Methyl Isocyanate → 2,4(1H,3H)-Pyrimidinedione, dihydro-1-(2,4-dichlorophenyl)-3-methyl-

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Reaction Steps

At first, 7.44 g (0.03 moles) of N-(2,4-dichlorophenyl)-β-alanine methyl ester was dissolved in 150 ml of tetrahydrofuran (THF), and 19.2 ml (0.03 moles) of n-butyl lithium was added thereto at -78° C. Several minutes thereafter, 5.4 ml (0.045 moles) of methyl isocyanate was added thereto. The mixture was stirred at the same temperature for one hour, a saturated aqueous ammonium chloride solution was added thereto, and the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with water and with a saturated aqueous sodium chloride solution, and dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography and recrystallized from toluene, whereby 1.32 g of the desired compound was obtained as colorless prism crystals having a melting point of 154°-157° C. (yield: 16.1%).

Provenance & Evidence