Synthesis of new tricyclic ring systems containing the pyrimido[5,4-b][1,4]oxazine skeleton

Article abstract of DOI:10.1002/jhet.5570260341

Synthesis of derivatives 4 and 6 of two novel tricyclic ring systems, 1,2,4-triazolo[3,4-c]pyrimido[5,4-b][1,4]oxazine and imidazo[1,2-c]pyrimido[5,4-b][1,4]oxazine, respectively is described. Although the parent pyrimido[5,4-b]oxazines possess positive i