Synlett 2006(3): 0450-0454  
DOI: 10.1055/s-2006-926260
LETTER
© Georg Thieme Verlag Stuttgart · New York

Convenient Synthesis of Isocyanate and Isothiocyanate-Substituted Boron Dipyrromethene Dyes and Derivatives

Laure Bonardi, Gilles Ulrich, Raymond Ziessel*
Laboratoire de Chimie Moléculaire, École de Chimie, Polymères, Matériaux (ECPM), Université Louis Pasteur (ULP), 25 Rue Becquerel, 67087 Strasbourg Cedex 02, France
Fax: +33(3)90242635; e-Mail: ziessel@chimie.u-strasbg.fr;
Further Information

Publication History

Received 18 November 2005
Publication Date:
06 February 2006 (online)

Abstract

Starting from nitro-substituted phenyl rings, the preparation of boron dipyrromethene dyes carrying amino functions was achieved in good yields. Conversion of the p-aminophenyl group to the corresponding isocyanate and isothiocyanate is feasible under mild conditions. Various combinations allow the production of luminescent molecules bearing mono- or disubstituted urea or thiourea substituents. When two adjacent amino functions are present, a simple protocol allows the production of pyridine-indole and dipyridophenazine derivatives. The on/off switching of the fluorescence from the nitro to the amino and further to the urea renders these dyes attractive as fluorescent probes.

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Selected data for 8: isolated yield quantitative. 1H NMR (CDCl3): δ = 7.32 (m, 4 H), 2.53 (s, 6 H), 2.30 (q, 4 H, 3 J = 7.5 Hz), 1.30 (s, 6 H), 0.98 (t, 6 H, 3 J = 7.5 Hz) ppm. 13C NMR (CDCl3): δ = 154.5, 138.4, 138.1, 137.2, 135.1, 133.3, 132.3, 130.7, 130.1, 126.5, 17.2, 14.7, 12.7, 12.1 ppm.

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Selected data for 12: 99%. 1H NMR (CDCl3): δ = 7.51 (d, 2 H, 3 J = 8.5 Hz), 7.39-7.32 (m, 4 H), 7.18-7.15 (m, 3 H), 7.00 (br s, 1 H), 6.84 (br s, 1 H), 2.53 (s, 6 H), 2.28 (q, 4 H, 3 J = 7.5 Hz), 1.33 (s, 6 H), 0.96 (t, 6 H, 3 J = 7.5 Hz) ppm. 13C NMR (CDCl3): δ = 153.8, 153.0, 140.1, 139.2, 138.6, 137.9, 133.0, 131.2, 130.6, 129.6, 129.2, 124.8, 121.6, 119.9, 17.2, 14.7, 12.7, 12.1 ppm. 11B NMR (CDCl3): δ = 3.93 (t, 1 J = 32 Hz) ppm. FAB+-MS: m/z (nature of peak, rel. intensity) = 515.2 (100) [M + H]+. Anal. Calcd for C30H33BF2N4O·H2O: C, 67.67; H, 6.63; N, 10.52. Found: C, 67.52; H, 6.52; N, 10.32.

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Selected data for 13: 60%. 1H NMR (CDCl3): δ = 7.94 (br s, 1 H), 7.81 (br s, 1 H), 7.58 (dd, 2 H, 1 J = 1.7 Hz, 3 J = 6.6 Hz), 7.51-7.45 (m, 2 H), 7.39-7.32 (m, 3 H), 7.30-7.28 (dd, 2 H, 1 J = 1.7 Hz, 3 J = 6.6 Hz), 2.52 (s, 6 H), 2.29 (q, 4 H, 3 J = 7.5 Hz), 1.32 (s, 6 H), 0.97 (t, 6 H, 3 J = 7.5 Hz) ppm. 13C NMR (CDCl3): δ = 180.0, 154.1, 139.1, 138.5, 138.3, 136.5, 134.0, 133.1, 130.9, 130.3, 129.4, 127.8, 124.4, 125.1, 17.2, 14.7, 12.7, 12.1 ppm. 11B NMR (CDCl3): δ = 3.85 (t, 1 J = 32 Hz) ppm. FAB+-MS: m/z (nature of peak, rel. intensity) = 531.1 (100) [M + H]+. Anal. Calcd for C30H33BF2N4S·H2O: C, 65.69; H, 6.43; N, 10.21. Found: C, 65.49; H, 6.28; N, 9.93.