In this study analogues of compounds based on pyrano[2,3-d]pyrimidine were synthesized. 1,3-dimethyl-5-
(thiomethyl)-2,4,7-trioxo-1,3,4,7-tetrahydro-2H-pyrano[2,3-d]pyrimidine-6-carboxylic acid 3 and 1,3-dimethyl-5-
(thiomethyl)-2H-pyrano[2,3-d]pyrimidine-2,4,7(1H,3H)-trione 4 were obtained by the treatment of Triethylammonium 5-
[(2,2-dimethyl-4,6-dioxo-1,3-dioxan-5-ylidene)(thiomethyl)methyl]-1,3-dimethylpyrimidine-2,4,6-trionate 1 with methyl
sulfonic acid and pyridine, respectively. 5,5-dianilino-1,3-dimethyl-5,6-dihydro-2H-pyrano[2,3-d]pyrimidine-
2,4,7(1H,3H)-trione 6 was obtained after oxidizing compound 4 to produce 1,3-dimethyl-5-(methylsulfinyl)-2Hpyrano[
2,3-d]pyrimidine-2,4,7(1H,3H)-trione 5 , then the sulfoxide group on compound 5 was replaced by aniline group.