General procedure for the synthesis of 3-methylisoxazol-4-amine from tert-butyl (3-methylisoxazol-4-yl)carbamate: tert-butyl (3-methylisoxazol-4-yl)carbamate (150 mg, 0.75 mmol) was dissolved in a mixture of trifluoroacetic acid (TFA) and dichloromethane (DCM) (10 mL, v/v 1:1), and the reaction was stirred at room temperature for 1 The reaction was stirred for 1 hour at room temperature. After the reaction was completed, the reaction solution was concentrated and the resulting residue was dissolved in dichloromethane (20 mL) and neutralized by adding solid potassium carbonate (K2CO3, 1 g). The solid was removed by filtration and the filtrate was concentrated to give the crude 3-methylisoxazol-4-amine (96 mg, yield: 93%), which could be used in the next reaction without further purification.
