A One-Pot Synthesis of Azolo-annulated Derivatives of Pyrido[2,3-d]pyrimidine 6-Nitro[1,2,4]triazolo- and 6-nitropyrazolo[1,5-a]pyrimidines 1a-h react with malononitrile and ethyl cyanoacetate to yield 9-imino-, 2a-h, and 9-oxo-7-nitro-4,9-dihydroazolo[1,5-a]pyrido-[2,3-d]pyrimidines 4a-g, respectively. By using the N*C*-double-labelled ethyl cyanoacetate in this reaction, its participation as a 1,3-bifunctional reagent was established. Malononitrile or ethyl cyanoacetate provide the C-C-N fragment for the pyridine ring. The mechanism is discussed.
5-a]
嘧啶 1a-h 与
丙二腈和
氰乙酸乙酯反应,分别生成 9-亚
氨基、2a-h 和 9-氧代-7-硝基-4,9-二氢唑并[1,5-a]
吡啶并[2,3-d]
嘧啶 4a-g。通过在该反应中使用 N*C* 双标记的
氰乙酸乙酯,确定了
氰乙酸乙酯作为 1,3 双功能试剂的参与性。
丙二腈或
氰基
乙酸乙酯为
吡啶环提供了 C-C-N 片段。对其机理进行了讨论。