Synthesis and Properties of 6-Aryl-4-azidocinnolines and 6-Aryl-4-(1,2,3-1H-triazol-1-yl)cinnolines

Synthesis of Functionalized Dibenzoazacyclooctynes by a Decomplexation Method for Dibenzo-Fused Cyclooctyne-Cobalt Complexes

A concise route for dibenzoazacyclooctynes (DIBACs) synthesis was developed based on Pictet-Spengler reaction and a novel cobalt decomplexation method established for dibenzo-fused cyclooctyne-cobalt complexes. The method allowed for the facile preparation of functionalized DIBACs, including bisDIBAC, which served as an efficient bisreactive linker for protein modification via the double-click reaction.

Efficient method for the synthesis of novel methyl 4-cinnolinecarboxylate

A new method is designed for the synthesis of some novel methyl 3-aryl/alkyl-4-cinnolinecarboxylate with developed a general Richter cyclization through diazotization strategy of commercially available 2-aryl/alkyl ethynyl aniline and methyl acetate. Most substrates were achieved in moderate to excellent yields in one-pot procedures under mild reaction conditions.

4-Azidocinnoline-Cinnoline-4-amine Pair as a New Fluorogenic and Fluorochromic Environment-Sensitive Probe

A new type of fluorogenic and fluorochromic probe based on the reduction of weakly fluorescent 4-azido-6-(4-cyanophenyl)cinnoline to the corresponding fluorescent cinnoline-4-amine was developed. We found that the fluorescence of 6-(4-cyanophenyl)cinnoline-4-amine is strongly affected by the nature of the solvent. The fluorogenic effect for the amine was detected in polar solvents with the strongest fluorescence increase in water. The environment-sensitive fluorogenic properties of cinnoline-4-amine in water were explained as a combination of two types of fluorescence mechanisms: aggregation-induced emission (AIE) and excited state intermolecular proton transfer (ESPT). The suitability of an azide-amine pair as a fluorogenic probe was tested using a HepG2 hepatic cancer cell line with detection by fluorescent microscopy, flow cytometry, and HPLC analysis of cells lysates. The results obtained confirm the possibility of the transformation of the azide to amine in cells and the potential applicability of the discovered fluorogenic and fluorochromic probe for different analytical and biological applications in aqueous medium.

Tuneable access to indole, indolone, and cinnoline derivatives from a common 1,4-diketone Michael acceptor

A convergent strategy is reported for the construction of nitrogen-containing heterocycles from common substrates: 1,4-diketones and primary amines. Indeed, by just varying the substrates, the substituents, or the heating mode, it is possible to selectively synthesize indole, indolone (1,5,6,7-tetrahydroindol-4-one), or cinnoline (5,6,7,8-tetrahydrocinnoline) derivatives in moderate to excellent yields.