2-(1-Alkenyl)- and 2-aryl-substituted four-membered cyclic nitrones as precursors for 2,3,4-substituted pyridines and quinolines
作者:W. Verboom、P.J.S.S. Van Eijk、P.O.M. Conti、D.N. Reinhoudt
DOI:10.1016/s0040-4020(01)80139-3
日期:1989.1
Reaction of the 2-(1-alkenyl)-substituted four-membered cyclic nitrones 3 with KOtBu gave the corresponding α,β-γ,δ-unsaturated oximes 6 which were converted into the substituted pyridines 9, either by azeotropic removal of water in refluxing benzene or by reactfon in a 1:1 mixture of acetic anhydride and acetic acid at room temperature. Treatment of pyridine 9c with boron tribromide afforded the benzopyrano[4
2-(1-烯基)-取代的四元环硝酮3与KOtBu的反应得到相应的α,β-γ,δ-不饱和肟6,它们通过在水中共沸除去水而转化为取代的吡啶9。在室温下,回流苯或在乙酸酐和乙酸的1:1混合物中反应。用三溴化硼处理吡啶9c,得到苯并吡喃并[4,3-c]吡啶衍生物10。2-芳基取代的四元环硝酮4与乙酰氯的反应产生了O-乙酰化的肟12,其在辐射下环化为2,3,4-取代的喹啉14。