5-Methoxytryptamine (aka 5-MT, mexamine) is a tryptamine derivative closely related to the neurotransmitters serotonin and melatonin. 5-MT is produced endogenously at low levels; it is biosynthesized by deacetylation of melatonin in the pineal gland. 5-MT acts as a full agonist at the 5-HT1, 5-HT2, 5-HT4, 5-HT6, and 5-HT7 receptors. It is often used as a chemical probe in the study of serotonin receptors, but it has also been used in a clinical trial to mitigate the anemic effects of cisplatin chemotherapy.

Tilomisole (also known as Wy-18,251) is a benzimidazole derivative patented by American Home Products Corp. as an antineoplastic agent with immunomodulating and antimetastatic activity. Tilomisole significantly enhanced the blastogenic response of cancer patients' lymphocytes in vitro. Tilomisole significantly increases macrophage phagocytosis against 51chromium labeled opsonized chicken red blood cells. In preclinical models, Tilomisole administration significantly increases peripheral blood lymphocytes in rats and demonstrates marked anti-inflammatory activity. The acute anti-inflammatory of Tilomisole.) was similar to aspirin, but in contrast to aspirin, Tilomisole failed to demonstrate antipyretic activity. Tilomisole also inhibited chronic inflammatory responses in the adjuvant- and collagen-induced arthritis models. Unfortunately, in clinical trials, Tilomisole failed to demonstrate significant antitumor responses.

Latrunculin A is a naturally occurring toxin that can be purified from the red sea sponge Latrunculia magnifica. It disrupts actin polymerization and prevents mitotic spindle formation; therefore preventing proper cellular replication. It was discovered that latrunculin A has strong anticancer effects, and it was investigated as a treatment candidate for peritoneal dissemination of gastric cancer.

Bisphenol A is a small estrogenic monomer that is polymerized to produce polycarbonate plastic and resins used to line metal cans. It is also used to make some dental sealants. Bisphenol A had been considered to be a very weak environmental estrogen. It is able to interact with human estrogen receptors. In addition, it binds strongly to the estrogen-related receptor gamma. Bisphenol A inhibited androgen-induced androgen receptor transcriptional activity. Prenatal exposure to maternal Bisphenol A concentrations were related to higher levels of anxiety, depression, aggression, and hyperactivity in children. Bisphenol A exposure in childhood was associated with higher levels of anxiety, depression, hyperactivity, inattention, and conduct problems. It never found use as a drug.

Dinaciclib (SCH 727965) is a small molecule inhibitor of cyclin-dependent kinases. Dinaciclib demostrates potent and selective inhibition of CDK2, CDK5, CDK1, and CDK9 activity. Dinaciclib inhibits cell cycle progression and proliferation in various tumor cell lines in vitro. Dinaciclib is a product of a drug discovery collaboration between Pharmacopeia (later Ligand Pharmaceuticals) and Schering-Plough (later Merck & Co.) that began in 1998. Dinaciclib showed promising effect in treating haematological malignancies and solid tumors.

Guanoctine was studied as an antihypertensive agent.

Tideglusib (NP031112, NP-12, Nypta, Noscira SA, Madrid, Spain), a drug, which belongs to the thiadiazolidinone family, is a GSK-3β inhibitor. Tideglusib was in phase II clinical trials for the treatment of Alzheimer disease (AD) and progressive supranuclear palsy. Participants showed no benefit on either of the primary outcome measures or exploratory endpoints and further development in the drug was halted for these two disease. However, Tideglusib is on phase II clinical trial to determine whether drug is safe and efficacious in the treatment of adolescents and adults with congenital and juvenile-onset Myotonic Dystrophy.

Lirequinil is a benzoquinolizinone derivative. It is a partial agonist to the benzodiazepine (BDZ) receptor. Lirequinil slightly lowered the rhythmic slow-wave activity frequency during waking mobility. Lirequinil acts more selectively than nitrazepam to promote the drowsy EEG pattern, and the partial agonistic properties may minimize the residual effects during waking mobility similar to the short-acting agent zopiclone. Lirequinil was well tolerated at all doses, causing no clinically relevant changes in vital signs or laboratory parameters. At doses of 10 and 30 mg there were signs of unsteady gait, indicating a central nervous system depressant effect. Lirequinil had been in phase II for the treatment of sleep disorders.