Synthesis and Application of 1-[F]Fluoro-4-isothiocyanatobenzene for Radiofluorination of Peptides in Aqueous Medium.

Conjugation of radiofluorinated prosthetic groups to primary amines of peptides in an aqueous medium is still considerably challenging. Herein, we report a one-pot cascade synthesis of 1-[F]fluoro-4-isothiocyanatobenzene ([F]), an isothiocyanate-functionalized prosthetic group for radiolabeling of various peptides in aqueous medium. The developed compound [F] was synthesized in >99% radiochemical purity with 22.

Direct Organocatalytic Chemoselective Synthesis of Pharmaceutically Active 1,2,3-Triazoles and 4,5'-Bitriazoles.

Carbonyl-containing 1,4,5-trisubstituted- and 1,4-disubstituted-1,2,3-triazoles are well-known for their wide range of applications in pharmaceutical and medicinal chemistry, but their high-yielding metal-free synthesis has always remained challenging, as no comprehensive protocol has been outlined to date. Owing to their structural and medicinal importance, herein, we synthesized various carbonyl-containing 1,4,5-trisubstituted- and 1,4-disubstituted-1,2,3-triazoles and unsymmetrical 4,5'-bitriazoles with high yields and chemo-/regioselectivity from the library of 2,4-diketoesters and azides in a sequential one-pot manner through the combination of organocatalytic enolization, in situ [3 + 2]-cycloaddition, and hydrolysis reactions. The commercial availability of the starting materials/catalysts, diverse substrate scope, performance in a one-pot manner, chemo-/regioselectivity of organo-click reaction, quick synthesis of unsymmetrical 4,5'-bitriazoles, a large number of synthetic applications, and numerous medicinal applications of carbonyl-containing 1,2,3-triazoles are the key attractions of this metal-free organo-click work.

Synthesis and preliminary evaluation of novel PET probes for GSK-3 imaging.

Non-invasive imaging of GSK-3 expression in the brain will help to understand the role of GSK-3 in disease pathology and progression. Herein, we report the radiosynthesis and evaluation of two novel isonicotinamide based F labeled PET probes, [F]2 and [F]6 for noninvasive imaging of GSK3. Among the developed PET probes, the in vitro blood-brain permeability coefficient of 2 (38 ± 20 × 10 cm/s, n = 3) was found to be better than 6 (8.