Cesium carbonate → HCID 69269138, compound

Participants

Reaction Conditions

Reaction Steps

Into a 100 mL, 3 neck round bottom flask equipped with a reflux condenser, magnetic stirrer and nitrogen inlet is added 350 mg (1.03 mmol, 1.0 equiv.) of 8-Bromo-6-ethoxy-4-oxo-4H-chromene-2-carboxylic acid ethyl ester (Reference Example 23b), 18.9 mg (0.02 mmol, 0.02 equiv.) of tris dibenzylidineacetone dipalladium, 77 mg (0.123 mmol, 0.12 equiv.) of racemic 2,2′-bis(diphenylphosphino)-1,1′-binapthyl and 1 g of 4 A molecular sieves and 60 mL of dry toluene. To the stirred suspension is then added 113 mg, 1255 μL, (1.13 mmol, 1.1 equiv.) of 1-methylpiperazine, followed by 470 mg (1.44 mmol, 1.4 equiv.) of cesium carbonate. The mixture is then heated to 80° C. for 3 days. At the end of this time completion was monitored by LC/MS analysis of an aliquot. When the reaction was determined to be complete it was cooled to room temperature then filtered through a plug of diatomaceous earth, with toluene washing to remove solid by products. Purification by flash chromatography, using a gradient of 5 to 40% methanol in methylene chloride as eluent, yielded 350 mg (75%) of the desired product as a yellow solid. Mass Spec.: calc. for [C19H24N2O5+H]+ Theor. m/z=361; Obs.=361.

Provenance & Evidence