; Robinson, B. H.;
Simpson, J. Organometallics 2003, 22, 931.
(28) (a) Gautrot, J. E.; Hodge, P.; Cupertino, D.; Helliwell, M.
New J. Chem. 2007, 31, 1585. (b) Coudret, C.; Mazenc, V.
Tetrahedron Lett. 1997, 38, 5293.
(29) Tamayo, N.; Echavarren, A. M.; Paredes, M. C.; Fariña, F.;
(15) (a) Meng, Q.; Yan, W.; Yu, M.; Huang, D. Dyes Pigm. 2003,
56, 145. (b) Truong, T. V.; Xu, L.; Shen, Y. R. Phys. Rev.
Lett. 2003, 90, 193902.
(16) (a) Luzzati, S.; Scharber, M.; Catellani, M.; Giacalone, F.;
Segura, J. L.; Martin, N.; Neugebauer, H.; Sariciftci, N. S.
J. Phys. Chem. B 2006, 110, 5351. (b) Okamoto, K.;
Hasobe, T.; Tkachenko, N. V.; Lemmetyinen, H.; Kamat,
P. V.; Fukuzumi, S. J. Phys. Chem. A 2005, 109, 4662.
(c) Giacalone, F.; Segura, J. L.; Martín, N.; Catellani, M.;
Luzzati, S.; Lupsac, N. Org. Lett. 2003, 5, 1669.
Noheda, P. Tetrahedron Lett. 1990, 31, 5189.
(30) Gouloumis, A.; González-Rodríguez, D.; Vázquez, P.;
Torres, T.; Liu, S.; Echegoyen, L.; Ramey, J.; Hug, G. L.;
Guldi, D. M. J. Am. Chem. Soc. 2006, 128, 12674.
(31) For reviews, see: (a) Babudri, F.; Farinola, G. M.; Naso, F.;
Ragni, R. Chem. Commun. 2007, 1003. (b) Babudri, F.;
Farinola, G. M.; Naso, F. J. Mater. Chem. 2004, 14, 11.
(32) Winokur, M. J. In Conjugated Polymers-Theory, Synthesis,
Properties and Characterization, Handbook of Conducting
Polymers, 3rd. ed; Skotheim, T. A.; Reynolds, J. R., Eds.;
CRC Press: Boca Raton, 2007, 17–15.
(33) (a) Müller, U.; Adam, M.; Müllen, K. Chem. Ber. 1994, 127,
437. (b) Hodge, P.; Power, G. A.; Rabjohns, M. A. Chem.
Commun. 1997, 73. (c) Ito, K.; Suzuki, T.; Sakamoto, Y.;
Kubota, D.; Inoue, Y.; Sato, F.; Tokito, S. Angew. Chem. Int.
Ed. 2003, 42, 1159.
(34) Galevskaya, T. P.; Moroz, A. A.; Myasnikova, R. N.;
Shvartsberg, M. S. Zh. Org. Khim. 1988, 24, 405; Chem.
Abstr. 1988, 109, 230490.
(35) (a) Heidenhain, S. B.; Sakamoto, Y.; Suzuki, T.; Miura, A.;
Fujikawa, H.; Mori, T.; Tokito, S.; Taga, Y. J. Am. Chem.
Soc. 2000, 122, 10240. (b) Sakamoto, Y.; Suzuki, T.; Miura,
A.; Fujikawa, H.; Tokito, S.; Taga, Y. J. Am. Chem. Soc.
2000, 122, 1832.
(d) Cusack, L.; Marguerettaz, X.; Rao, S. N.; Wenger, J.;
Fitzmaurice, D. Chem. Mater. 1997, 9, 1765.
(17) (a) Park, J.-H.; Chung, D. S.; Park, J.-W.; Ahn, T.; Kong, H.;
Jung, Y. K.; Lee, J.; Yi, M. H.; Park, C. E.; Kwon, S.-K.;
Shim, H.-K. Org. Lett. 2007, 9, 2573. (b) Kim, Y.-H.;
Kwon, S.-K. J. Appl. Polym. Sci. 2006, 100, 2151.
(c) Danel, K.; Huang, T.-H.; Lin, J. T.; Tao, Y.-T.; Chuen,
C.-H. Chem. Mater. 2002, 14, 3860.
(18) (a) Komiyama, T.; Takaguchi, Y.; Tsuboi, S. Synlett 2006,
124. (b) Bailey, D.; Murphy, J. N.; Williams, V. E. Can. J.
Chem. 2006, 84, 659. (c) Tietze, L. F.; Gericke, K. M.;
Güntner, C. Eur. J. Org. Chem. 2006, 4910.
(d) Nechepurenko, I. V.; Shul’ts, E. E.; Tolstikov, G. A.
Russ. J. Org. Chem. 2003, 39, 1436. (e) Khan, A. T.;
Synthesis 2008, No. 8, 1227–1232 © Thieme Stuttgart · New York