An Efficient Synthesis of 2,3-Dihydro-1<i>H-</i>pyrimido[1,2-<i>a</i>]quinoxaline 6-Oxides
作者:Isabel A. Perillo、María B. García、Liliana R. Orelli、María L. Magri
DOI:10.1055/s-2002-35980
日期:——
5-Substituted 2,3-dihydro-1H-pyrimido[1,2-a]quinoxaline 6-oxides 1a-f were synthesized by ring closure of N-acyl-N′-(o-nitroaryl)-1,3-propanediamines 2 with ethyl polyphosphate (PPE) or trimethylsilyl polyphosphate (PPSE) to the corresponding 2-substituted 1-(o-nitroaryl)-1,4,5,6-tetrahydropyrimidines 3, followed by spontaneous heterocyclization. The method was extended to the synthesis of the homologous 6-aryl-1,2,3,4-tetrahydro-1,3-diazepino[1,2-a]quinoxaline 7-oxide (1g).
5 取代的 2,3-二氢-1H-嘧啶并[1,2-a]喹喔啉 6-氧化物 1a-f 是通过 N-酰基-N′-(邻硝基芳基)-1、通过 N-酰基-N′-(邻硝基芳基)-1,4,5,6-四氢嘧啶 2 与多磷酸乙酯 (PPE) 或多磷酸三甲基硅酯 (PPSE) 的环闭合,合成相应的 2-取代 1-(邻硝基芳基)-1,4,5,6-四氢嘧啶 3,然后自发杂环化。 该方法还可用于合成同源的 6-芳基-1,2,3,4-四氢-1,3-二氮杂卓[1,2-a]喹喔啉 7-氧化物(1g)。