5-Bromopyridine-2-carbonitrile

5-Bromopyridine-2-carbonitrile is a pyridine with a bromine atom at C-5 and a nitrile group at C-2.

Suzuki and Heck coupling. Under Suzuki conditions it couples with substituted phenylboronic acids to give 5-aryl-2-pyridinecarbonitriles. It also gives a dinitrile in a Heck coupling with 2,2′-bifuran-5-carbonitrile.

Amidines from the nitrile. Azaterphenyl diamidines have been made from it in two steps, starting with coupling to 1,4-phenylenebisboronic acid. In that route, the bis-nitriles were converted to the diamidines with LiN(TMS)₂ in THF. These diamidines were evaluated for in vitro antiprotozoal activity.

Cross-electrophile coupling. It was the model aryl bromide in a nickel-mediated, net-reductive cross-electrophile coupling with an alkyl N-hydroxyphthalimide ester, driven by photoactive electron donor–acceptor complexes.

Triazine formation. With ammonium bromide and diisopropylethylamine it forms 2,4,6-tris(5-bromopyridin-2-yl)-1,3,5-triazine. Palladium-catalysed coupling of this tribromide with 4-aminophenylboronic acid pinacol ester gives the matching triamine. That triamine and the matching trialdehyde are the two monomers of a triazine-based covalent organic framework.

Cysteine conjugation. 2-Cyanopyridines with electron-withdrawing groups react efficiently with cysteine under aqueous, mild conditions, which allows N-terminal cysteine bioconjugation. 5-Bromopyridine-2-carbonitrile itself reacts with cysteine to give a thiazoline.

Diketopyrrolopyrrole polymers. As the monobrominated starting material, it places one bromine atom on the pyridine unit of an unsymmetric DPP, enabling a type II regioregular polymer. Pyridine-DPP is a building block for low band-gap donor copolymers in polymer solar cells.