Ring-opening reaction of 2,5-dioctyldithieno[2,3-b:3',2'-d]thiophene in the presence of aryllithium reagents

Article abstract of DOI:10.3762/bjoc.9.87

In this paper, the ring-opening reaction of 2,5-dioctyldithieno[2,3-b:3', 2'-d]thiophene with aryllithium in THF at low temperature to generate 2'-arylthio-3,3'-bithiophene-2-carbaldehydes is studied. Nine examples are explored and all the products are ch

Full text of DOI:10.3762/bjoc.9.87

Ring-opening reaction of 2,5-dioctyl-
dithieno[2,3-b:3',2'-d]thiophene in the presence of
aryllithium reagents
Hao Zhong1, Jianwu Shi1, Jianxun Kang2, Shaomin Wang2, Xinming Liu1
and Hua Wang*1
Full Research Paper
Open Access
Address:
Beilstein J. Org. Chem. 2013, 9, 767–774.
1Key Lab for Special Functional Materials of Ministry of Education,
Henan University, Kaifeng, 475004, China and 2Department of
Chemistry, Zhengzhou University, Zhengzhou, 450001, China
doi:10.3762/bjoc.9.87
Received: 12 January 2013
Accepted: 29 March 2013
Published: 19 April 2013
Email:
Shaomin Wang - hwang@henu.edu.cn; Hua Wang* -
hwang@henu.edu.cn
Associate Editor: T. P. Yoon
* Corresponding author
© 2013 Zhong et al; licensee Beilstein-Institut.
License and terms: see end of document.
Keywords:
aryllithium reagents; 2'-arylthio-3,3'-bithiophene-2-carbaldehyde;
dithieno[2,3-b:3',2'-d]thiophene; nucleophilicity; ring-opening reaction
Abstract
In this paper, the ring-opening reaction of 2,5-dioctyldithieno[2,3-b:3',2'-d]thiophene with aryllithium in THF at low temperature to
generate 2'-arylthio-3,3'-bithiophene-2-carbaldehydes is studied. Nine examples are explored and all the products are characterized
by 1H NMR, 13C NMR and HRMS. The relative relationship between the structures of aryl groups and the efficiency of ring-
opening reactions are discussed.
Introduction
Due to the promising optical and electrical properties, the work, we reported the synthesis of a series of symmetric substi-
derivatives of dithieno[2,3-b:3',2'-d]thiophene (DTT), as one tuted dithieno[2,3-b:3',2'-d]thiophenes and their ring-opening
type of fused oligothiophene, have shown their potential appli- reactions in the presence of n-BuLi. The 3,3'-bithiophene-2-
cations in organic electronics [1-4]. The work on the synthesis carbaldehydes were generated after quenching with an elec-
of DTT derivatives and the chemical stability of the DTT core trophile, i.e., dry DMF (Scheme 1) [5].
is of particular interest. To construct DTT functional materials,
deprotonation of DTT with organolithium reagents seems to be The uncommon ring opening of fused thiophene derivatives in
one of the most important approaches. However, the ring- the presence of n-BuLi, though it has been reported, does not
opening reaction of DTT leading to the cleavage of the center draw as much attention as the ring opening of other hetero-
ring can be observed in the presence of n-BuLi. In our previous cyclic compounds [6-9]. The limited number of reports include
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Beilstein J. Org. Chem. 2013, 9, 767–774.
Nine aryllithium reagents were employed for the ring-opening
reaction of 1 as shown in Table 1. The molecular structures and
the effects of electron-donating groups (EDG) and electron-
withdrawing groups (EWG) of the aryllithium reagents were
studied. Compared to the compound 2d (Table 1, entry 4)
bearing EWG groups, the compounds 2b, 2c and 2e (Table 1,
entries 2, 3 and 5), all of which have EDG groups, generated
higher yields of products, namely 73% (3b), 74% (3c) and 83%
(3e), respectively. In the case of 2b, not only was 3b obtained,
but also a byproduct with similar polarity, 2'-butylsulfanyl-5,5'-
Scheme 1: The ring-opening reaction of symmetric 2,5-disubstituted-
dithieno[2,3-b:3',2'-d]thiophenes in the presence of n-BuLi in THF.
