Cesium carbonate → HCID 9902790, compound

Participants

Reaction Steps

A mixture of 3-(4-bromothien-2-yl)-7-trifluoromethylimidazo[1,2-α]pyrimidine (104 mg, 0.3 mmol), pyridine-3-boronic acid-1,3-propanediol cyclic ester (73 g, 0.45 mmol), cesium carbonate (0.29 g, 0.9 mmol) and tetrakis(triphenylphosphine)palladium(0) (34 mg, 0.03 mmol) in 1,4-dioxane (5 ml) and H2O (0.5 ml) were degassed with a stream of N2 for 10 min. The reaction mixture was then heated at reflux for 1 h. The mixture was concentrated under reduced pressure to remove the organic solvents and H2O (20 ml) was added. The organics were extracted with dichloromethane (2×50 ml) and concentrated under reduced pressure while dry loading onto silica. The resulting crude residue was purified by column chromatography on silica using 70% EtOAc in hexanes containing 1% Et3N and 1% MeOH as the eluent. The resulting material was taken up in MeOH and was poured onto a strong cation exchange cartridge and eluted with methanol. The product was then eluted with 2.0M NH3 in MeOH and evaporated to give 3-[4-(pyridin-3-yl)thien-2-yl]-7-trifluoromethylimidazo[1,2-α]pyrimidine (83 mg, 80%): δH (400 MHz, d6-DMSO) 7.46-7.53 (1H, m), 7.60 (1H, d, J 7.1), 8.18 (1H, d, J 1.5), 8.22-8.30 (1H, m), 8.26 (1H, d, J 1.5), 8.42 (1H, s), 8.56-8.60 (1H, m), 9.10 (1H, s), 10.20 (1H, d, J 7.1); m/z (ES+) 346 (M+).

Provenance & Evidence