Then, 4.32 g (0.01 mol) of 2,4,5-tris(4-nitrophenyl)oxazole was mixed with 200 ml of N,N-dimethylformamide and 8 g of an iron powder (reduced iron available from Wako Pure Chemical Industries, Ltd.). To the resulting mixture, 4 ml of concentrated hydrochloric acid and 12 ml of water were added, and the mixture was heated to 100° C. while stirring well. After reacting for 1 hour, the reacting solution was neutralized to pH: 8 with a saturated aqueous solution of sodium carbonate, and while maintained at 100° C., it was filtered in a heated state. The filtrate was poured into 1 l of iced water. The white precipitate formed of 2,4,5-tris(4-aminophenyl)oxazole was filtered off and dried. Yield: 3.27 g (96%).
