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DOI: 10.1055/s-0028-1087837
Synthesis of Near-Infrared Emitting Naphthalimide Dyes
Contributor(s):Timothy M. Swager, Mindy LevineEast China University of Science and Technology, Shanghai, P. R. of China
Novel Naphthalimide Derivatives with Near-Infrared Emission: Synthesis via Photochemical Cycloaromatization, Fluorescence in Solvents and Living Cell
Tetrahedron Lett. 2009, 50: 22-25
Publication History
Publication Date:
23 March 2009 (online)
Key words
photochemistry - annulation - radical reaction
Significance
Near-infrared (NIR) emitting dyes are of interest for biological applications, as most biological analytes neither absorb nor fluoresce in that region, leading to greater sensitivity. The authors report the synthesis of two novel NIR dyes based on an interesting photochemical cyclization of naphthalimide derivatives, and the use of one of the dyes in imaging Chinese hamster cells.
Comment
The new dyes are synthesized via the photochemical cyclization of dialkyne precursors 4 and 5. The proposed mechanism of the cyclization involves an unusual intramolecular radical-induced 1,3-aromatic hydrogen transfer. The resulting dyes have unusually large Stokes shifts (136 nm and 166 nm for dyes 6 and 7) and red-shifted emissions relative to the parent naphthalimide. Dye 7 was successfully used to image Chinese hamster cells.