Synthesis and base-mediated rearrangement of 3-acetyl-2-methyl-3,4-dihydro-2H-1,2,3-benzothiadiazine 1,1-dioxides

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• 作者：Má ; rta Porcs-Makkay ; Imre Gyűjtő ; Gyula Simig ; Balá ; zs Volk ; ^{volk.balazs@egis.hu}
• 关键词：Rearrangement ; Ring contraction ; Acylation ; Reduction ; Reaction mechanism
• 刊名：Tetrahedron
• 出版年：2016
• 出版时间：22 December 2016
• 年：2016
• 卷：72
• 期：51
• 页码：8463-8469
• 全文大小：800 K
• 卷排序：72

文摘

In continuation of our studies on the acetylation and alkylation reactions of 3,4-dihydro-2H-1,2,3-benzothiadiazine 1,1-dioxides, a 3-acetyl-2-methyl derivative was synthesized. Attempted reduction of the 3-acetyl moiety to an ethyl group with LiAlH4 led surprisingly to the corresponding 2,3-dihydro-1,2-benzisothiazol 1,1-dioxide, a ring-contracted product. The possible mechanisms of this new, base-mediated rearrangement reaction are discussed. The reaction conditions were optimized by using various bases, and the rearrangement reaction was extended to compounds exhibiting various substituents at the 4-position of the benzothiadiazine ring system.