[{"from": "human", "value": "Use the given information to create a molecule that fulfills the desired purpose. The molecule is a folic acid antagonist and mammalian dihydrofolate reductase inhibitor with antineoplastic activity. Ketotrexate inhibits dihydrofolate reductase, an enzyme that reduces dihydrofolic acid to tetrahydrofolic acid which is essential for the synthesis of purine nucleotides and thymidylate. By depleting tetrahydrofolic acid availability, DNA synthesis is halted."}, {"from": "gpt", "value": "[C][N][C][Branch2][Ring1][Ring1][C][N][C][=C][Ring1][=Branch1][C][=Branch1][C][=O][N][C][=Branch1][Ring2][=N][Ring1][#Branch1][N][C][C][N][C][=C][C][=C][Branch1][Branch1][C][=C][Ring1][=Branch1][C][=Branch1][C][=O][N][C@@H1][Branch1][Branch2][C][C][C][=Branch1][C][=O][O][C][=Branch1][C][=O][O]"}]