Synthesis and anticancer evaluation of diaryl pyrido[2,3-d]pyrimidine /alkyl substituted pyrido[2,3-d]pyrimidine derivatives as thymidylate synthase inhibitors

二芳基吡啶并[2,3-d]嘧啶/烷基取代的吡啶并[2,3-d]嘧啶衍生物作为胸苷酸合酶抑制剂的合成及抗癌评价