Optimisation of substitution at the 2- and 5- positions of 3,4-dialkoxythiophenes via the Mannich reaction: the influences of steric crowding, electrophile reactivity and temperature
作者:Joan Halfpenny、Phillip B. Rooney、Zachary S. Sloman
DOI:10.1039/b105476g
日期:2001.10.11
via the Mannich reaction with secondary amines. These reactions surprisingly gave the bis-Mannich bases substituted at the 2- and 5-positions as well as the expected mono-Mannich bases substituted at the 2-position. Conditions were optimised to give symmetrical bis-2,5-Mannich bases in one step and asymmetrical bis-2,5-Mannich bases in two steps. Several bis(thien-2-ylmethyl)amines derived from 3,4-dialkoxythiophenes
已经合成了许多3,4-二烷氧基噻吩化合物,并通过Mannich反应与仲胺。这些反应令人惊讶地给出了在2-和5-位被取代的双-曼尼希碱基以及在2-位被取代的预期的单-曼尼希碱基。优化条件,一步得到对称的bis-2,5-Mannich碱基,两步得到不对称的bis-2,5-Mannich碱基。报道了衍生自3,4-二烷氧基噻吩的几种双(噻吩-2-基甲基)胺,它们的合成在正常和高稀释条件下进行。一些合成还提供了(噻吩-2-基甲基)胺低聚物。通过曼尼希反应在5-位进一步取代双(噻吩-2-基甲基)胺也被证明是成功的。讨论了影响产量和替代模式的因素,以及空间需求的分子模型。