[{"from": "human", "value": "Generate a molecule based on this description. The molecule is an unbranched nineteen-carbon alkene with one double bond between C-1 and C-2. It has a role as a plant metabolite and a bacterial metabolite."}, {"from": "gpt", "value": "[C][C][C][C][C][C][C][C][C][C][C][C][C][C][C][C][C][C][=C]"}]