Carbamimidic acid, methyl ester, sulfate (1:1) → 1,4-Dihydro-2-methoxy-6-methyl-4-(3-nitrophenyl)-5-pyrimidinecarboxylic acid, ethyl ester

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Reaction Steps

A reaction mixture containing 2-[(3-nitrophenyl)methylene]-3-oxobutanoic acid, ethyl ester (2.62 g, 10.0 mmole), 2-methylpseudourea sulfate (1.72 g, 10.0 mmole), and sodium bicarbonate (2.52 g, 30.0 mmole) in dimethylformamide (10 ml) was heated at 65°-70° C. for 16 hours. The reaction mixture was allowed to cool to room temperature, diluted with ethyl acetate, and filtered. The filtrate was washed with water and brine, and then dried over anhydrous magnesium sulfate. Evaporation of the solvent gave a yellow oil which was purified by flash chromatography (5% ethyl acetate in dichloromethane). The resulting foam was crystallized from isopropyl ether/hexanes to provide 2.41 g of 1,4-dihydro-2-methoxy-6-methyl-4-(3-nitrophenyl)-5-pyrimidinecarboxylic acid, ethyl ester as a colorless crystalline product; melting point 103.5°-105° C. TLC (silica gel; ethyl acetate: hexanes 50:50) Rf =0.31

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