Acetonitrile → Toluene-4-sulfonic acid 1-(4-bromo-phenyl)-3-cyclopropyl-6,8-dimethyl-2,4,7-trioxo-1,2,3,4,7,8-hexahydro-pyrido[2,3-d]pyrimidin-5-yl ester

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Reaction Steps

To 1-(4-bromo-phenyl)-3-cyclopropyl-5-hydroxy-6,8-dimethyl-1H,8H-pyrido[2,3-d]pyrimidine-2,4,7-trione 38 (400 mg) obtained in Step 5 was added acetonitrile (8.0 ml), tosyl chloride 11 (458 mg) and triethylamine (0.34 ml) were added under a nitrogen atmosphere, and the mixture was stirred under reflux for 30 hrs. After allowing to cool to room temperature, the mixture was concentrated under reduced pressure. The residue was purified by column chromatography (chloroform:acetone=25:1→20:1) to give toluene-4-sulfonic acid 1-(4-bromo-phenyl)-3-cyclopropyl-6,8-dimethyl-2,4,7-trioxo-1,2,3,4,7,8-hexahydro-pyrido[2,3-d]pyrimidin-5-yl ester 39 (407 mg, yield 74%) as ocher crystals.

Provenance & Evidence