Two sulfur-containing analogues of mescaline, 3-thiomescaline and 4-thiomescaline, were synthesized and found to be psychotomimetic in humans, with 4-thiomescaline being 12 times more potent and 3-thiomescaline 6 times more potent than mescaline itself. Three additional analogues of isomescaline were also synthesized but were not psychotomimetic. All five compounds were broken down by bovine plasma monoamine oxidase in the lab, but the rate of this enzymatic degradation did not correlate with their potency as hallucinogens in people.
Two thio analogues of the psychotomimetic drugs DOM and DOET were synthesized and tested in humans. The 5-thio isomers are more potent than the 2-thio isomers but are about ten times less potent than the original sulfur-free drugs. The dithio analogue of DOM showed no central activity at a dose roughly 50 times the effective dose of DOM.
All possible monothio analogues of mono-, di-, and triethoxy homologues of mescaline were synthesized and tested in humans. Modifications at the ring position para to the ethylamine chain, using a sulfur atom, a longer alkyl chain, or both, produce compounds with high central nervous system activity. The 4-n-propoxy and 4-n-butoxy homologues and their corresponding 4-thio analogues were also made and tested. Propyl homologues retain high potency, but a butyl group, with or without sulfur, reduces activity. Meta-ethyl or meta-thio analogues retain some central action, while diethoxy and especially triethoxy homologues are relatively inactive as psychotomimetic drugs.