[{"from": "human", "value": "Create a molecule with the structure as the one described. The molecule is a vaccenate(1-) having a trans- double bond. It has a role as a human metabolite. It is a vaccenate(1-) and an octadecenoate. It is a conjugate base of a trans-vaccenic acid."}, {"from": "gpt", "value": "[C][C][C][C][C][C][/C][=C][/C][C][C][C][C][C][C][C][C][C][=Branch1][C][=O][O-1]"}]