compounds (Ib-c) gave the benzopyranyl-(3,2-c)-pyran-2, 10-diones(IIa-b). 3-Acyl-4-hydroxy-coumarins(Id-e) undergo the Kostanecki-Robinson reaction to yield (IIc-d). In Pechmann condensation of 4-hydroxycoumarin with ethyl acetoacetate, 10-methylbenzopyranyl(3,2-c)-pyran-2,8-dione (IVa) is produced. The 10-phenyl derivative (IVb) was obtained via the Kostanecki-Robinson acetylation of 4-hydroxy-3-acetylcoumarin
β-二羰基化合物(Ib-c)的环化得到
苯并
吡喃基-(3,2-c)-pyran-2,10-二
酮(IIa-b)。3-酰基-
4-羟基
香豆素(Id-e)经历Kostanecki-Robinson反应生成(IIc-d)。在
4-羟基
香豆素与
乙酰乙酸乙酯的Pechmann缩合中,产生10-
甲基苯并
吡喃基(3,2-c)-
吡喃-2,8-二
酮(IVa)。通过
4-羟基-3-乙酰
香豆素(Ia)的Kostanecki-Robinson乙酰化获得10-
苯基衍
生物(IVb)。