The reactivity of 6-aminopyrimidin-4(3H)-ones towards DMAD is successfully explained by theoretical investigation (PM3 semiempirical methods). All the PM3 results (activation energies (AE) for the transition states and the heat of formation (ΔH) for the products) support our previous experimental work [J. Cobo et all. Synlett.1993, , 297–299; Tetrahedron1994, , 10345–10354]. In those reactions two main products were obtained: the pyridine derivatives 5 as major ones, which are formed by a tandem DA/RDA reaction with extrusion of the methylisocyanate fragment; and 5-ethenylpyrimidin-4(3H)-ones 10 as minor ones, which arised from a Michael addition, being in competition with the above normal DA.

中文翻译：

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对6-氨基-3-甲基嘧啶-4（3H）-对DMAD的反应性的理论研究。串联Diels-Alder逆Diels-Alder（DA / RDA）反应

通过理论研究（PM3半经验方法）成功地解释了6-氨基嘧啶-4（3H）-对DMAD的反应性。所有的PM3结果（过渡态的活化能（AE）和产品的形成热（ΔH））均支持我们以前的实验工作[J. Cobo等。句法。1993年，，297-299; Tetrahedron 1994，，10345-10354]。在那些反应中，获得了两种主要产物：作为主要衍生物的吡啶衍生物5，其通过串联的DA / RDA反应与甲基异氰酸酯片段的挤出而形成；和5-乙烯基嘧啶-4（3H）-ones 10 作为未成年人，这是由于迈克尔的加入而引起的，与上述正常DA竞争。