derivatives of benzo[b]thiophene [10-12], thieno[3,2-d]thiazole dioctyl-[3,3'-bithiophene]-2-carbaldehyde [5], was generated
[10,11], and thieno[3,2-b]thiophene [13]. More recently, Nenaj- when the metal–halogen exchange temperature was set to
denko et al. reported that fused thieno[2,3-b]thiophenes and −78 °C. If the reaction temperature of the metal–halogen
some [3,2-b]-fused oligothiophenes were attacked by organo- exchange was set to −78 °C first, and then warmed up to −30 °C
lithium reagents resulting in the cleavage of thiophene rings for 3 h, only 3b could be generated in 70% yield (Table 1, entry
[14]. They found when competitive deprotonation of the sub- 3). The byproduct formed in the case of 2b implies that the
strate was possible, high selectivity towards the ring opening metal–halogen exchange cannot be completed at −78 °C.
was observed with n-BuLi when compared with other organo-
lithium reagents. However, most of these ring-opening reac- Similar to the case of 2e bearing the EDG group of triphenyl-
tions mentioned above take place by using n-BuLi as the amine, 2h also gave a good yield of 3h (76%, Table 1, entry 8).
nucleophile to attack the sulfur atoms of thiophenes. Other These results indicate that an increase of the electron donating
organolithium reagents have rarely been employed for this kind character of the substituted aryl groups leads to a higher nucleo-
of reaction. Furthermore, the relationship between the nucleo- philicity of the aryllithium reagents and thereby promotes the
philicity of organolithium reagents and the efficiency of the ring process of a ring-opening reaction. On the other hand, in the
opening of fused thiophenes has not been discussed.
case of 2d, which has a cyano group, a poor yield of 3d (42%,
Table 1, entry 4) was obtained due to the high stability of
In this paper, we present the ring opening of 2,5- cyano-aryl anion with a low nucleophilicity.
dioctyldithieno[2,3-b:3',2'-d]thiophene (1) with nine aryl-
lithium reagents and the characterization of the nine corres- The steric hinderance effect can be observed in the case of 2a,
ponding ring-opening products. These studies should facilitate 2f and 2g (Table 1, entries 1, 6 and 7). When the bulkiness of
the understanding of the chemical stability of dithieno[2,3- aryl groups increased from benzene to anthracene, the yields of
b:3',2'-d]thiophene, which may be of importance in both organic ring-opening products decreased from 3a (88%), to 3f (61%)
chemistry and materials science. Furthermore, we show a novel and to 3g (56%). Therefore, the aryllithium reagents with bulky
method for the synthesis of 2'-arylthio-3,3'-bithiophene-2- groups, such as anthryllithium, generate lower yields of ring-
carbaldehydes based on the ring-opening reaction.
opening products than phenyllithium as the nucleophilic
reagent.
Results and Discussion
An interesting result was observed for the metal–halogen
exchange of 1-bromopyrene (2i) with n-BuLi or t-BuLi at
−78 °C, which delivered different types of ring-opening prod-
ucts (Scheme 2). When n-BuLi was used for the metal–halogen
Ring-opening reaction of 2,5-dioctyl-
dithieno[2,3-b:3',2'-d]thiophene in the pres-
ence of aryllithium reagents
The aryllithium reagents (Ar–Li) were obtained from the exchange, the reaction temperature was set at 0 °C for the ring-
metal–halogen exchange of Ar–Br and n-BuLi. To avoid the opening reaction of 1 for 3 h. Instead of the expected product,
possible influence from excess n-BuLi, 1.4 equiv Ar–Br was however, an unexpected ring-opening product 2'-butyl-5,5'-
treated with 1.3 equiv n-BuLi at −78 °C for 2 h to make sure dioctyl-2-(1-pyrenylthio)-3,3'-bithiophene (4, 45%) along with
that only excess Ar–Li (1.3 equiv) was employed for the ring- 1-pyrenecarboxaldehyde (5, 35%) was generated when the reac-
opening reaction. Then a solution of 1 was added at −78 °C, at tion mixture was quenched with dry DMF. If t-BuLi was
which point the reaction mixture was slowly warmed to −30 °C employed for the metal–halogen exchange, only anticipated
for 3 h. After quenching with dry DMF, the corresponding ring- product 3i was obtained in 48% yield and no 4 was observed.
opening products 2'-arylthio-3,3'-bithiophene-2-carbaldehydes The structure of 3i was confirmed by a single-crystal structure
were obtained.
analysis (Figure 1).
