Abstract
Four new pyrimido-1, 4-diazepine derivatives, 2, 4, 6, 8-tetramethyl-3H-pyrimido[4, 5-b]-[1, 4]diazepine-7, 9(6H, 8H)-dione (IV), 2, 4-diphenyl-6, 8-dimethyl-3H-pyrimido[4, 5-b][1, 4]-diazepine-7, 9(6H, 8H)-dione(VII), 4-phenyl-2, 6, 8-trimethyl-3H- pyrimido[4, 5-b][1, 4]-diazepine-7, 9(6H, 8H)-dione(X), and 2-phenyl-4, 6, 8-trimethyl-3H-pyrimido[4, 5-b][1, 4]-diazepine-7, 9(6H, 8H)-dione(XI), were synthesized. When 5, 6-diamino-1, 3-dimethyluracil(I) was heated in butanol with acetylacetone, dibenzoylmethane, or benzoylacetone, 4-(6-amino-1, 3-dimethyl-2, 4-dioxo-1, 2, 3, 4-tetrahydro-5-pyrimidylamino)-3-penten-2-one (III), 1, 3-diphenyl-3-(6-amino-1, 3-dimethyl-2, 4-dioxo-1, 2, 3, 4-tetrahydro-5-pyrimidylamino)-2-propen-1-one(V), or 1-phenyl-3-(6-amino-1, 3-dimethyl-2, 4-dioxo-1, 2, 3, 4-tetrahydro-5-pyrimidylamino)-2-buten-1-one (IX) were obtained, respectively, under elimination of water. Heating of I with acetylacetone, dibenzoylmethane or benzoylacetone in polyphosphoric acid afforded IV, VII, or X, were and in the case of heating I with benzoylacetone, XI was obtained in a poor yield besides X. IV, VII, and X were also obtained by heating III, V, and IX in polyphosphoric acid.
