Synthesis of 2<i>H</i>-chromeno[4,3-<i>b</i>]pyridine-2,5(1<i>H</i>)-diones and related heterocycles<i>via</i>the erlenmeyer-ploechl reaction
作者:Ivo Christov Ivanov、Toma Nikolaev Glasnov、Dieter Heber
DOI:10.1002/jhet.5570420517
日期:2005.7
no[4,3-b]pyridine-2,5-diones 4a-j were synthesized from 4-alkylamino-coumarin-3-carbaldehydes 1 and 5(4H)-oxazolinones (azalactones) derived from N-acetylglycine (2a) and hippuric acid (2b). The intermediates 3 (3j isolated only) underwent spontaneous recyclization via opening of the azalactone and successive formation of the fused 2-pyridones 4. Attempts to synthesize the selected 2H-chromeno[3,4-f]-1
由4-烷基氨基香豆素-3-甲醛1和5(4 H)-合成1,2-二氢-5 H- [1]苯并吡喃并[4,3 - b ]吡啶-2,5-二酮4a-j。由N-乙酰基甘氨酸(2a)和马尿酸(2b)衍生而来的恶唑啉酮(azalactones )。中间体3(仅3j被分离)通过打开内酯基内酯和连续形成稠合的2-吡啶酮4进行自发的再循环。尝试合成所选的2 H -chromeno [3,4- f ] -1,7-萘啶6通过Vilsmeier的4e反应失败。相反,发生N-脱乙酰化,然后将氨基甲酰化为甲am7a。另外,通过使3-甲酰基-2-吡啶酮8与衍生自2a的乙二酸内酯和乙酸酐缩合获得吡喃并吡啶9a。