As eries of novel iodinated NO 2 -substituted azaBODIPYs have been synthesized and characterized.H ighly desirable photophysical and photochemical properties were induced in NO 2 -substituted aza-BODIPYs by iodinationo ft he pyrrole rings. In particular, highv alues of singlet oxygen quantum yields (F D )r anging from 0.79 to 0.85 were measured. The photooxygenation process proceeds via aT ype II mechanism under the experimental conditions applied. The compounds studied exhibited an absorption band within the so-called "therapeutic window", with l max located between 645 nm to 672 nm. They were non-fluorescent at room temperature with excited singlet-state lifetimes within the picosecond range as measured by femtosecond transient absorption. Nanosecond laser flash photolysis experiments revealed T 1 !T n absorption spanning from ca. 400 nm to ca. 500 nm and allowedd etermination of the triplet-state lifetimes. The estimated triplet lifetimes (t T )i nd eaerated acetonitrile ranged between 2.74 msa nd 3.50 ms. As estimated by CV/DPV measurements, all iodinateda za-BODIPYs studied exhibited one irreversible oxidation and two quasireversible reductions processes. Estimation of the E HOMO gave the value of À6.06 to À6.26 eV while the E LUMO was found to be located at ca. À4.6 eV.T hermogravimetric (TGA) analysis revealed that iodinated aza-BODIPYs weres table up to approximately 300 8C. All compounds studied exhibit high photostability in toluene solution.

Protein arylation has attracted much attention for developing new classes of bioconjugates with improved properties. Here, we have systematically evaluated 2-sulfonylpyrimidines as covalent warheads for the mild, chemoselective and metal free cysteine S-arylation. 2-sulfonylpyrimidines react rapidly with cysteine, resulting in stable S-heteroarylated adducts at neutral pH. Fine tuning the heterocyclic core and exocyclic leaving group allowed predictable SNAr reactivity with model tripeptide glutathione in vitro, covering 9 orders of magnitude. We achieved extremely fast chemo- and regio- specific arylation of a mutant p53 protein, and confirmed arylation sites by protein X-ray crystallography. Hence, we report the first example of a protein site specifically S-arylated with iodo-aromatic motifs. Overall, this study provides the most comprehensive structure-reactivity relationship to date on heteroaryl sulfones, and highlights 2-sulfonylpyrimidine as a synthetically tractable and protein compatible covalent motif for targeting reactive cysteines, expanding the arsenal of tunable warheads for modern covalent ligand discovery.

Copper-on-charcoal is an excellent heterogeneous catalyst for the alkyne–azide cycloaddition reaction performed under continuous flow conditions. 2-Ynoic acids undergo decarboxylation/cycloaddition cascade giving triazoles bearing small alkyl chains.

In a flow photochemical process switching off the light source and monitoring the reaction composition as it leaves the photoreactor allows the effect of all irradiation times up to a...