6-Benzyloxy-2,5-dioxo-1,2,3,5-tetrahydro-imidazo[1,2-a]pyrimidine-7-carboxylic acid ethyl ester → 6-Hydroxy-2,5-dioxo-1,2,3,5-tetrahydro-imidazo[1,2-a]pyrimidine-7-carboxylic acid ethyl ester

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Reaction Steps

A solution of intermediate 4, 6-benzyloxy-2,5-dioxo-1,2,3,5-tetrahydro-imidazo[1,2-a]pyrimidine-7-carboxylic acid ethyl ester, (0.770 g, 2.34 mmol) in trifluoroacetic acid (20 ml) was stirred at 25° C. for 1 h. The solvent was then evaporated under reduced pressure and residual trifluoroacetic acid removed by azeotropic distillation with toluene in vacuo. Acetic acid (5 ml) was added and the mixture subjected to azeotropic distillation with toluene in vacuo to remove solvent and residual acid. Recrystallization of the solid residue from ethyl acetate gave 0.497 g (88% yield) of the title ester as white crystals; mp 265° C. (dec).

Provenance & Evidence