2-Dicyclohexylphosphino-2',6'-dimethoxybiphenyl → HCID 90272040, compound

Participants

Reaction Conditions

Reaction Steps

Another 2-neck 50 mL round bottom flask was charged with palladium(II) acetate (67.4 mg, 0.3 mmol) and 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (246 mg, 0.6 mmol) at room temperature under a nitrogen atmosphere. Then, it was dissolved in tetrahydrofuran (2 mL). After 5 minutes, a solution of ethyl 1-(biphenyl-2-ylmethyl)-7-bromo-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate (695 mg, 1.5 mmol) in tetrahydrofuran (5 mL) was added, followed by the above prepared white suspension of methylzincchloride magnesium in tetrahydrofuran. The resulting brown suspension was heated to 55° C. and stirred for 15 h at which time it turned to a black solution and LCMS analysis indicated the absence of starting material. Then, the reaction mixture was quenched with saturated ammonium chloride solution and the organic compound was extracted into ethylacetate (3×70 mL). The combined extracts were washed with water and brine solution, and dried over anhydrous MgSO4. Filtration and concentration gave the crude product (1.2 g) which was purified using an ISCO (80 g) column chromatography, eluting with ethyl acetate in hexanes (0 to 100%) and then 10% methanol and dichloromethane. The desired fractions were combined and the solvent was removed under vacuum to obtain ethyl 1-(biphenyl-2-ylmethyl)-7-methyl-4-oxo-1,4-dihydro-1,5-naphthyridine-3-carboxylate (20) (80 mg, 13.4% yield) as a yellow solid.

Provenance & Evidence