Triethylamine → 4-Pyridin-2-ylethynyl-quinoline-2-carboxylic Acid Ethyl Ester

Participants

Reaction Conditions

Reaction Steps

A mixture of ethyl 4-bromoquinoline-2-carboxylate (2.80 g, 10.0 mmol, J. Org. Chem. 1947, 12, 456), triethylamine (1.7 mL, 12 mmol), bis(triphenylphosphine)-palladium(II)chloride (0.561 g, 0.80 mmol), CuI (0.114 g, 0.60 mmol), and 2-ethynylpyridine (1.11 g, 10.8 mmol) in CH3CN (80 mL) is heated at 75-80° C. for 18 h in a sealed tube. Additional triethylamine (0.85 ml, 6.1 mmol), bis(triphenylphosphine)palladium (II) chloride (0.23 g, 0.40 mmol), and CuI (0.055 g, 0.29 mmol) is added and the mixture heated for an additional 18 h. The mixture is concentrated in vacuo and partitioned between water and chloroform. The chloroform extracts are washed with brine and evaporated. The residue is chromatographed on SiO2 (50% ethyl acetate/hexanes) to yield 1.52 g (50%) of a yellow solid. Precipitation from ethyl acetate gave the title compound as yellow crystals: mp 129-131° C.; MS ES+ m/e 303 (M+1).

Provenance & Evidence