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EXAMPLE 3. 2-amino-4,5-dicyano-1-n-pentyloxycarbonylimidazole 2 g of 2-amino-4,5-dicyanoimidazole was dissolved in 20 ml of acetonitrile, 1.6 g of triethylamine was added to said solution and further 2.3 g of n-amyl chloroformate was added dropwise to it at a room temperature. The resulting solution was refluxed during 30 minutes, and white crystal was separated out when the reaction mixture was poured into ice-water. After recrystallizing the crude product from methanol, 3.1 g of the purified compound having a melting point of 166 to 169C was obtained as needles (Yield rate: 83%).