phenylbiguanide phenylbiguanide phenylbiguanide (pbg) is a 5-ht3 agonist used to study the role of 5-ht3 receptors in the central nervous system. it has been found to trigger dopamine release in the nucleus accumbens of rats. phenylbiguanidelegal statuslegal status un: unscheduled identifiers iupac name 1-phenylbiguanide cas number102-02-3pubchem cid4780chemspider4616uniiw8pka3t2i3chebichebi:75377chemblchembl13791comptox dashboard (epa)dtxsid90144508 echa infocard100.002.726 chemical and physical dataformulac8h11n5molar mass177.211 g·mol−13d model (jsmol)interactive imagemelting point135–142 °c (275–288 °f) smiles c1ccc(cc1)nc(=n)nc(=n)n inchi inchi=1s/c8h11n5/c9-7(10)13-8(11)12-6-4-2-1-3-5-6/h1-5h,(h6,9,10,11,12,13)key:cuqcmxfwimowrp-uhfffaoysa-n derivatives phenylbiguanide is used to make amanozine and benfosformin.