Synthesis and properties of geometrical 4-diarylmethylene analogs of the green fluorescent protein chromophore.

We have developed a novel analog of the GFP chromophore: geo-DAIN. Since geo-DAIN is equipped with an E/Z-photoisomerizable geometrical diarylmethylene moiety instead of benzylidene of the GFP chromophore, different-colored reversible emissions are expected. We synthesized geo-DAIN by a condensation with methyl imidate and N-(diarylmethylene)glycinate. We found the emission from geo-DAIN to be different from that of benzylidene-type analogs; in the powder state, the E- and Z-isomers of geo-DAIN emitted different fluorescence colors.

A hybrid molecule of a GFP chromophore analogue and cholestene as a viscosity-dependent and cholesterol-responsive fluorescent sensor.

Diarylmethylenated and cholestene (or -tane)-hybrid analogues of the GFP chromophore, namely, Ch-DAINs were successfully synthesised by a condensation reaction between methyl imidates and N-(diarylmethylene)glycinates. Among the Ch-DAINs synthesised, a diphenyl-type analogue showed viscosity-dependent and cholesterol-responsive fluorescent properties. It showed a nearly linear increase of the fluorescence emission in triglycerides and vesicles as the amount of cholesterol was increased.

Green Synthesis of (R)-Terbutaline for Recyclable Catalytic Asymmetric Transfer Hydrogenation in Ionic Liquids.

We synthesize optically active (R)-terbutaline 2, which is an anti-asthmatic drug, through recyclable catalytic asymmetric transfer hydrogenation (RCATH). Various chloroketones 4 were prepared and RCATH was performed on them. The products exhibit moderate to high enantioselectivity. In particular, the hydrogenation of acyl substituted substrates 4c yields chiral secondary alcohols 5c in good yield and enantioselectivity. Furthermore, (R)-terbutaline 2 can be synthesized in one step from the resulting secondary alcohol 5 without racemization.

Design and concise synthesis of a novel type of green fluorescent protein chromophore analogue.

A small molecular model compound for the green fluorescent protein chromophore was readily synthesized by a novel condensation reaction of (thio)imidate with imino-ester via an aziridine intermediate. This compound showed fluorescence in the solid and frozen solution states but not in the solution state. Its fluorescent property was successfully applied in the detection of dsDNA.