Ethyl chloroformate → 2-Methoxy-4-methyl-6-(3-nitrophenyl)-1,5(6H)-pyrimidinedicarboxylic acid, diethyl ester

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Reaction Steps

A solution of 1,4-dihydro-2-methoxy-6-methyl-4-(3-nitrophenyl)-5-pyrimidinecarboxylic acid, ethyl ester (3.19 g, 10.0 mmoles) in dry dichloromethane (15 ml) and pyridine (4 ml) was cooled to 0° C. and treated dropwise with ethyl chloroformate (1.2 ml, 12.0 mmoles) under argon. After the addition was completed, the cooling bath was removed and the reaction was allowed to stir at room temperature for 1 hour. It was then diluted with ethyl acetate and the resulting solution was washed with water, sodium bicarbonate and brine. After drying over anhydrous magnesium sulfate, the solvent was evaporated. The residue was coevaporated with toluene to remove residual pyridine. The colorless solid obtained was subjected to high vacuum and used in the next reaction without further purification (3.81 g). For analytical purposes, a small amount of the compound was recrystallized from ether-hexanes to provide colorless solid, melting point 61.5°-64.5° C.

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