Isothiazole ring skeleton was formed by the treatment of substituted 2-alkylthio-3-acyl-4-quinolinone with O-(mesitylenesulfonyl)hydroxylamine(MSH). A mixture of alkyl transferred 3-methyl-9-alkyl-4,9-dihydroisothiazolo[5,4-b]quinolin-4-one as a major product and dealkylated 3-methyl-4,9-dihydroisothiazolo[5,4-b]quinolin-4-one as a minor product was obtained from unsubstituted 2-alkylthio-3-acyl-4-quinolinone in the presence of K2CO3. When 2 equivalents of MSH were used in the absence of K2CO3 only dealkylated product was obtained in quantitative yield.
O-(mesitylenesulfonyl)hydroxylamine(MSH) 处理取代的 2-烷
硫基-3-乙酰基-4-
喹啉酮,形成
异噻唑环骨架。 在 K2CO3 的存在下,从未取代的 2-烷
硫基-3-乙酰基-4-
喹啉酮中得到了以烷基转移的 3-甲基-9-烷基-4,9-二氢
异噻唑并[5,4-b]
喹啉-4-酮为主要产物,以脱烷基的 3-甲基-4,9-二氢
异噻唑并[5,4-b]
喹啉-4-酮为次要产物的混合物。在没有 K2CO3 的情况下,使用 2 个等量的 MSH 时,只能得到定量的脱烷基产物。