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Beilstein J. Org. Chem. 2013, 9, 767–774.
Table 1: The ring opening of 2,5-dioctyldithieno[2,3-b:3’,2’-d]thiophene (1) with aryllithium reagents 2a–i.
Entry
Ar–Br
Yield (%)a
Product
1
88
2a
3a
2
70b
2b
3b
3
71b
2c
3c
4
42
2d
3d
5
83
2e
3e
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Beilstein J. Org. Chem. 2013, 9, 767–774.
Table 1: The ring opening of 2,5-dioctyldithieno[2,3-b:3’,2’-d]thiophene (1) with aryllithium reagents 2a–i. (continued)
6
61
2f
3f
7
8
9
56
2g
3g
3h
3i
76
2h
48c
2i
aYield of the isolated product. bn-BuLi was added at −78 °C then warmed up to −30 °C for 3 h. ct-BuLi was employed instead of n-BuLi.
Scheme 2: The ring-opening reaction of 1 in the presence of n-BuLi and t-BuLi employed for metal–halogen exchange.
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Beilstein J. Org. Chem. 2013, 9, 767–774.
Figure 1: Crystallographic structure of 3i (left, top view) and crystal packing (right). Carbon, silicon, oxygen and sulfur atoms are depicted with
thermal ellipsoids set at 50% probability level, and all hydrogen atoms are omitted for clarity.
In our work, the metal–halogen exchange of 1-bromopyrene is another factor that could influence the yield. This ring
(2i) with n-BuLi or t-BuLi at −78 °C delivered different types opening can be applied extensively to derivatives including
of ring-opening products. We believe that the two 2'-arylthio-3,3'-dithiophenyl-2-aldehydes, which may provide
metal–halogen exchange processes went to complete conver- access to a broad range of compounds for pharmaceutical chem-
sion. The formation of 4 is possibly due to the in situ genera- istry, organic chemistry and materials science.
tion of n-BuBr that is trapped by the carbanion generated from
an attack of pyrenyllithium (PyLi) on the central sulfur atom of Experimental
1. The presence of the pyrene carbanion intermediate is respon- Synthesis of 2'-phenylsulfanyl-5,5'-dioctyl-[3,3'-
sible for the formation of 5 by dry DMF quenching. However, if bithiophene]-2-carbaldehyde (3a): To a solution of 2a
t-BuLi was used for the metal–halogen exchange, t-BuBr could (49.7 mg, 0.32 mmol, 1.4 equiv) in dry THF (10 mL), n-BuLi
not be efficiently generated due to the fast elimination occur- (2.38 M in hexane, 0.12 mL, 0.29 mmol, 1.3 equiv) was added
ring between the formed t-BuBr and another equivalent of dropwise at −78 °C. After stirring at −78 °C for 2 h, a solution
t-BuLi. The formed pyrene–Li attacks the sulfur center of 1 and of 1 (95.0 mg, 0.23 mmol, 1.0 equiv) in dry THF (10 mL) was
generates the carbanion intermediate via a ring-opening mecha- added dropwise. The mixture was slowly warmed to −30 °C for
nism, which was quenched only by dry DMF, resulting in 3i.
3 h, then dry DMF (0.04 mL, 0.45 mmol, 2.0 equiv) was added
dropwise at −78 °C, and the reaction mixture was slowly
warmed to ambient temperature overnight. After quenching
with H2O (30 mL), the reaction mixture was extracted with
CHCl3 (2 × 30 mL) and then washed with H2O (30 mL). After
drying over MgSO4, the solvent was removed in vacuum. The
residue was purified by column chromatography on silica gel
with petrol ether (60–90 °C)/chloroform (1:4, v/v) as eluents to
yield 3a (105.1 mg, 88.4%) as a light yellow oil. 1H NMR
(400 MHz, CDCl3) δ 9.70 (s, 1H), 7.22–7.19 (m, 2H),
7.14–7.07 (m, 3H), 6.87 (s, 1H), 6.82 (s, 1H), 2.82 (t, J = 7.6
Hz, 2H), 2.79 (d, J = 7.4 Hz, 2H), 1.74–1.61 (m, 4H), 1.40–1.27
(m, 20H), 0.90–0.87 (m, 6H); 13C NMR (100 MHz, CDCl3) δ
183.03, 155.28, 150.54, 144.49, 139.86, 137.93, 136.87, 128.83,
128.30, 127.74, 127.16, 126.06, 126.02, 31.71, 31.12, 30.85,
30.56, 30.31, 29.14, 29.11, 29.06, 29.04, 28.98, 28.82, 22.54,
14.01; IR (KBr): 2955, 2926, 2855 (C-H), 1661 (C=O) cm−1;
Crystal structure of 2'-(1-pyrenylsulfanyl)-
5,5’-dioctyl-[3,3’-bithiophene]-2-carbalde-
hyde (3i)
The crystallographic structure of 3i is shown in Figure 1 [15].
