PAPER
New End-Capped Thiophenes and Oligothiophenes
2205
1H NMR (CDCl3): = 7.02 (d, J = 3.7 Hz, 2 H), 6.96 (d, J = 3.9 Hz,
(6) Müllen, K.; Wegner, G. Adv. Mater. 1998, 10, 433.
2 H), 6.80 (s, 2 H), 3.33 (m, 8 H).
13C NMR (CDCl3): = 136.4, 135.9, 133.4, 124.9, 124.8, 124.7,
123.8, 121.9, 29.7, 28.8.
(7) Bäuerle, P.; Segelbacher, U.; Maier, A.; Mehring, M. J. Am.
Chem. Soc. 1993, 115, 10217.
(8) (a) Schultz, A. J.; Wang, H. W.; Williams, J. M. J. Am.
Chem. Soc. 1986, 108, 7853. (b) Whangbo, M.-H.; William,
J. M.; Schultz, A. J.; Emge, T. J.; Beno, M. A. J. Am. Chem.
Soc. 1987, 109, 90.
MS (EI): m/z (%) = 510 (100, M+), 482 (26), 362 (37).
Anal. Calcd for C20H14S8: C, 47.03; H, 2.76. Found: C, 46.81; H,
2.94.
(9) Hellberg, J.; Moge, M.; von Schütz, J.-U.; Törnroos, K.-W.
Synth. Met. 1997, 86, 1877.
(10) In order to have a useful shorthand nomenclature for the
oligothiophenes, we named TDT for thienodithiine 5 and
TOT for thienooxathiine 7. The oligothiophenes were then
called TDTnT for the dithiino end-capped series, and
TOTnT for the oxathiino end-capped series, where n is the
number of thiophene units, as for the ECnT oligomers7. For
instance, TOT3T 29 is a terthiophene, which is end-capped
with thioxano rings.
(11) A literature search with Beilstein Commander and Scifinder
Scholar in May 2003 found 20 substances containing 5 as a
substructure, other than those reported by us in preliminary
communications. Only 3 of these contain a peripheral
ethylenedithio bridge. No compound with the substructure 6
was found, and only 3 compounds based on 7.
TOT4T (31)
In a procedure analogous to the synthesis of 30, 21 (1.98 g, 8.4
mmol) was reacted with 27 (1.75 g, 4.18 mmol) in the presence of
CsF (3.76 g, 24.8 mmol) and Pd(PPh3)4 (0.26 g, 0.24 mmol), to give
0.934 g (47%) of pure 31; mp (DSC) 302 °C.
1H NMR (CDCl3): = 7.27 (d, J = 3.7 Hz, 2 H), 7.20 (d, J = 3.7 Hz,
2 H), 6.99 (s, 2 H), 4.60 (m, 4 H), 3.15 (m, 4 H).
13C NMR (DMSO-d6, 95 °C): = 149.5, 136.5,135.8, 130.6, 126.2,
125.4, 117.3, 105.3, 67.3, 26.5.
MS (EI): m/z (%) = 478 (97, M+), 450 (24), 346 (100), 214 (56).
Anal. Calcd for C20H14S6O2: C, 50.12; H, 2.95. Found: C, 49.93; H,
2.90.
(12) (a) Zotti, G.; Gallazzi, M. C.; Zerbi, G.; Meille, S. V. Synth.
Met. 1995, 73, 217. (b) Faid, K.; Leclerc, M. Chem.
Commun. 1996, 2761. (c) Goldoni, F.; Langeveld-Voss, B.
M. W.; Meijer, E. W. Synth. Commun. 1998, 28, 2237.
(13) 3-Methoxythiophene (10) is commercially available, but it
can also be readily synthesized from 3-bromothiophene:
Keegstra, M. A.; Peters, T. H. A.; Brandsma, L. Synth.
Commun. 1990, 20, 213.
Acknowledgment
Financial support from the Royal Institute of Technology, Swedish
Natural Science Research Council, and the Ernst Johnson foundati-
on is gratefully acknowledged.
References
(14) The NMR shifts of the thiophene protons of the main
product are more consistent with the structure 13 than with
12. The aromatic part of the spectrum resembles the
spectrum for 16, which is similar to 13, but the shift for the
2-proton is considerable higher than for the 2-proton in 3-
methoxythiophene 10 and other 3-alkoxythiophenes. For
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(22) During the preparation of this manuscript, a similar synthesis
of 27 was reported:Melucci, M.; Barbarella, G.; Sotgiu, G. J.
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(1) Parts of this paper have been presented at ICSM
1998.Hellberg, J.; Remonen, T.; Slätt, J. Synth. Met. 1999,
101, 103.
(2) Present address: Acreo AB, Bredgatan 34, SE-602 21
Norrköping, Sweden.
(3) Present address: Unit for Organic Chemistry, Department of
Biosciences, Karolinska Institute and Södertörn University
College, Novum Research Park, SE-141 57 Huddinge,
Sweden.
(4) Present address: AstraZeneca R&D, SE-151 85 Södertälje,
Sweden..
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Synthesis 2003, No. 14, 2199–2205 © Thieme Stuttgart · New York