A process for producing 1,2-benzisoxazole-3-methanesulfonamide without isolation of intermediates in solid form, which comprises using 4-hydroxycoumarin as a starting compound, and water and 1,2-dichloroethane as solvents； and an industrially useful process for producing 1,2-benzisoxazole-3-acetic acid, which comprises reacting 4-hydroxycoumarin and hydroxylamine in water.所揭示者為一種在無需分離固態中間產物的情況下，以4-羥基香豆素作為起始化合物並以水及1,2-二氯乙烷作為溶劑，來合成1,2-苯並異噁唑-3-甲烷磺醯胺的方法；及一種1,2-苯並異噁唑-3-乙酸之產業有用的製備方法，其係藉由4-羥基香豆素與羥基胺在水中反應而得。