The crystal of 3i belongs to the triclinic space group P−1. The
two thiophene rings are linked together in the molecule with a
torsional angle (C3–C4–C5–C6) of 55.4° and a dihedral angle
of 56.1°. The pyrenylsulfanyl group is not coplanar to the
neighboring thiophene ring with a dihedral angle of 79.5° and a
torsion angle (C5–C6–S2–C10) of 89.7°. There are short
contacts of hydrogen bonding found in the crystal packing.
However, no π–π interaction was observed between two pyrene
rings, as usually seen in the crystal (Figure 1, right).
Conclusion
In summary, aryllithium reagents are suitable for the ring HRMS–EI m/z: [M+ + Na] calcd for C31H42OS3Na, 549.2293;
opening of 2,5-dioctyldithieno[2,3-b:3',2'-d]thiophene. We found, 549.2290.
obtained nine ring-opening products. Their yields indicated that
strong nucleophilicity of the aryllithium reagents can intensify Synthesis of 2'-(4-methylphenylsulfanyl)-5,5'-dioctyl-[3,3'-
the efficiency of the ring-opening process, and the steric effect bithiophene]-2-carbaldehyde (3b): The same procedure was
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Beilstein J. Org. Chem. 2013, 9, 767–774.
used as for the synthesis of 3a except that after the addition of 1H), 7.16–7.14 (m, 2H), 6.92 (s, 1H), 6.74 (s, 1H), 6.59–6.56
n-BuLi, the reaction temperature was raised to −30 °C for 3 h, (m, 2H), 2.93 (s, 6H), 2.85 (t, J = 7.6 Hz, 2H), 2.73 (t, J = 7.7
and then cooled back to −78 °C before the addition of 1. From Hz, 2H), 1.72 (quint, J = 6.5 Hz, 2H), 1.65 (quint, J = 7.6 Hz,
the reaction on the 54.2 mg scale of 2b, 90.0 mg (70.3%) of 3b 2H), 1.41–1.28 (m, 20H), 0.89 (t, J = 10.8 Hz, 6H); 13C NMR
was obtained as a yellow oil. 1H NMR (400 MHz, CDCl3) δ (100 MHz, CDCl3) δ 183.48, 155.26, 150.00, 147.86, 145.27,
9.69 (s, 1H), 7.02 (s , 4H), 6.84 (d, J = 1.3 Hz, 2H), 2.80 (t, J = 136.60, 135.78, 132.82, 132.29, 128.57, 127.25, 120.98, 112.59,
7.2 Hz, 2H), 2.79 (t, J = 7.2 Hz, 2H), 2.28 (s, 3H), 1.73–1.63 40.17, 31.74, 31.73, 31.16, 31.01, 30.68, 30.20, 29.18, 29.16,
(m, 4H), 1.39–1.28 (m, 20H), 0.88 (t, J = 6.8 Hz, 6H); 29.09, 29.07, 29.01, 28.94, 22.56, 14.02; IR (KBr): 2954, 2924,
13C NMR (100 MHz, CDCl3) δ 183.28, 155.38, 150.07, 144.78, 2851 (C-H), 1659 (C=O) cm−1; HRMS–EI m/z: [M+ + Na]
139.14, 136.86, 136.41, 134.09, 129.70, 128.44, 128.13, 127.65, calcd for C33H47NOS3Na, 592.2709; found, 592.2712.
127.42, 31.77, 31.18, 30.96, 30.66, 30.35, 29.20, 29.19, 29.12,
29.04, 28.92, 22.60, 20.92, 14.07; IR (KBr): 2956, 2926, 2855 Synthesis of 2'-(1-naphthylsulfanyl)-5,5'-dioctyl-[3,3'-bithio-
(C-H), 1661 (C=O) cm−1; HRMS–EI m/z: [M+ + Na] calcd for phene]-2-carbaldehyde (3f): The same procedure was used as
C32H44OS3Na, 563.2430; found, 563.2437.
for the synthesis of 3a. From the reaction on the 72.4 mg scale
of 2f, 84.7 mg (60.5%) of 3f was obtained as a yellow oil.
