Microwave Assisted Gould-Jacob Reaction in the Synthesis of Furopyrimidopyrimidines and Their Transformation via Ring Opening to Aminoesters
作者:Nirmal M. Shah、Vivek C. Ramani、Rina D. Shah
DOI:10.14233/ajchem.2017.20873
日期:——
Gould-Jacob reaction is well-known for the construction of fused pyrimidopyrimidines from pyrimidineamines and diethyl ethoxymethylenemalonate (EMME) or acyl malonic ester. Ethyl 4-oxo-8,9-disubstitutedfuro[3,2-e]pyrimidine-3-carboxylates (3) has been carried out by classical heating from furo[2,3-d]pyrimidine-4-amines (1) and diethyl ethoxymethylenemalonate through the formation of uncyclized diethyl N-[5,6-substituted-7H-[2,3-d]pyrimidin-4-yl]aminomethylenemalonates (2) as an intermediate. The identical compound 3 have also been synthesized via rapid solvent free microwave irradiation method. A comparison of classical method versus solvent-free microwave irradiation method has been studied. The reaction of compound 3 has also been explored with alcoholic NaOH and hydrazine hydrate to synthesize corresponding acid 4 and acid hydrazide derivatives 5. Reaction of compound 3 with hydrazine hydrate failed to yield acid hydrazide, but they underwent unexpected ring opening and transformed to respective aminoester 6.
古尔德-雅各布反应(Gould-Jacob reaction)是由嘧啶胺和乙氧基甲叉丙二酸二乙酯(EMME)或丙二酸酰酯生成融合嘧啶并嘧啶的著名反应。4-氧代-8,9-二取代呋喃并[3,2-e]嘧啶-3-羧酸乙酯(3)是以呋喃并[2,3-d]嘧啶-4-胺(1)和乙氧基甲叉丙二酸二乙酯为中间体,通过形成未环化的 N-[5,6-取代-7H-[2,3-d]嘧啶-4-基]氨甲基丙二酸二乙酯(2),经传统加热方法合成的。相同的化合物 3 也是通过快速无溶剂微波辐照法合成的。研究人员对传统方法和无溶剂微波辐照方法进行了比较。还研究了化合物 3 与醇 NaOH 和水合肼的反应,以合成相应的酸 4 和酸酰肼衍生物 5。化合物 3 与水合肼的反应未能生成酸酰肼,但它们发生了意想不到的开环反应,并转化成了相应的氨基酯 6。