Synthesis of 4-(2-(piperazin-1-yl)-7,8-dihydro-5H-thiopyrano[4,3-d] pyrimidin-4-yl)morpholine and 4-morpholino-2-(piperazin-1-yl)-7,8-dihydro-5H-thiopyrano[4,3-d]pyrimidine 6,6-dioxide

Two novel thiopyrano[4,3-d]pyrimidine derivatives 7 and 8 were synthesized from dimethyl 3,3'-thiodipropanoate through six steps including two times of cyclization, chlorination, oxidation, substitution with morpholine and piperazine and their structures were confirmed by H-1 NMR and MS spectrum. The total yield of the six steps was 18.6% (calculated from methyl dimethyl 3,3'-thiodipropanoate). The synthetic routes of them can be used to synthesize PI3K/mTOR inhibitors bearing a thiopyrano[4,3-d] pyrimidine nucleus.