Bromine → HCID 87650644, compound

Participants

Reaction Steps

To a solution of 3-benzyloxy-4-oxo-4H-pyran-2-carboxylic acid 3-chlorobenzylamide (5.13 g) obtained in Example 10, Step 1 in chloroform (100 ml) was added a solution of bromine (1.5 ml) in chloroform (50 ml) and the mixture was stirred with heating under reflux for 2 hr. A solution of bromine in chloroform (1.0 ml) was added, and after stirring with heating for 16 hr, the solvent was evaporated. Toluene was added to the residue and the mixture was concentrated, which operations were performed twice to give a crude product of 5-bromo-3-hydroxy-4-oxo-4H-pyran-2-carboxylic acid 3-chlorobenzylamide. The obtained crude product was dissolved in dimethylformamide (50 ml), and potassium carbonate (3.87 g) and benzyl bromide (2.75 ml) were added thereto. The reaction mixture was stirred at room temperature for 1 hr. Water (100 ml) and 1N aqueous hydrochloric acid (50 ml) were added to the reaction mixture and the mixture was extracted twice with ethyl acetate (200 ml each). The ethyl acetate layer was washed, dried, concentrated and purified by silica gel column chromatography (ethyl acetate:hexane=1:3) to give 3-benzyloxy-5-bromo-4-oxo-4H-pyran-2-carboxylic acid 3-chlorobenzylamide (3.31 g).

Provenance & Evidence