Dichloromethane → HCID 22326934, compound

Participants

Reaction Conditions

Reaction Steps

To 7-bromo--benzo[b]thiophene (5.28 g, 24.7 mmol) was added pyridine-4-boronic acid (2.734 g, 22.24 mmol), K3PO4 (12.0 g, 56.5 mmol), 37.5 mL of 1,4-dioxane and 3.8 mL of water. The mixture was placed under vacuum for several minutes and flushed with nitrogen. This was repeated 5 times. Pd(dppf)Cl2.CH2Cl2 (0.909 g, 1.11 mmol), PdCl2 (0.1994 g, 1.124 mmol) and 1,1″-bis(diphenylphosphino)ferrocene (0.6234 g, 1.124 mmol) were purged in the same way using high vacuum. The catalyst was added to the reaction flask, which was purged again 3 times. The mixture was stirred at 80° C. under nitrogen. After 1 day TLC showed much starting material remained. Additional K3PO4 (2.3 g, 10.8 mmol) was added after purging. Stirring at 80° C. under nitrogen was continued for 12 to 14 hours and then at room temperature till the next day. The mixture was partitioned between water and ethyl acetate, filtered through Celite and the layers separated. The organic layer was concentrated in vacuum. The residue was redissolved in ethyl acetate, washed with water and dried over magnesium sulfate. Concentration in vacuum gave 6.06 g of dark oil. This was eluted from silica gel with a gradient of hexane and ethyl acetate to give 2.43 g of the title compound as a tan oil that crystallizes slowly, (m.p.71-72° C.).

Provenance & Evidence