Cartazolate (SQ-65,396) is a drug of the pyrazolopyridine class. It acts as a GABA_A receptor

positive allosteric modulator In pharmacology and biochemistry, allosteric modulators are a group of substances that bind to a receptor to change that receptor's response to stimulus. Some of them, like benzodiazepines, are drugs. The site that an allosteric modulator binds to ...

at the barbiturate

binding site In biochemistry and molecular biology, a binding site is a region on a macromolecule such as a protein that binds to another molecule with specificity. The binding partner of the macromolecule is often referred to as a ligand. Ligands may includ ...

of the complex and has

anxiolytic An anxiolytic (; also antipanic or antianxiety agent) is a medication or other intervention that reduces anxiety. This effect is in contrast to anxiogenic agents which increase anxiety. Anxiolytic medications are used for the treatment of anxiet ...

effects in animals. It is also known to act as an adenosine antagonist at the A₁ and A₂ subtypes and as a

phosphodiesterase inhibitor A phosphodiesterase inhibitor is a drug that blocks one or more of the five subtypes of the enzyme phosphodiesterase (PDE), thereby preventing the inactivation of the intracellular second messengers, cyclic adenosine monophosphate (cAMP) and cyc ...

. Cartazolate was tested in human

clinical trial Clinical trials are prospective biomedical or behavioral research studies on human participants designed to answer specific questions about biomedical or behavioral interventions, including new treatments (such as novel vaccines, drugs, diet ...

s and was found to be efficacious for

anxiety Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat wh ...

but was never marketed. It was developed by a team at E.R. Squibb and Sons in the 1970s.

Synthesis

Condensation of aminopyrazole (1) with diethyl ethoxymethylenemalonate (2) gives the product of the addition-elimination (3). The product tautomerizes spontaneously to the hydroxypyridine (4). The hydroxyl group is then converted to the chloro-derivative by means of

phosphorus oxychloride Phosphoryl chloride (commonly called phosphorus oxychloride) is a colourless liquid with the formula . It hydrolyses in moist air releasing phosphoric acid and fumes of hydrogen chloride. It is manufactured industrially on a large scale from pho ...

(5). Displacement of halogen by ''n''-butylamine gives the antidepressant compound cartazolate. Displacement of halogen by the basic nitrogen of acetone hydrazone affords the antidepressant etazolate.

References

{{Phosphodiesterase inhibitors Adenosine receptor antagonists Amines Ethyl esters Carboxylate esters GABAA receptor positive allosteric modulators Phosphodiesterase inhibitors Pyrazolopyridines Butyl compounds

Synthesis

See also

References