Study of the interaction of 2<i>H</i>-furo[3,2-<i>b</i>]pyran-2-ones with nitrogen-containing nucleophiles

For the first time, the reaction of substituted 2<i>H</i>-furo[3,2-<i>b</i>]pyran-2-ones with diverse <i>N</i>-nucleophiles was investigated. It was shown that the direction of the process depends on the type of employed nitrogen-containing reagent. For example, condensation with aliphatic amines leads to 2<i>H</i>-furo[3,2-<i>b</i>]pyran-2,7(3<i>H</i>)-diones bearing an exocyclic enamine moiety. At the same time, interaction with dinucleophiles results in recyclization accompanied by opening of the furan ring. Relied on the aforementioned process a general method for the synthesis of substituted pyrazol-3-ones with allomaltol fragment was designed. Structures of representatives of all obtained products were unambiguously confirmed by X-ray diffraction.