Triethylamine → HCID 131731313, compound

Participants

Reaction Conditions

Reaction Steps

Synthesis of methyl 6-methoxy-5-(4-methyl-1H-imidazol-1-yl)pyridine-2-carboxylate (C2). To a solution of the known 6-bromo-2-methoxy-3-(4-methyl-1H-imidazol-1-yl)pyridine (C1, T. Kimura et al., U.S. Pat. Appl. Publ. (2009), US 20090062529 A1) (44.2 g, 165 mmol) in methanol (165 mL) was added triethylamine (46 mL, 330 mmol) and [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II), dichloromethane complex (6.7 g, 8.24 mmol). The mixture was degassed several times with nitrogen. The reaction was heated to 70° C. under CO atmosphere (3 bar) in a Parr apparatus. After 30 minutes, the pressure dropped to 0.5 bar; additional CO was added until the pressure stayed constant for a period of 30 minutes. The mixture was allowed to cool to room temperature and filtered through a pad of Celite. The Celite pad was washed twice with methanol and the combined filtrates were concentrated under reduced pressure. The residue (88 g) was dissolved in ethyl acetate (1 L) and water (700 mL), and the layers were separated. The organic layer was washed with water (200 mL), and the aqueous layer was extracted with ethyl acetate (500 mL). The combined organic layers were dried over magnesium sulfate, filtered and concentrated to provide the title compound. Yield: 42.6 g, 175 mmol, quantitative.

Provenance & Evidence