反应详情

200 g of 7-nitro-4-hydroxy-1,2-benzisothiazole, 260 g of benzyl bromide and 210 g of potassium carbonate in 2.5 l of acetone are refluxed for 12 hours. The entire mixture is then concentrated to one liter under reduced pressure, the residue is poured into a threefold amount of water and the batch is repeatedly extracted with methylene chloride. The combined organic phases are dried over magnesium sulfate and freed from solvent under reduced pressure. The crude product is recrystallized from a mixture of methanol and tetrahydrofuran. 200 g (70% of theory) of 7-nitro-4-benzyloxy-1,2-benzisothiazole of melting point 158°-160° C. are obtained.

1. concentrationThe entire mixture is then concentrated to one liter under reduced pressure
2. additionthe residue is poured into a threefold amount of water
3. extractionthe batch is repeatedly extracted with methylene chloride
4. dry with materialThe combined organic phases are dried over magnesium sulfate
5. customThe crude product is recrystallized from a mixture of methanol and tetrahydrofuran