Racemic and enantiopure 4-(piperidine-2′-yl)-pyridazines: novel synthesis of anabasine-analogues with potential nicotinic acetylcholine receptor agonist activity—a new approach via Diels–Alder reaction with inverse electron demand
作者:Astrid Stehl、Gunther Seitz、Karen Schulz
DOI:10.1016/s0040-4020(01)01236-4
日期:2002.2
A novel multistep synthesis of anabasine analogues bearing a bioisosteric pyridazine moiety instead of a pyridine nucleus in 2-position of the piperidine ring of the alkaloid is described. Starting materials are racemic 2-hydroxymethyl-piperidine, racemic pipecolic acid or (S)-(−)-piperidine-1,2-dicarboxylic-acid-1-tert-butyl ester. Key step of this synthetic approach is a Diels–Alder cycloaddition
描述了在生物碱的哌啶环的2位上带有生物等位吡啶嗪部分而不是吡啶核的鸟嘌呤类似物的新颖的多步合成。起始原料是外消旋的2-羟甲基-哌啶,外消旋的胡椒酸或(S)-(-)-哌啶-1,2-二羧酸-1-叔丁酯。这种合成方法的关键步骤是具有逆电子需求的Diels-Alder环加成工艺,利用不同的1,2,4,5-四嗪作为缺电子二烯,使用新的外消旋或对映纯的2-(2'-甲氧基乙烯基)-哌啶富电子的亲二烯体。在该[4 + 2]-环加成中,1,2,4,5-四嗪用作合成子,用于在哌啶部分的2-位引入哒嗪环。