Pyridinethiones XIV.<sup>1</sup>Reactions of 2- and 4-Alkylthiopyridines; Synthesis of 1,6- and 2,7-Naphthyridines<i>via</i>2-Methylene-1,2-dihydro- and 4-Methylene-1,4-dihydropyridines
作者:Fahmy Mekhail Asaad、Jan Becher、Jørgen Møller、Karikath Sukumar Varma
DOI:10.1055/s-1987-27927
日期:——
2,4-Bismethylthiopyridinium iodides prepared from 2(1 H)-pyridinethiones react regioselectively with active methylene compounds, preferentially at the 4-position, yielding 4-alkylidene-1,4-dihydropyridines. The corresponding 4-benzylthio-2-methylthiopyridinium iodide gave a mixture of 2-alkylidene-1,2-dihydro- and 4-alkylidene-1,4-dihydropyridines. By treatment with phosphoric acid, the resulting new 3-acetyl-2-alkyliden-1,2-dihydro- and 4-alkylidene-1,4-dihydropyridines yielded 1,6- and 2,7-naphthyridines, respectively.
2,4-双甲基硫代吡啶鎓碘化物由2(1 H)-吡啶硫酮制备,与活性亚甲基化合物进行位点选择性反应,优先在4位上反应,生成4-亚甲基-1,4-二氢吡啶。相应的4-苄硫基-2-甲硫基吡啶鎓碘化物生成2-亚甲基-1,2-二氢吡啶和4-亚甲基-1,4-二氢吡啶的混合物。通过磷酸处理,生成新的3-乙酰基-2-亚甲基-1,2-二氢吡啶和4-亚甲基-1,4-二氢吡啶,分别生成1,6-和2,7-萘啶。