Sodium Carbonate → 3-Phenylimidazo[1,2-a]pyrazine

Participants

Reaction Conditions

Reaction Steps

3-Bromoimidazo[1,2-a]pyrazine (1.66 g, 7.13 mmol, Intermediate 2), sodium carbonate (3.78 g, 35.6 mmol) and phenylboronic acid (1.043 g, 8.55 mmol) were dissolved in 1,2-dimethoxyethane (DME) (40 ml) and water (20 ml). Bis(triphenylphosphine)palladium (II) chloride (0.250 g, 0.356 mmol) was added and the biphasic solution heated at 80° C. for 16 h. The aqueous phase was extracted with ethyl acetate (3×100 ml) and the combined extracts washed with saturated sodium bicarbonate solution (100 ml), water (100 ml), brine (100 ml) and dried by passing through a hydromatrix cartridge (Varian). The filtrate was concentrated in vacuo to afford a crude oil (2.44 g). The crude product was purified by flash chromatography (Biotage SP4, 40+M, eluting with a 0-100% gradient of ethylacetate in hexane)—(the product elutes in 100% ethyl acetate), to afford 3-phenylimidazo[1,2-a]pyrazine (1.22 g, 6.25 mmol, 88% yield).

Provenance & Evidence