Design, Synthesis, and X-ray Crystal Structure of Classical and Nonclassical 2-Amino-4-oxo-5-substituted-6-ethylthieno[2,3- d ]pyrimidines as Dual Thymidylate Synthase and Dihydrofolate Reductase Inhibitors and as Potential Antitumor Agents

Design, Synthesis, and X-ray Crystal Structure of Classical and Nonclassical 2-Amino-4-oxo-5-substituted-6-ethylthieno[2,3- d ]pyrimidines as Dual Thymidylate Synthase and Dihydrofolate Reductase Inhibitors and as Potential Antitumor Agents