The efficient synthesis of dialkoxyphosphoryl- and phosphonio-substituted pyridines is reported. The cationic heterocycle of N-(trifluoromethylsulfonyl)pyridinium triflate (3), or of analogous N-(trifluoromethylsulfonyl) compounds prepared from pyridine-4-phosphonium salts 5, turns out to be sufficiently activated to allow attack of P(OR)3 and PR3 nucleophiles to give the novel compounds bis(dialkoxyphosphoryl)pyridines 11 and phosphonio(dialkoxyphosphoryl)pyridines 13. For example, 13 a - d, with PO(OR)2 at the C2 and PR3 + at the C4 position, represent the first examples of an N-heteroaromatic ring substituted by both dialkoxyphosphoryl and phosphonio moieties. The structure of 13 b [PPh3 +/PO(O-i-Pr)2] was confirmed by X-ray analysis. In most cases, the intermediate 1-(trifluoromethylsulfonyl)dihydropyridines, such as 7, 8 (monosubstituted) or 10 a and b and 12 a - d (disubstituted), are sufficiently stable for isolation.
报告了二烷氧基
磷酰基和膦酰基取代的
吡啶的高效合成。N-(三
氟甲基磺酰基)
吡啶三酸酯 (3) 的阳离子杂环,或由
吡啶-4-膦盐 5 制备的类似 N-(三
氟甲基磺酰基)化合物的阳离子杂环、结果表明,这些化合物具有足够的活化性,可以受到 P(OR)3 和 PR3 亲核物的攻击,从而得到新型化合物双(二烷氧基
磷酰)
吡啶 11 和膦酰基(二烷氧基
磷酰)
吡啶 13。例如,13 a - d 在 C2 位置上具有 PO(OR)2,在 C4 位置上具有 PR3 +,是 N-杂芳香环同时被二烷氧基
磷酰和膦酰基取代的第一个实例。X 射线分析证实了 13 b [PPh3 +/PO(O-i-Pr)2] 的结构。在大多数情况下,中间体 1-(三
氟甲基磺酰基)
二氢吡啶,如 7、8(单取代)或 10 a 和 b 以及 12 a - d(二取代),都足够稳定,可以分离出来。