[{"from": "human", "value": "Design a molecule that meets the criteria outlined in the description. The molecule is a progesterone derivative with antineoplastic activity. Testolactone inhibits steroid aromatase, thereby preventing the formation of estrogen from adrenal androstenedione and reducing endogenous estrogen levels. (NCI04)"}, {"from": "gpt", "value": "[C][C@][C][C][C@H1][C@H1][Branch1][=N][C@@H1][Ring1][=Branch1][C][C][C][=Branch1][C][=O][O][Ring1][O][C][C][C][=C][C][=Branch1][C][=O][C][=C][C@][Ring1][P][Ring1][#Branch1][C]"}]