Structure Elucidation and Spectroscopic Analysis of Chromophores Produced by Oxidative Psilocin Dimerization

Psilocin, the psychoactive compound derived from psilocybin, turns blue when mushrooms containing it are bruised. This blue color was previously thought to come from a specific chemical dimer (5,5'-coupled quinone). By synthesizing stable, ring-methylated derivatives of psilocin and analyzing their oxidized forms with spectroscopy and computational modeling, researchers showed that the blue color actually arises from a different dimer (7,7'-coupled quinoid). The original hypothesis was not supported.

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Abstract

Abstract Psilocin ( 1 ) is the dephosphorylated and psychotropic metabolite of the mushroom natural product psilocybin. Oxidation of the phenolic hydroxy group at the C‐4 position of 1 results in formation of oligomeric indoloquinoid chromophores responsible for the iconic blueing of bruised psilocybin‐producing mushrooms. Based on previous NMR experiments, the hypothesis included that the 5,5’‐coupled quinone dimer of 1 was the primary product responsible for the blue color. To test this hypothesis, ring‐methylated 1 derivatives were synthesized to provide stable analogs of 1 dimers that could be completely characterized. The chemically oxidized derivatives were spectroscopically analyzed and compared to computationally derived absorbance spectra. Experimental evidence did not support the original hypothesis. Rather, the blue color was shown to stem from the quinoid 7,7’‐coupled dimer of 1 .