ethyl ethoxymethylideneacetoacetate proceeded regioselectively, giving 2-R-7-methyl[1,2,4]triazolo[2,3-a]-pyrimidines in good yields. The compounds obtained were characterized by elemental analysis, 1H NMR spectroscopy, and X-ray diffraction analysis (for ethyl 2-ethylthio-7-methyl[1,2,4]triazolo[2,3-a]pyrimidine-6-carboxylate). The frontier orbitals, the molecular electrostatic potential, and the geometries
                                    5-R-3-
氨基-
1,2,4-三唑与乙氧基亚甲基
乙酰丙酮和
乙氧基亚甲基乙酰乙酸乙酯的反应区域选择性地进行,得到2-R-7-甲基[1,2,4]三唑并[2,3-a]-
嘧啶收益良好。所得化合物通过元素分析、1H NMR光谱和X射线衍射分析(对于2-乙
硫基-7-甲基[1,2,4]三唑并[2,3-a]
嘧啶-6-
羧酸乙酯) . 通过 DFT 方法 (B3LYP/6-31G**) 计算了前沿轨道、分子静电势和试剂分子的几何形状。