[{"from": "human", "value": "Generate a molecule based on this description. The molecule is an unsaturated pentahydrocarbon, Isoprene is found in certain plants or obtained by distillation of caoutchouc or gutta-percha. In plants, it is elementary in the formation of isoprenoids, fat-soluble vitamins, carotenoids and related pigments. Isoprenes contribute to flavors and fragrances of essential oils and other plant-derived substances. (NCI04)"}, {"from": "gpt", "value": "[C][C][=Branch1][C][=C][C][=C]"}]