The acylketene S,N-acetals 1 react with one equivalent of malonyl chloride in the presence of triethylamine to give novel 1,5-substituted 4-hydroxy-6-methylthio-2(1H)-pyridones 3 in good yields. However, in the presence of excess of malonyl chloride (three equivalents), the reaction proceeds further to give the corresponding pyrano[3,2-c] pyridones derivatives 4 in moderate yields.
酰基烯酮S,N-
缩醛1与一当量
丙二酰氯在
三乙胺存在下反应,以良好的收率得到新型1,5-取代的
4-羟基-6-甲
硫基-2(1H)-
吡啶酮3。然而,在过量
丙二酰氯(三当量)存在下,反应进一步进行,以中等收率得到相应的
吡喃并[3,2-c]
吡啶酮衍
生物4。