Regioselective homolytic substitution of benzo[c][2,7]naphthyridines

详细信息    查看全文

• 作者：Alois Plodek ; Stephan Raeder ; Franz Bracher<sup> ; sup><sup>Franz.Bracher@cup.uni-muenchen.desup>
• 关键词：Benzo[c][2 ; 7]naphthyridines ; Homolytic substitution ; Alkaloids ; Pyridoacridines
• 刊名：Tetrahedron
• 出版年：2012
• 出版时间：17 June, 2012
• 年：2012
• 卷：68
• 期：24
• 页码：4693-4700
• 全文大小：319 K

文摘

Benzo[c][2,7]naphthyridines bearing electron-withdrawing substituents (bromo, acetyl) at C-4 undergo regioselective homolytic substitutions at C-5 with nucleophilic 1,3,5-trioxanyl and ethoxycarbonyl radicals under Minisci conditions. Surprisingly, mainly 5,6-dihydro derivatives are formed in these reactions. Rearomatization with manganese dioxide leads to 4,5-disubstituted benzo[c][2,7]naphthyridines, which should be attractive building blocks for the synthesis of pyridoacridine alkaloids. Homolytic methylation at C-5 takes place with methyl radicals generated from acetic acid and acetaldehyde, respectively.