Synthesis of Functionalized Pyridazin-3(2H)-ones via Nucleophilic Substitution of Hydrogen (SNH)

详细信息    查看全文

• 作者：Tom Verhelst ; Stefan Verbeeck ; Oxana Ryabtsova ; Stefaan Depraetere ; Bert U. W. Maes
• 刊名：Organic Letters
• 出版年：2011
• 出版时间：January 21, 2011
• 年：2011
• 卷：13
• 期：2
• 页码：272-275
• 全文大小：165K
• 年卷期：v.13,no.2(January 21, 2011)
• ISSN：1523-7052

文摘

Reaction of 2-benzyl-5-halopyridazin-3(2H)-ones (3) with Grignard reagents followed by quenching with electrophiles unexpectedly yielded 4,5-disubstituted pyridazin-3(2H)-ones instead of 5-substituted pyridazin-3(2H)-ones. These reactions represent the first examples of cine substitution in which the anionic 蟽^H-adduct is quenched by electrophiles (other than a proton) before elimination takes place. Insight into the reaction mechanism led to the direct transformation of 2-benzylpyridazin-3(2H)-one (7) and 2-benzyl-6-chloropyridazin-3(2H)-one (9) into the corresponding C-4 alkyl and aryl derivatives (when Br₂ was used as the electrophile).