α-Pyrones. Part V. Structure effects on the intramolecular cyclization of functionalized 6-pyronylacetamides: Synthesis of new 2,5,7-trioxo-pyrano [3,2-c]pyridines
作者:Francesca Clerici、Maria L Gelmi、Barbara Galbiati、Sabrina Mottadelli、Michele Penso、Donato Pocar
DOI:10.1016/0040-4020(95)00050-i
日期:1995.3
conditions using anhydrous potassium carbonate as a base to give the Cα-alkyl derivatives 7 in good yields. Intramolecular cyclization with different bases and solvents of acetamides 3,5–7 to give the new 2,5,7-trioxo-pyrano[3,2-c]pyridines has been studied.
芳基异氰酸酯2与2-氧代-2 H-吡喃-6-乙酸甲酯1和内酯4的反应分别得到两类吡喃基乙酰胺3和5。膦5被还原成相应的乙酰胺6与锌和乙酸。化合物6用无水碳酸钾作为碱,得到为固体-液体PTC条件下烷基化α -烷基衍生物7以良好的收率。分子内环化用不同的碱和3,5-7的乙酰胺溶剂得到新的2,5,7-三氧代-吡喃并[3,2- c已经研究了]吡啶。