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

Participants

Reaction Conditions

Reaction Steps

To 3-cyclopropyl-5-hydroxy-8-methyl-1-(3-nitrophenyl)-1H,8H-pyrido[2,3-d]pyrimidine-2,4,7-trione 10 (18 g) obtained in Step 5 were added acetonitrile (180 ml), tosyl chloride 11 (11 g) and triethylamine (8 ml), and the mixture was stirred with heating under reflux at 110° C. for 1 hr. The reaction mixture was concentrated under reduced pressure. Water (100 ml) was added to the residue and the mixture was extracted with chloroform (800 ml). The organic layer was washed with brine (50 ml), dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue was recrystallized from chloroform:diethyl ether=1:5 to give toluene-4-sulfonic acid 3-cyclopropyl-8-methyl-1-(3-nitrophenyl)-2,4,7-trioxo-1,2,3,4,7,8-hexahydro-pyrido[2,3-d]pyrimidin-5-yl ester 12 (21 g, 82%) as a white solid.

Provenance & Evidence