| Popis: |
Several β-ketoesters were dilithiated with an excess of lithium diisopropylamide, followed by condensation with methyl 2-(aminosulfonyl)benzoate to give intermediates that were not isolated but cyclized to 3-substituted 1,2-benzisothiazole-1,1-dioxides. In most instances involving the ester-sulfonamide, a single β-ketoester tautomer is usually formed after recrystallization from ethanol. The same dilithiated β-ketoesters generally condense less well with 1,2-benzisothiazol-3(2H)-one-1,1-dioxide (saccharin) under the same conditions to afford the same products usually in the same or lower yields. The use of N,N,N',N'-tetramethylethylenediamine during these syntheses has sometimes resulted in improved yields of products. |
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