Sulfur analogues of psychotomimetic agents.  3.  Ethyl homologues of mescaline and their monothio analogues. 
All possible monothio analogues of the mono-, di-, and triethoxy homologues of mescaline have been synthesized and pharmacologically evaluated in man.  Modifications at the ring position para to the ethylamine chain, either with a sulfur atom, a longer alkyl chain, or both, lead to compounds of high central nervous system activity.  The 4-n-propoxy and 4-n-butoxy homologues and their corresponding 4-thio analogues were also synthesized and pharmacologically evaluated.  The propyl homologues retain high potency, but a butyl group (either with or without a sulfur atom) leads to a decrease in activity.  The m-ethyl or m-thio analogues retain some central action but the diethoxy and especially the triethoxy homologues are relatively inactive as psychotomimetic drugs.