利用5-芳基偶氮-2,3,6-三取代吡啶的[4 + 1]环加成反应合成2-芳基-3-二甲基氨基吡唑并-[3,4- c ]吡啶的策略
摘要:
为了探讨最近发现的基于[4 + 1]环加成反应的吡唑并[3,4- c ]吡啶衍生物的制备方法的可行性和一般性,该策略是一系列5-芳基偶氮-2,3,6-的成员通过3-氧代-2-芳基肼基丙醛与3-氧代-3-苯基丙腈的反应制备三取代的吡啶。结果表明3-氧代-3-苯基丙腈与底物反应,该底物在芳基hydr部分的N-芳基环上不包含吸电子取代基,从而有效地产生6-芳基-2-苯基-5-芳基氮杂腈。相反,在3-氧代-2-芳基肼基丙醛的反应中生成2-氨基-6-芳基-5-芳基偶氮-3-苯甲酰基吡啶,其在N上含有吸电子取代基。-芳基部分。以预测的方式,6-芳基-2-苯基-5-芳基氮杂腈与二甲基甲酰胺二甲基乙缩醛(DMF-DMA)进行平滑反应,从而导致形成一类新的2-芳基-3-二甲基氨基吡唑并[3,4- c ]吡啶。此过程的机理涉及[4 + 1]环加成反应,该反应通过将由DMF-DMA生成的二甲氨基)甲氧基卡宾的初
Reactions under Pressure: Synthesis of Functionally Substituted Arylhydrazonal Derivatives as Precursors of Novel Pyridazines and Nicotinates
摘要:
Q-tube assisted multicomponent synthesis of novel arylhydrazonals, pyridazines and nicotinates has been explored. The target molecules have been prepared via one pot reaction of arylhydrazonals with activated methylene nitriles in either ethanolic piperidine, dimethyl acetylene dicarboxylate (DMAD), 1,4-diazobicyclo[2.2.2]octane (DABCO), or Ph3P under pressure. Such conditions make reaction time much shorter and yields higher as compared with those conducted under conventional conditions. The structures of products have been determined by X-ray crystallography and spectroscopic methods.