A synthesis of 2-substituted oxazolo[3,2-a]pyridiniumsalts is described. The appropriate 2-(4-ethoxybutyryl)-oxazoles are treated with hydrobromic acid and then cyclised and aromatised by boiling acetic anhydride. Attempts to prepare 2-substituted oxazoles suitable for the synthesis of the parent oxazolopyridinium ion have been unsuccessful. Catalytic reduction of two oxazolopyridinium salts leads
描述了2-取代的恶唑并[3,2- a ]吡啶鎓盐的合成。用氢溴酸处理适当的2-(4-乙氧基丁酰基)-恶唑,然后环化并通过沸腾乙酸酐使其芳香化。尝试制备适合于母体恶唑吡啶鎓离子合成的2-取代的恶唑是失败的。两种恶唑并吡啶鎓盐的催化还原导致开环,得到N-取代的2-哌啶酮。
A self-[3+2] annulation reaction of pyridinium salts has been developed for the synthesis of N-indolizine-substituted pyridine-2(1H)-ones. This protocol was carried out under mild reaction conditions without any precious catalysts in generally moderate to good yields. Additionally, a plausible mechanism for the transformation was proposed.
吡啶鎓盐的自[3+2] 环化反应已被开发用于合成N-中氮茚取代的吡啶-2(1 H )-酮。该方案是在温和的反应条件下进行的,没有任何贵重的催化剂,产率通常适中。此外,还提出了一种合理的转化机制。