Phosphorus oxychloride → HCID 59699571, compound

Participants

Reaction Steps

A solution of 1-benzyl-4-hydroxy-2-oxo-1,2-dihydro-[1,8]-naphthyridine-3-carboxylic acid ethyl ester (3) (0.94 g, 2.9 mmol) was heated in neat POCl3 at 90° C. for 3 h. The solution was cooled and the excess POCl3 was distilled under vacuum. The residue was suspended in water, neutralized by solid NaHCO3, and extracted by dichloromethane. The organic layer was subsequently washed by saturated NaHCO3 solution, water and brine, dried over Na2SO4, and evaporated to yield 0.9 g (98%) of 1-benzyl-4-chloro-2-oxo-1,2-dihydro-[1,8]-naphthyridine-3-carboxylic acid ethyl ester (4) as white solids. MP: 109° C.; 1H-NMR (DMSO-d6): δ 1.31 (t, J=6.9 Hz, 3H), 4.37 (q, J=6.9 Hz, 2H), 5.62 (s, 2H), 7.27 (m, 5H), 7.51 (dd, J=4.7, 8.0 Hz, 1H), 8.46 (dd, J=1.5, 7.5 Hz, 1H), 8.80 (dd, J=1.5, 7.5 Hz, 1H); EIMS: 343 (M+1), 365 (M+23).

Provenance & Evidence