[{"from": "human", "value": "Synthesize a molecule that matches the given characteristics. The molecule is produced in the corpus luteum and by the placenta, as an antagonist of estrogens. Promotes proliferation of uterine mucosa and the implantation of the blastocyst, prevents further follicular development."}, {"from": "gpt", "value": "[C][C][=Branch1][C][=O][C@H1][C][C][C@@H1][C@@][Ring1][Branch1][Branch2][Ring1][#Branch1][C][C][C@H1][C@H1][Ring1][=Branch1][C][C][C][=C][C][=Branch1][C][=O][C][C][C@][Ring1][O][Ring1][#Branch1][C][C]"}]