Sodium Carbonate → 5-Oxazol-5-yl-pyrazine-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

Aqueous Na2CO3 solution (2 M, 14.5 mL) and [1,1′-bis(diphenylphosphino)-ferrocene]dichloropalladium dichloromethane complex (950 mg) are added to a mixture of 5-chloropyrazine-2-carboxylic acid methyl ester (2.00 g) and 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2-[tris(isopropyl)silyl]-oxazole (4.70 g) in N,N-dimethylformamide (20 mL) under an argon atmosphere. The reaction mixture is stirred over night at 80° C. After cooling to room temperature, the solvents are evaporated, the residue is mixed water and acidified with 4 N hydrochloric acid (12 mL). A precipitate is formed upon addition of ethyl acetate, which is filtered off, washed with ethyl acetate and methanol, and dried. LC (method 7): tR=0.46 min; Mass spectrum (ESI−): m/z=190 [M−H]−.

Provenance & Evidence