An expedient synthesis of N,N-dialkylamino-dihydroxanthene-pyrylium conjugated near-infrared fluorescent dyes

Anthony Romieu (1, 2) , Jean-Alexandre Richard (3)

1 ICMUB - Institut de Chimie Moléculaire de l'Université de Bourgogne [Dijon]
2 IUF - Institut universitaire de France
3 Organic Chemistry

An expedient synthesis of amino-(nor)dihydroxanthene-based fluorophores is reported, proceeding in two steps from commercially available salicylic aldehydes. The synthesis relies on the one-pot construction of the (nor)dihydroxanthene scaffolds through an oxa-Michael/retro-Michael/vinylogous aldol/dehydration cascade sequence. Further extension of the π-conjugated systems through a condensation reaction with a 2,4,6-trisubstituted pyrylium salt led to a novel class of near-infrared (NIR) fluorescent dyes with absorption/emission maxima in polar media in the ranges of 705–778 and 785–828 nm, respectively.

Mots clés: Cascade reactions; NIR dyes; (Nor)dihydroxanthenes; Pyrylium dyes; restricted aza-bodipy; off-on probe; in-vivo; living cells; rational design; far-red; highly fluorescent; chemical biology; absorbing dyes

Domaines: Chimie

Anthony Romieu, Jean-Alexandre Richard. An expedient synthesis of N,N-dialkylamino-dihydroxanthene-pyrylium conjugated near-infrared fluorescent dyes. Tetrahedron Letters, 2016, 57 (3), pp.317 - 320. ⟨10.1016/j.tetlet.2015.12.010⟩. ⟨hal-01391818⟩