[{"from": "human", "value": "Create a molecule that satisfies the conditions outlined in the description. The molecule is a butan-4-olide that is dihydrofuran-2-one substituted at C-3 and C-4 by hydroxy groups (the 3S,4R-diastereomer). It is a diol and a butan-4-olide. It is an enantiomer of a L-threonolactone."}, {"from": "gpt", "value": "[C][C@H1][Branch1][N][C@@H1][Branch1][Branch2][C][=Branch1][C][=O][O][Ring1][=Branch1][O][O]"}]