General procedure for the synthesis of 4-(5-oxazolyl)aniline from 5-(4-nitrophenyl)oxazole: To a solution of ethanol (10 mL) containing 5-(4-nitrophenyl)oxazole (500 mg, 2.6 mmol) was added powdered tin (620 mg, 5.2 mmol), followed by the slow dropwise addition of concentrated hydrochloric acid (1 mL). The reaction mixture was stirred at room temperature for 2 hours. After completion of the reaction, the mixture was filtered and the filtrate was evaporated to dryness. The resulting residue was diluted with distilled water (10 mL) and alkalized to pH neutral with saturated sodium bicarbonate solution. Subsequently, the aqueous phase was extracted with ethyl acetate. The organic layer was separated, washed with distilled water, dried over anhydrous sodium sulfate and finally concentrated to dryness to give 4-(5-oxazolyl)aniline (380 mg, 90% yield) as a solid product.
