Trifluoroacetic acid → Ethyl 6-(4-fluorobenzyl)-4-hydroxy-5-oxo-5,6,7,8-tetrahydro-2,6-naphthyridine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

In a heavy walled round bottom flask with screw top were combined ethyl 5-butoxy-1,3-oxazole-2-carboxylate (2.53 g, 11.88 mmol) and 1-(4-fluorobenzyl)-5,6-dihydropyridin-2-(1H)-one (1.22 g, 5.94 mmol; see Example 1, Step 3) and trifluoroacetic acid (0.46 mL, 5.94 mmol). The vessel was sealed and placed in an oil bath heated to 130° C. The reaction mixture was stirred for 3 days. The dark brown reaction mixture was cooled and a crystalline precipitate formed. The mixture was diluted with ether and the solids collected by filtration and washed with ether to give the product as tan shiny plates. Further product can be obtained by evaporating the mother liquor, adding more trifluoroacetic acid and re-heating the mixture.

Provenance & Evidence