N-Substituted formamides as nucleophiles react with in situ-generated 1,4-oxazepines from N-propargylic β-enaminones followed by spontaneous N-deformylation to deliver densely substituted 2-aminopyridines in good yields (31–88%). The formyl group is found to be a superior traceless activating group of free amines and would ultimately be removed in situ. This reaction proceeds smoothly at room temperature
A new strategy for the synthesis of pyridines from <i>N</i>-propargylic β-enaminothiones
作者:Yilmaz Kelgokmen、Metin Zora
DOI:10.1039/c8ob03180k
日期:——
A newmethod for the synthesis of 2,4,5-trisubstituted pyridines from N-propargylic β-enaminothiones is reported. β-Enaminothiones were prepared by thionation of the corresponding β-enaminones with Lawesson's reagent. When treated with diisopropylamine in DMF at room temperature, N-propargylic β-enaminothiones yielded 2,4,5-trisubstituted pyridines in moderate to high yields, along with small amounts
Base-mediated regiospecific cascade synthesis of N-(2-pyridyl)pyrroles from N-propargylic β-enaminones
作者:Jinhai Shen、Xifa Yang、Fuyuan Wang、Yue Wang、Guolin Cheng、Xiuling Cui
DOI:10.1039/c6ra08987a
日期:——
A KOH-promoted regiospecificsynthesis of polysubstituted N-(2-pyridyl)pyrroles under transition metal-free conditions has been developed. The pyrrole and pyridine rings were simultaneously installed from acyclic enaminone precursors under mild conditions and generated 1 equiv. of H2O as the sole byproduct. A series of polysubstituted N-(2-pyridyl)pyrroles were provided in up to 91% yield for 21 examples