o-1918 o-1918 o-1918 is a synthetic compound related to cannabidiol, which is an antagonist at two former orphan receptors gpr18 and gpr55, that appear to be related to the cannabinoid receptors. o-1918 is used in the study of these receptors, which have been found to be targets for a number of endogenous and synthetic cannabinoid compounds, and are thought to be responsible for most of the non-cb1, non-cb2 mediated effects that have become evident in the course of cannabinoid research. o-1918identifiers iupac name 1,3-dimethoxy-5-methyl-2-benzene cas number536697-79-7 ypubchem cid40469923unii2dgr9z5bt3comptox dashboard (epa)dtxsid10610371 chemical and physical dataformulac19h26o2molar mass286.19 g·mol−13d model (jsmol)interactive image smiles cc1=c(c2=c(oc)c=c(c)c=c2oc)(c(c)=c)cc1