[{"from": "human", "value": "Use the given information to create a molecule that fulfills the desired purpose. The molecule is an S-ethylhomocysteine that has R-configuration at the chiral centre. It is an enantiomer of a L-ethionine."}, {"from": "gpt", "value": "[C][C][S][C][C][C@H1][Branch1][=Branch1][C][=Branch1][C][=O][O][N]"}]