Asymmetric Total Synthesis and Antidepressant Activity of (−)-Sila-mesembranol Bearing a Silicon Stereocenter

Asymmetric total synthesis of (−)-sila-mesembranol, the silicon analog of the natural alkaloid (−)-mesembranol has been achieved in 3.3% yield over 11 steps. The chiral silicon center was enantioselectively constructed via...

Synthetic Routes to Novel Fluorogenic Pyronins and Silicon Analogs with Far-Red Spectral Properties and Enhanced Aqueous Stability

Fluorogenic detection of reactive (bio)analytes is often achieved with "smart" probes, whose activation mechanism causes the release of aniline-based fluorophores. Indeed, the protection-deprotection of their primary amino is the simplest way to induce dramatic and valuable changes in spectral features of the fluorogenic reporter. In this context, and due to their small size and intrinsic hydrophilicity, we focused on pyronin dyes and related heteroatom analogs (i.e., formal derivatives of 3-imino-3H-xanthen-6-amine and its silicon analog) for their use as optically tunable aniline-based fluorophores. To overcome some severe limitations associated with the use of such fluorogenic scaffolds (i.e., poor aqueous stability and spectral features only in the green-yellow spectral range), the synthesis of novel unsymmetrical derivatives of (Si)-pyronins bearing a single bulky tertiary aniline (i.e., N-methylindoline and julolidine) was explored and presented in this Article. This structural alteration has been found to be beneficial to dramatically lower electrophilicity of the meso-position and to reach attractive fluorescence properties within the far-red spectral region.

Synthetic Routes to Novel Fluorogenic Pyronins and Silicon Analogs with Far-Red Spectral Properties and Enhanced Aqueous Stability

Fluorogenic detection of reactive (bio)analytes is often achieved with "smart" probes, whose activation mechanism causes the release of aniline-based fluorophores. Indeed, the protection-deprotection of their primary amino is the simplest way to induce dramatic and valuable changes in spectral features of the fluorogenic reporter. In this context, and due to their small size and intrinsic hydrophilicity, we focused on pyronin dyes and related heteroatom analogs (i.e., formal derivatives of 3-imino-3H-xanthen-6-amine and its silicon analog) for their use as optically tunable aniline-based fluorophores. To overcome some severe limitations associated with the use of such fluorogenic scaffolds (i.e., poor aqueous stability and spectral features only in the green-yellow spectral range), the synthesis of novel unsymmetrical derivatives of (Si)-pyronins bearing a single bulky tertiary aniline (i.e., N-methylindoline and julolidine) was explored and presented in this Article. This structural alteration has been found to be beneficial to dramatically lower electrophilicity of the meso-position and to reach attractive fluorescence properties within the far-red spectral region.

Defect-sensitive performance of silicene sheets under uniaxial tension: mechanical properties, electronic structures and failure behavior

As a silicon analog of graphene, silicene has attracted considerable attention due to its unique physical and chemical properties.