etazolate

{{Short description|Chemical compound}}

{{Drugbox

| IUPAC_name = Ethyl 1-ethyl-4-[2-(propan-2-ylidene)hydrazinyl]-1H-pyrazolo[3,4-b]pyridine-5-carboxylate

| image = Etazolate.svg

| tradename =

| pregnancy_category =

| legal_status = Uncontrolled

| routes_of_administration = Oral

| bioavailability =

| metabolism =

| elimination_half-life =

| excretion =

| IUPHAR_ligand = 7336

| CAS_number = 51022-77-6

| ATC_prefix = none

| ATC_suffix =

| PubChem = 3277

| ChemSpiderID = 3162

| ChEBI = 138502

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = I89Y79062L

| ChEMBL = 356388

| C=14 | H=19 | N=5 | O=2

| smiles = CCN1C2=NC=C(C(=C2C=N1)NN=C(C)C)C(=O)OCC

| StdInChI = 1S/C14H19N5O2/c1-5-19-13-10(8-16-19)12(18-17-9(3)4)11(7-15-13)14(20)21-6-2/h7-8H,5-6H2,1-4H3,(H,15,18)

| StdInChIKey = OPQRBXUBWHDHPQ-UHFFFAOYSA-N

}}

Etazolate (SQ-20,009, EHT-0202) is an anxiolytic drug which is a pyrazolopyridine derivative and has unique pharmacological properties.{{cite book | vauthors = Hall JA, Morton I | title = Concise dictionary of pharmacological agents: properties and synonyms | publisher = Kluwer Academic | year = 1999 | isbn = 0-7514-0499-3 | url = https://books.google.com/books?id=mqaOMOtk61IC&q=etazolate&pg=PA115}}{{cite journal | vauthors = Williams M | title = Anxioselective anxiolytics | journal = Journal of Medicinal Chemistry | volume = 26 | issue = 5 | pages = 619–628 | date = May 1983 | pmid = 6132997 | doi = 10.1021/jm00359a001 }}{{cite journal | vauthors = Williams M, Risley EA | title = Enhancement of the binding of 3H-diazepam to rat brain membranes in vitro by SQ 20009, A novel anxiolytic, gamma-aminobutyric acid (GABA) and muscimol | journal = Life Sciences | volume = 24 | issue = 9 | pages = 833–841 | date = February 1979 | pmid = 449623 | doi = 10.1016/0024-3205(79)90367-9 }} It acts as a positive allosteric modulator of the GABA_A receptor at the barbiturate binding site,{{cite journal | vauthors = Zezula J, Slany A, Sieghart W | title = Interaction of allosteric ligands with GABAA receptors containing one, two, or three different subunits | journal = European Journal of Pharmacology | volume = 301 | issue = 1–3 | pages = 207–214 | date = April 1996 | pmid = 8773466 | doi = 10.1016/0014-2999(96)00066-0 }}{{cite book | vauthors = Davies MF | chapter = The Pharmacology of the Gamma-Aminobutyric Acid System| veditors = Remington G, Baskys A | title = Brain mechanisms and psychotropic drugs | publisher = CRC Press | location = Boca Raton | year = 1996 | isbn = 0-8493-8386-2 | chapter-url = https://books.google.com/books?id=SPEIn0S6aK8C&q=etazolate&pg=PA109}}{{cite book | vauthors = Olsen RW, Gordey M | chapter = GABAA Receptor Chloride Ion Channels | veditors = Mishina M, Kurachi Y | title = Pharmacology of ionic channel function: activators and inhibitors | series = Handbook of Experimental Pharmacology | publisher = Springer | location = Berlin | year = 2000 | volume = 147 | pages = 499–517 | isbn = 3-540-66127-1 | chapter-url = https://books.google.com/books?id=t7i4yNiXiFMC&q=etazolate&pg=PA503 | doi = 10.1007/978-3-642-57083-4_19 }}{{cite book | vauthors = Olsen RW | chapter= GABA-Drug Interactions | veditors = Jucker E | title = Progress in Drug Research | volume = 31 | publisher = Birkhauser | location = Boston | year = 1987 | page = 526 | isbn = 3-7643-1837-6 | chapter-url = https://books.google.com/books?id=gx6dwxmlQwMC&q=etazolate&pg=PA225}} as an adenosine antagonist of the A₁ and A₂ subtypes,{{cite journal | vauthors = Williams M, Jarvis MF | title = Adenosine antagonists as potential therapeutic agents | journal = Pharmacology, Biochemistry, and Behavior | volume = 29 | issue = 2 | pages = 433–441 | date = February 1988 | pmid = 3283781 | doi = 10.1016/0091-3057(88)90182-7 | s2cid = 35635747 }} and as a phosphodiesterase inhibitor selective for the PDE4 isoform.{{cite journal | vauthors = Chasin M, Harris DN, Phillips MB, Hess SM | title = 1-Ethyl-4-(isopropylidenehydrazino)-1H-pyrazolo-(3,4-b)-pyridine-5-carboxylic acid, ethyl ester, hydrochloride (SQ 20009)--a potent new inhibitor of cyclic 3',5'-nucleotide phosphodiesterases | journal = Biochemical Pharmacology | volume = 21 | issue = 18 | pages = 2443–2450 | date = September 1972 | pmid = 4345859 | doi = 10.1016/0006-2952(72)90414-5 }}{{cite journal | vauthors = Wang P, Myers JG, Wu P, Cheewatrakoolpong B, Egan RW, Billah MM | title = Expression, purification, and characterization of human cAMP-specific phosphodiesterase (PDE4) subtypes A, B, C, and D | journal = Biochemical and Biophysical Research Communications | volume = 234 | issue = 2 | pages = 320–324 | date = May 1997 | pmid = 9177268 | doi = 10.1006/bbrc.1997.6636 }}{{cite book | vauthors = Daniel JL | chapter = Platelet signalling; cAMP and cGMP | veditors = Gresele P | title = Platelets in thrombotic and non-thrombotic disorders: pathophysiology, pharmacology and therapeutics | publisher = Cambridge University Press | location = Cambridge, UK | year = 2002 | isbn = 0-521-80261-X | chapter-url = https://books.google.com/books?id=W1O-rgRYSdEC&q=etazolate+%22PDE4%22&pg=PA294}} It is currently in clinical trials for the treatment of Alzheimer's disease.{{cite web | url = http://www.exonhit.com/therapeutics/pipeline#eht_0202 | title = EHT 0202 | work = Pipeline | publisher = ExonHit | access-date = | archive-url = https://web.archive.org/web/20110111115443/http://www.exonhit.com/therapeutics/pipeline#eht_0202 | archive-date = 2011-01-11 | url-status = dead }}