Synthesis
An efficient synthesis of 2, 3-dihydro-1H-pyrimido [1, 2-a] quinoxaline 6-oxides
MB Garcia, LR Orelli, ML Magri, IA Perillo
Index: Garcia, Maria B.; Orelli, Liliana R.; Magri, Maria L.; Perillo, Isabel A. Synthesis, 2002 , # 18 p. 2687 - 2690
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Citation Number: 9
Abstract
Abstract 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, ...