3.2. Typical Experimental Procedure for the Synthesis of 4-Amino-N-(5-methylisoxazol-3-yl)benzenesulfonamide (4)

A mixture of N-acetylsulfanilyl chloride (1) (10 mmol), 3-amino-5-methylisoxazole (2) (10 mmol), and K₂CO₃ (5 mmol) was dissolved in acetonitrile (30 mL). The reaction mass was refluxed for 2 h to give the N-acylation intermediate (3) followed by acid hydrolysis. The progress of the reaction was monitored by using TLC. After 3 h, the reaction mass was poured into ice cold water. The obtained solid was filtered and washed with water. The crude solid was crystallized in ethanol to afford the corresponding pure product (4) and used for the further reaction without purification.