Synthesis of 2'-(4-methoxylphenylsulfanyl)-5,5'-dioctyl-[3,3'- 1H NMR (400 MHz, CDCl3) δ 9.76 (s, 1H), 8.22–8.19 (m, 1H),
bithiophene]-2-carbaldehyde (3c): The same procedure was 7.84–7.82 (m, 1H), 7.71 (d, J = 8.2 Hz, 1H), 7.51–7.49 (m, 2H),
used as for the synthesis of 3b. From the reaction on the 7.34 (t, J = 7.56 Hz, 1H), 7.25 (d, J = 7.21 Hz, 1H), 6.87 (s,
61.9 mg scale of 2c, 92.9 mg (70.5%) of 3c was obtained as a 1H), 6.84 (s, 1H), 2.81 (t, J = 7.6 Hz, 2H), 2.75 (t, J = 7.5 Hz,
yellow oil. 1H NMR (400 MHz, CDCl3) δ 9.68 (s, 1H), 2H), 1.70 (quint, J = 7.3 Hz, 2H), 1.59 (quint, J = 7.6 Hz, 2H),
7.13–7.10 (m, 2H), 6.85 (s, 1H), 6.78 (s, 1H), 6.77–6.74 (m, 1.39–1.25 (m, 22H), 0.90 (t, J = 5.8 Hz, 6H); 13C NMR
2H), 3.75 (s, 3H), 2.82 (t, J = 7.6 Hz, 2H), 2.76 (t, J = 7.7 Hz, (100 MHz, CDCl3) δ 183.23, 155.54, 150.30, 144.76, 139.41,
2H), 1.73–1.63 (m, 4H), 1.37–1.27 (m, 20H), 0.90–0.86 (m, 136.91, 134.74, 133.70, 131.40, 128.35, 128.34, 127.71, 127.42,
6H); 13C NMR (100 MHz, CDCl3) δ 183.34, 158.98, 155.41, 127.12, 126.73, 126.39, 126.26, 125.56, 124.25, 31.76, 31.16,
149.24, 144.91, 137.82, 136.78, 131.34, 129.42, 128.46, 127.50, 30.85, 30.60, 30.36, 29.19, 29.12, 29.06, 29.04, 28.88, 22.60,
127.47, 114.57, 55.21, 31.76, 31.17, 31,02, 30.68, 30,29, 29.19, 14.08; IR (KBr): 2956, 2926, 2855 (C-H), 1661 (C=O) cm−1;
29.11, 29.03, 28.94, 22.59, 14.06; IR (KBr): 2958, 2926, 2856 HRMS–EI m/z: [M+ + Na] calcd for C35H44OS3Na, 599.2443;
(C-H), 1661 (C=O) cm−1; HRMS–EI m/z: [M+ + Na] calcd for found, 599.2447.
C32H44O2S3Na, 579.2395; found, 579.2396.
Synthesis of 2'-(9-anthrylsulfanyl)-5,5'-dioctyl-[3,3'-bithio-
Synthesis of 2'-(4-cyanolphenylsulfanyl)-5,5'-dioctyl-[3,3'- phene]-2-carbaldehyde (3g): The same procedure was used as
bithiophene]-2-carbaldehyde (3d): The same procedure was for the synthesis of 3a. From the reaction on the 87.4 mg scale
used as for the synthesis of 3a. From the reaction on the of 2g, 85.8 mg (56.4%) of 3g was obtained as a yellow oil.
