Spirotriazine is a dihydrotriazine derivative patented by Burroughs Wellcome & Co. (U.S.A.) Inc. as the anthelmintic agent. In preclinical models, Spirotriazine shows potent activity against intestinal parasites and negligible microbiological activity.

Fosquidone (also known as GR63178A), a pentacyclic pyrroloquinone that was developed as an anticancer agent. Fosquidone participated in phase II clinical trial for the treatment of patients with colorectal, renal and non-small cell lung cancer. However, the drug didn’t show significant antitumor activity. The further development of this drug was discontinued.

LAGOCICLOVIR is a nucleoside reverse transcriptase inhibitor with activity against human immunodeficiency virus and hepatitis B virus.

Tofetridine is an analgesic agent.

Revamilast is an orally active, potent and selective phosphodiesterase 4 (PDE 4) inhibitor that is being studied for its potential in treatment of inflammatory disorders. PDE 4 inhibitors attenuate the inflammatory response and suppress many cytokines, including TNF-α production in mononuclear cells. Initial studies showed no serious adverse events in healthy volunteers and phase II studies have evaluated the effect of revamilast on long function and rheumatoid arthritis.

Seliciclib (CYC202, R-roscovitine) is a second-generation orally available cyclin-dependent kinases (CDKs) inhibitor that competes for ATP binding sites on these kinases. It is a direct inhibitor of cyclin CDK2/E, CDK2/A and it has inhibitory effects on cyclin H/CDK7, CDK5, and CDK9. CDKs are enzymes that are central to the process of cell division and cell cycle control and play pivotal roles in cancer cell growth and DNA damage repair. Seliciclib exerts an anti-proliferative effect via several key mechanisms: selective downregulation of proliferative and survival proteins and upregulation of p53, leading to growth arrest or apoptosis. The second one is decreasing phosphorylation of Rb and modulating E2F transcriptional activity leading to growth arrest or apoptosis. Seliciclib is currently in phase II clinical trial as a drug candidate for the treatment of Cushing's disease and as a potential therapeutic agent for the treatment of cystic fibrosis (CF). In addition, it is in Phase II trials for non-small cell lung cancer and nasopharyngeal carcinoma.

Metrifudil (previously known as Y-341) is a synthetic adenosine analog that is acid stable and has a prolonged duration of action. Metrifudil is a selective adenosine A2 receptor agonist and has anticonvulsant activity against seizures. The drug is also studied for the treatment of glomerulonephritis. However, no recent development has been reported.

Danitracen (WA 335) is an antidepressant compound developed in the 1970s. Danitracen acts by blocking central and peripheral 5-HT receptors: it potentiates testosterone-induced sexual behavior in rats and abolishes the 5-hydroxytryptophan (5-HTP) induced hypermotility in mice. In amphetamine-treated rats, administration of danitracen lowered whole brain serotonin and norepinephrine levels. Danitracen investigated in clinical trials in depressed patients. At 3 mg/day, danitracen was equipotent to 150 mg/day amitriptyline.

Bucricaine is tetrahydroaminoacridine derivative that has been studied as acetylcholinesterase and monoamine oxidase inhibitor. In animal models, Bucricaine shows a wide spectrum of pharmacological properties, which include analgesic, local anesthetic, analeptic, and respiratory stimulant activities.