Fluorenol
Fluorenol is an alcohol derivative of fluorene. In the most significant isomer, fluoren-9-ol or 9-hydroxyfluorene, the hydroxy group is located on the bridging carbon between the two benzene rings. Hydroxyfluorene can be converted to fluorenone by oxidation. It is a white-cream colored solid at room temperature. Toxicity. Fluorenol is toxic to aquatic organisms including algae, bacteria, and crustaceans. Fluorenol was patented as an insecticide in 1939, and is an algaecide against the green algae "Dunaliella bioculata". Its toxicity and carcinogenicity in humans are unknown. Eugeroic. A study published by Cephalon describing research to develop a successor  to the eugeroic modafinil reported that the corresponding fluorenol derivative was 39% more effective than modafinil at keeping mice awake over a 4-hour period. However, after further investigation it was determined that the eugeroic activity of the fluorenol analog was likely due to an active metabolite, which they identify as fluorenol itself. Fluorenol is a weak dopamine reuptake inhibitor with an IC of 9 μM, notably 59% weaker than modafinil (IC = 3.70 μM), potentially making it even less liable for addiction. It also showed no affinity for cytochrome P450 2C19, unlike modafinil.