60.2 mg scale of 2d, 54.9 mg (42.1%) of 3d was obtained as a 1H NMR (400 MHz, CDCl3) δ 9.60 (s, 1H), 8.62 (d, J = 9.4 Hz,
yellow oil. 1H NMR (400 MHz, CDCl3) δ 9.69 (s, 1H), 7.46 (d, 2H), 8.47 (s, 1H), 7.98 (d, J = 9.1 Hz, 2H), 7.51–7.45 (m, 4H),
J = 7.3 Hz, 2H), 7.05 (d, J = 7.3 Hz, 2H), 6.94 (s, 1H), 6.73 (s, 6.91 (s, 1H), 6.60 ( s, 1H), 2.85 (t, J = 7.6 Hz, 2H), 2.54 (t, J =
1H), 2.85 (t, J = 7.6 Hz, 2H), 2.77 (t, J = 7.5 Hz, 2H), 1.75–1.58 7.7 Hz, 2H), 1.75 (quint, J = 3.0 Hz, 2H), 1.48–1.20 (m, 22H),
(m, 4H), 1.40–1.24 (m, 20H), 0.89–0.86 (m, 6H); 13C NMR 0.89 (dd, J = 6.4 Hz, 12.8 Hz, 6H); 13C NMR (100 MHz,
(100 MHz, CDCl3) δ 182.81, 155.90, 152.59, 145.75, 143.64, CDCl3) δ 183.32, 155.58, 147.19, 145.39, 137.02, 135.14,
141.81, 137.13, 132.37, 128.18, 127.94, 125.80, 121.97, 118.53, 134.08, 133.82, 132.41, 131.76, 130.06, 128.82, 128.76, 128.14,
108.94, 31.77, 31.75, 31.17, 30.95, 30.64, 30.49, 29.19, 29.15, 127.18, 126.94, 126.57, 125.41, 31.82, 31.74, 31.09, 31.06,
29.12, 29.10, 29.06, 28.96, 28.88, 22.60, 14.07; IR (KBr): 2956, 30.77, 30.10, 29.68, 29.27, 29.18, 29.13, 29.09, 20.08, 28.99,
2926, 2856 (C-H), 2228 (C≡N), 1661 (C=O) cm−1; HRMS–EI 22.63, 22.58, 14.07, 14.06; IR (KBr): 2956, 2926, 2856 (C-H),
m/z: [M+ + Na] calcd for C32H41NOS3Na, 574.2244; found, 1649 (C=O) cm−1; HRMS–EI m/z: [M+ + Na] calcd for
574.2243.
C39H46OS3Na, 649.2613; found, 649.2603.
Synthesis of 2'-[4-(N,N-dimethylamino)phenylsulfanyl]-5,5'- Synthesis of 2'-[4-(N,N-diphenylamino)phenylsulfanyl]-5,5'-
dioctyl-[3,3'-bithiophene]-2-carbaldehyde (3e): The same dioctyl-[3,3'-bithiophene]-2-carbaldehyde (3h): The same
procedure was used as for the synthesis of 3a. From the reac- procedure was used as for the synthesis of 3a. From the reac-
tion on the 66.3 mg scale of 2e, 112.2 mg (83.2%) of 3e was tion on the 100.1 mg scale of 2h, 127.4 mg (75.6%) of 3h was
obtained as a yellow oil. 1H NMR (400 MHz, CDCl3) δ 9.72 (s, obtained as a yellow oil. 1H NMR (400 MHz, CDCl3) δ 9.65 (s,
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Beilstein J. Org. Chem. 2013, 9, 767–774.
1H), 7.26–7.22 (m, 3H), 7.06–7.02 (m, 6H), 7.00–6.99 (m, 1H), 5 (24.5 mg, 35%) was also obtained. For 4, 1H NMR
6.98–6.97 (m, 2H), 6.91–6.88 (m, 2H) 6.88 (s, 1H), 6.81 (s, (400 MHz, CDCl3) δ 8.49 (d, J = 9.2 Hz, 1H), 8.18–8.15 (dd, J
1H), 2.85–2.77 (m, 4H), 1.73–1.65 (m, 4H), 1.39–1.26 (m, = 3.6, 7.7 Hz, 2H), 8.07 (d, 1H), 8.04–7.95 (m, 4H), 7.80 (d, J =
20H), 0.90 (td, J = 6.4 Hz, 3.2 Hz, 6H); 13C NMR (100 MHz, 8.1 Hz, 1H), 6.77 (s, 1H), 6.58 (s, 1H), 2.78 (t, J = 7.5 Hz, 2H),
CDCl3) δ 183.28, 155.41, 149.67, 147.28, 146.82, 144.92, 2.69 (t, J = 7.5 Hz, 2H), 2.60 (t, J = 7.6 Hz, 2H), 1.67 (qt, J =
138.63, 136.89, 129.94, 129.55, 129.25, 128.50, 128.27, 127.69, 7.4 Hz, 2H), 1.51–1.42 (m, 4H), 1.32–1.10 (m, 22H), 0.89 (t, J
124.47, 123.63, 123.12, 31.80, 31.78, 31.23, 31.04, 30.75, = 6.8 Hz, 3H), 0.85 (t, J = 7.0 Hz, 3H), 0.80 (t, J = 7.4 Hz, 3H);
30.36, 29.23, 29.21, 29.14, 29.09, 29.00, 22.62, 14.10. IR 13C NMR (100 MHz, CDCl3) δ 149.28, 143.27, 141.10, 139.92,
(KBr): 2956, 2926, 2855 (C-H), 1661 (C=O) cm−1; HRMS–EI 133.08, 131.48, 131.34, 130.95, 129.96, 129.25, 127.62, 127.43,
m/z: [M+ + Na] calcd for C43H51NOS3 Na, 716.3037; found, 127.36, 127.21, 126.07, 126.02, 125.16, 125.11, 124.95, 124.55,
716.3025.
