Unusual Ambident Behavior and Novel Ring Transformation of Oxazolo[3,2-a]pyridinium Salts
作者:Eugene V. Babaev、Andrey V. Efimov、Dmitriy A. Maiboroda、Karl Jug
DOI:10.1002/(sici)1099-0690(199801)1998:1<193::aid-ejoc193>3.0.co;2-6
日期:1998.1
2-Aryloxazolo[3,2-a]pyridinium perchlorate, 1a, and its 5-methyl homologue, 1b, undergo quite different ring transformations when reacting with piperidine. For 1a the opening of the pyridine fragment occurs with formation of the isomeric aminobutadienes 2 [with (1E,3E)-configuration] or 3 [(1E,3Z)-isomer], depending on the temperature, whereas 1b undergoes an unexpected recyclization of the oxazolium
当与哌啶反应时,2-Aryloxazolo [3,2- a ]高氯酸吡啶鎓1a和它的5-甲基同系物1b经历完全不同的环转化。对于1a,根据温度的不同,吡啶片段的打开会随着异构体氨基丁二烯2 [具有(1 E,3 E)-构型]或3 [(1 E,3 Z)-异构体]的形成而发生,而1b经历恶唑环意外的涉及甲基的环化反应,形成5-氨基吲哚嗪4。1a和1b与碱反应时会经历5元环的开环。这些结果通过量子化学SINDO1计算得到解释,该计算给出了具有NMe 2和HO基团的异构体C5-和C8a加合物的能量。