15 g (0.034 mol) of the thus obtained 2,4,5-tris(4'-nitrophenyl)thiazole was mixed with 500 ml of N,N-dimethylformamide and 20 g of iron powder. The mixture was admixed with 10 ml of concentrated sulfuric acid and 30 ml of water. The admixture was heated to a temperature of 100° C. with thorough stirring. After 1 hour passed, the solution was neutralized with a saturated aqueous solution of sodium hydrogencarbonate with the reaction temperature kept at 100° C. to adjust the pH value thereof to 8. The reaction solution was then hot-filtered. The filtrate was poured into 3 l of ice water to produce a light yellow precipitate of 2,4,5-tris(4'-aminophenyl)thiazole which was then filtered off and dried to obtain 11.3 g (yield: 94%) of the product.
