1-Benzyl-3-bromo-5-chloro-2-pyridone → 4-(1-benzyl-5-chloro-2-oxo-3-pyridinyl)-N-[(1,1-dimethylethoxy)carbonyl]-L-phenylalanine methyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of 1-benzyl-3-bromo-5-chloro-2-pyridone (296 mg, 0.98 mmol) and N-[(1,1-dimethylethoxy)carbonyl]-4-[(tributyl)stannyl]-L-phenylalanine methyl ester (560 mg, 0.99 mmol) in DMF (15 mL) was deoxygenated by alternately freezing the mixture in a liquid nitrogen bath under vacuum and thawing under argon (3×). Bis(triphenylphosphine)palladium dichloride (80 mg, 0.11 mmol) was added and the mixture was heated to 90° C. for 4 hr as the mixture turned dark. An additional 60 mg of the catalyst was added and heating continued for 2 hr. The mixture was allowed to cool, was diluted with dichloromethane, and was filtered through a pad of celite. The filtrate was evaporated to dryness and the residue was chromatographed over 150 g of silica gel eluting with 1:2 ethyl acetate:hexane to give 4-(1-benzyl-5-chloro-2-oxo-3-pyridinyl)-N-[(1,1-dimethylethoxy)carbonyl]-L-phenylalanine methyl ester (255 mg, 52%). LMS-Electrospray: m/z 1015 (2M+Na) (4 Cl) 519 (M+Na) 514 (M+NH4) 497 (M+H).

Provenance & Evidence