pipazetate pipazetate pipazetate (inn) (brand names dipect, lenopect, selvigon, theratuss, toraxan), or pipazethate (usan), is a pyridobenzthiazine that was briefly marketed as a cough suppressant, closely related to the phenothiazine class. it binds to the sigma-1 receptor with an ic50 value of 190 nm. it also has local anesthetic action, and in large doses can produce seizures. pipazetateclinical datatrade namesdipect, lenopect, selvignon, selvigon, theratuss, toraxanother namespipazethate; d-254; lg-254; skf-70230a; sq-15874ahfs/drugs.cominternational drug namesatc coder05db11 (who) identifiers iupac name 2-(2-piperidin-1-ylethoxy)ethyl 10h-pyridobenzothiazine-10-carboxylate cas number2167-85-3 6056-11-7 (hydrochloride)pubchem cid22425drugbankdb08796 ychemspider21046 yuniim5ek1t5v2lkeggd05484 ycomptox dashboard (epa)dtxsid40176056 echa infocard100.016.826 chemical and physical dataformulac21h25n3o3smolar mass399.51 g·mol−13d model (jsmol)interactive image smiles o=c(occoccn1ccccc1)n3c4c(sc2c3nccc2)cccc4 inchi inchi=1s/c21h25n3o3s/c25-21(27-16-15-26-14-13-23-11-4-1-5-12-23)24-17-7-2-3-8-18(17)28-19-9-6-10-22-20(19)24/h2-3,6-10h,1,4-5,11-16h2 ykey:dtvjxcomjllmak-uhfffaoysa-n y (verify) as the brand name theratuss, it was approved by the fda in 1962, on evidence of safety only. it was withdrawn from the us market in 1972 when the manufacturer, e.r. squibb, and sons, failed to produce evidence of efficacy. clinical studies showed that it did not decrease cough frequency at recommended dosages. infrequent side effects include nausea, vomiting, drowsiness, fatigue, rash, and tachycardia. synthesis note: 1-azaphenothiazine is also used for making prothipendyl & isothipendyl. thieme synthesis: patent: revised: the reaction of 1-azaphenothiazine (1) with phosgene gives 1-azaphenothiazine-10-carbonyl chloride (2). the reaction of this reactive intermediate with 2-ethanol (3) gives the ester, thus completing the synthesis of pipazethate (4).