514225-45-7Relevant articles and documents
An efficient synthesis of 2,3-dihydro-1H-pyrimido[1,2-a]quinoxaline 6-oxides
Garcia, Maria B.,Orelli, Liliana R.,Magri, Maria L.,Perillo, Isabel A.
, p. 2687 - 2690 (2002)
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).