[{"from": "human", "value": "Provide a brief overview of this molecule. [C][C@@H1][Branch1][#Branch1][C][=Branch1][C][=O][O][C][N][P][=Branch1][C][=O][Branch2][Ring1][P][O][C][C@@H1][C@H1][Branch2][Ring1][=Branch2][C][C@@H1][Branch1][Ring2][O][Ring1][Branch1][N][C][=C][Branch1][#Branch2][C][=Branch1][C][=O][N][C][Ring1][#Branch1][=O][/C][=C][/Br][O][O][C][=C][C][=C][C][=C][Ring1][=Branch1]"}, {"from": "gpt", "value": "The molecule is a novel small molecule anticancer agent. Thymectacin is selectively active against tumor cells expressing high levels of thymidylate synthase (TS), a critical enzyme in DNA biosynthesis. Thymectacin was as efficacious as irinotecan, a drug recently approved for the treatment of 5-fluorouracil-resistant colon cancer."}]