124.45, 123.89, 34.04, 31.83, 31.81, 31.27, 31.22, 30.53, 29.92,
29.71, 29.28, 29.21, 29.15, 29.06, 28.52, 22.66, 22.62, 22.39,
Synthesis of 2'-(1-pyrenylsulfanyl)-5,5'-dioctyl-[3,3'-bithio- 14.11, 13.79; IR (KBr): 3435 (Ar-H), 2956, 2924, 2855 (C-H)
phene]-2-carbaldehyde (3i): The same procedure was used as cm−1; HRMS–EI m/z: [M]+ calcd for C44H54S3, 678.3392;
for the synthesis of 3a except for two differences. One is that found, 678.3382.
t-BuLi (2.6 equiv) was employed for the metal–halogen
exchange, and another one is that the temperature for the ring-
Supporting Information
opening reaction of 1 was set to 0 °C for 3h. From the reaction
on the 87.7 mg (1.4 equiv) scale of 2i, 69.1 mg (47.7%) of 3i
Supporting Information File 1
and a side product, 1-pyrenecarboxaldehyde (27.8 mg, 42.0%)
were generated. 3i was obtained as a light yellow solid, mp
66–68 °C; 1H NMR (400 MHz, CDCl3) δ 9.79 (s, 1H), 8.43 (d,
J = 9.2 Hz, 1H), 8.18–8.16 (m, 2H), 8.08–7.95 (m, 5H), 7.80 (d,
J = 8.1 Hz, 1H), 6.84 (s, 1H), 6.75 (s, 1H), 2.77 (t, J = 7.6 Hz,
2H), 2.63 (t, J = 7.6 Hz, 2H), 1.70–1.63 (m, 2H), 1.47–1.13 (m,
22H), 0.88 (t, J = 6.8 Hz, 3H), 0.85 (t, J = 7.0 Hz, 3H);
13C NMR (100 MHz, CDCl3) δ 183.27, 155.54, 149.92, 144.82,
138.90, 136.93, 131.40, 131.15, 130.71, 130.36, 129.58, 128.27,
128.12, 127.92, 127.62, 127.54, 127.00, 126.12, 125.36, 125.28,
124.94, 124.86, 124.18, 123.54, 31.75, 31.70, 31.15, 30,74,
Characterization data and NMR spectra of all compounds
including the X-ray structure determination of 3i.
[http://www.beilstein-journals.org/bjoc/content/
supplementary/1860-5397-9-87-S1.pdf]
Supporting Information File 2
X-ray crystallographic data file of 3i.
[http://www.beilstein-journals.org/bjoc/content/
supplementary/1860-5397-9-87-S2.cif]
30.52, 30.34, 29.17, 29.10, 29.03, 29.01, 28.84, 22.59, 22.55, Acknowledgements
14.06, 14.04; IR (KBr): 2956, 2926, 2854 (C-H), 1653 (C=O) This research was supported by the National Natural Science
cm−1; HRMS–EI m/z: [M+ + Na] calcd for C41H46OS3Na, Foundation of China (21270255, 51273055, 20972041,
673.2611; found, 673.2603.
50803015) and the Program for Innovation Scientists and Tech-
nicians Troop Construction Projects of Henan Province
Synthesis of 2-butyl-2'-(1-pyrenylsulfanyl)-5,5'-dioctyl-3,3'- (104100510011).
bithiophene (4): To a solution of 2i (93.7 mg, 0.33 mmol,
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