5-Bromopyrazine-2,3-diamine → 5-[1-(2-Fluorobenzyl)-1H-pyrazolo[3,4-b]pyridin-3-yl]pyrazine-2,3-diamine

Participants

Reaction Steps

Under argon, 425 mg (1.20 mmol) of the compound from Example 33A were initially charged in 1,4-dioxane (11 ml), and the reaction mixture was purged with argon for 10 min. Thereafter, 0.91 ml (1.80 mmol) of hexabutylditin and 250 mg (1.32 mmol) of 2,3-diamino-5-bromopyrazine were added. Subsequently, 422 mg (0.60 mmol) of bis(triphenylphosphine)palladium(II) chloride were added and the reaction mixture was heated to reflux overnight. Thereafter, the mixture was cooled to RT and filtered through Celite, and the filtrate was concentrated. The residue was admixed with methanol, and the solids were filtered off and discarded. The filtrate was taken up in methanol-dichloromethane, absorbed onto diatomaceous earth and purified on silica gel (eluent: cyclohexane-ethyl acetate 2:1, 1:1). This gave 151 mg (31% purity, 11% of theory) of the title compound. The crude product was converted further without further purification.

Provenance & Evidence