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Synthesis 2002(8): 1053-1056
DOI: 10.1055/s-2002-31958
PAPER
© Georg Thieme Verlag Stuttgart · New York

A New, Improved and Convenient Synthesis of 4H-Cyclopenta[2,1-b:3,4-b′]-dithiophen-4-one

Jacek Z. Brzeziński*a, John R. Reynoldsb
a Department of Organic Chemistry, Institute of Chemistry, University of Ł ódź, Narutowicza 68, 90-136 Ł ódź, Poland
Fax: +48(42)6786583; e-Mail: jzb@krysia.uni.lodz.pl;
b Center for Macromolecular Science and Engineering, Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA
e-Mail: reynolds@chem.ufl.edu;
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Publication History

Received 13 March 2002
Publication Date:
03 June 2002 (online)

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Abstract

A new and efficient three-step synthesis of 4H-cyclopenta[2,1-b:3,4-b′]dithiophen-4-one (CDT) (1) is described. This was achieved by a one-pot, regiospecific synthesis of bis(2-iodo-3-thienyl)methanol (13), its subsequent oxidation to the bis(2-iodo-3-thienyl) ketone (14) which after Ullmann coupling yielded the title compound 1.

Key words

regiospecific lithiation - iodination - oxidation - Ullmann coupling - conducting polymers

16

Mp 71.5-73.5 °C (from benzene-hexane, 1:4). 1H NMR (200 MHz, CDCl3): δ = 2.42 (br s, 1 H, OH), 5.88 (d, 1 H, J = 3.3, HOCH), 6.92 (d, 1 H, J = 5.6, 4-H), 7.03 (dd, 1 H, J = 4.9 and 1.4, 4′-H), 7.20-7.25 (m, 1 H, 2′-H), 7.28 (dd, 1 H, J = 4.9 and 3.1, 5′-H), 7.43 (d, 1 H, J = 5.9, 5-H). 13C NMR (50 MHz, CDCl3): δ = 70.6 (HOCH), 74.5 (2-C), 121.5, 126.0, 126.3, 126.6, 131.5, 143.7 (3- or 3′-C), 147.7 (3- or 3′-C). Anal. Calcd for C9H7IOS2: C, 33.55; H, 2.19; S, 19.91. Found: C, 33.64; H, 2.18; S, 19.70.