Rapid and scalable synthesis of innovative unnatural α,β or γ-amino acids functionalized with tertiary amines on their side-chains.

We report a selective ruthenium catalyzed reduction of tertiary amides on the side chain of Fmoc-Gln-OtBu derivatives, leading to innovative unnatural α,β or γ-amino acids functionalized with tertiary amines. Rapid and scalable, this process allowed us to build a library of basic unnatural amino acids at the gram-scale and directly usable for liquid- or solid-phase peptide synthesis. The diversity of available tertiary amines allows us to modulate the physicochemical properties of the resulting amino acids, such as basicity or hydrophobicity.

Diketopyrrolopyrrole-porphyrin conjugates with high two-photon absorption and singlet oxygen generation for two-photon photodynamic therapy.

Two-photon photodynamic therapy is a promising therapeutic method which requires the development of sensitizers with efficient two-photon absorption and singlet-oxygen generation. Reported here are two new diketopyrrolopyrrole-porphyrin conjugates as robust two-photon absorbing dyes with high two-photon absorption cross-sections within the therapeutic window. Furthermore, for the first time the singlet-oxygen generation efficiency of diketopyrrolopyrrole-containing systems is investigated.

Functionalized two-photon absorbing diketopyrrolopyrrole-based fluorophores for living cells fluorescent microscopy.

Two-photon excited microscopy has evolved as a routine technique for long-term cellular and in vivo imaging and is now available in most optical microscopy facilities. Classical dyes and fluorescent proteins, developed for epifluorescence or confocal microscopy, are used but unfortunately present a low efficiency upon two-photon excitation inducing the need of high excitation power (over 20 mW). To reduce this excitation power, new dyes need to be developed, allowing really low two-photon excitation power in the milliwatt or sub-milliwatt range.