jwh-203 jwh-203 jwh-203 (1-pentyl-3-(2-chlorophenylacetyl)indole) is an analgesic chemical from the phenylacetylindole family that acts as a cannabinoid agonist with approximately equal affinity at both the cb1 and cb2 receptors, having a ki of 8.0 nm at cb1 and 7.0 nm at cb2. it was originally discovered by, and named after, john w. huffman, but has subsequently been sold without his permission as an ingredient of synthetic cannabis smoking blends. similar to the related 2'-methoxy compound jwh-250, the 2'-bromo compound jwh-249, and the 2'-methyl compound jwh-251, jwh-203 has a phenylacetyl group in place of the naphthoyl ring used in most aminoalkylindole cannabinoid compounds, and has the strongest in vitro binding affinity for the cannabinoid receptors of any compound in the phenylacetyl group. jwh-203legal statuslegal status ca: schedule ii de: anlage ii (authorized trade only, not prescriptible) uk: class b us: schedule i i-n (poland) identifiers iupac name 2-(2-chlorophenyl)-1-(1-pentylindol-3-yl)ethanone cas number864445-54-5 y (jwh-203)864445-55-6 (jwh-204)pubchem cid44397500chemspider23256082unii52cp80v8fycomptox dashboard (epa)dtxsid00235557 echa infocard100.233.381 chemical and physical dataformulac21h22clnomolar mass339.86 g·mol−13d model (jsmol)interactive image smiles clc2ccccc2cc(=o)c1cn(ccccc)c3ccccc13 inchi inchi=1s/c21h22clno/c1-2-3-8-13-23-15-18(17-10-5-7-12-20(17)23)21(24)14-16-9-4-6-11-19(16)22/h4-7,9-12,15h,2-3,8,13-14h2,1h3key:ydinkdbazjoslv-uhfffaoysa-n (verify) unexpectedly despite its weaker cb1 ki in vitro, the 2-methylindole derivative jwh-204 is actually more potent than jwh-203 in animal tests for cannabinoid activity, though it is still weaker than jwh-249. jwh-204 legal status in the united states, jwh-203 is a schedule i controlled substance. as of october 2015, jwh-203 is a controlled substance in china.