A range of aza-ullazines, which represent a new heterocyclic core structure, were synthesized through a scalable four-step reaction, including a Sonogashira reaction and metal-free cyclization promoted by p-toluenesulfonic acid. The optical and electrochemical properties of selected derivatives were investigated, they were found to have similar absorption and emission spectra but a higher oxidation potential than the parent ullazine core.

A variety of aza-ullazines were synthesized in one step from readily accessible 3,5-dialkynyl-4-pyrrolopyridine via acylation followed by intramolecular alkynyl carbonyl metathesis. The reaction conditions were optimized, and the preparative scope was studied. The optoelectronic properties of selected aza-ullazines were studied by UV/vis and fluorescence spectroscopy.

No abstract

Pyrrolo[1,2-a]naphthyridines were synthesized from 3-alkynyl-2-([1H]-pyrrol-1-yl)pyridines and 3-alkynyl-4-([1H]-pyrrol-1-yl)pyridines by cycloisomerization. The reactions are performed by application of the Lewis acids PtCl or Bi(OTf) without the need of further additives. With the described methods a number of derivatives containing a variety of functional groups have been synthesized in up to 78% yield.

Chemoselective Suzuki-Miyaura reactions on 3,5-dibromo-2,6-dichloropyridine were studied. The optimized reaction conditions allow for the facile access of 3-aryl- and 3,5-diarylpyridines in good yields. Suzuki-Miyaura reactions of the selectively synthesized 2,6-dichloro-3,5-diarylpyridines gave the corresponding 2,3,5,6-tetraarylpyridines, containing two different aryl moieties.