Psilacetin derivatives: fumarate salts of the meth­yl–ethyl, meth­yl–allyl and diallyl variants of the psilocin prodrug

The solid-state structures of the salts of three psilacetin derivatives, namely, 4-acet­oxy-N-eth­yl-N-methyl­tryptammonium (4-AcO-MET) hydro­fumarate {sys­tematic name: [2-(4-acet­yloxy-1H-indol-3-yl)eth­yl](meth­yl)ethyl­aza­nium 3-carb­oxy­prop-2-enoate}, C(15)H(21)N(2)O(2) (+)·C(4)H(3)O(4) (−), 4-acet­oxy-N-allyl-N-methyl­tryptammonium (4-AcO-MALT) hydro­fumarate {systematic name: [2-(4-acet­yl­oxy-1H-indol-3-yl)eth­yl](meth­yl)prop-2-enyl­aza­nium 3-carb­oxy­prop-2-eno­ate}, C(16)H(21)N(2)O(2) (+)·C(4)H(3)O(4) (−), and 4-acet­oxy-N,N-di­allyl­tryptammonium (4-AcO-DALT) fumarate–fumaric acid (1/1) (systematic name: bis­{[2-(4-acet­yloxy-1H-indol-3-yl)eth­yl]diprop-2-enyl­aza­nium} but-2-enedioate–(E)-butenedioic acid (1/1)), 2C(18)H(23)N(2)O(2) (+)·C(4)H(2)O(4) (2−)·C(4)H(4)O(4), are reported. All three salts possess a protonated tryptammonium cation. The 4-AcO-MET and 4-AcO-MALT compounds are charge-balanced by 3-carb­oxy­acrylate (hydro­fumarate) anions. The 4-AcO-DALT complex crystallizes as a two-to-one tryptammonium-to-fumarate salt, which co-crystallizes with a fumaric acid mol­ecule. Each structure is consolidated by N—H⋯O and O—H⋯O hydrogen bonds.