Improvements to the Synthesis of Psilocybin and a Facile Method for Preparing the O-Acetyl Prodrug of Psilocin

Abstract: An improved procedure to accomplish the O-phosphor-ylation of 4-hydroxy-N,N-dimethyltryptamine (psilocin 5) is report-ed that utilizes reaction between the O-lithium salt of 5 and tetra-O-benzylpyrophosphate. The O-benzyl groups were removed by cata-lytic hydrogenation over palladium on carbon to afford N,N-dime-thyl-4-phosphoryloxytryptamine (psilocybin, 1). In view of difficulties encountered in the preparation of 1, it is suggested that 4-acetoxy-N,N-dimethyltryptamine (2) may be a useful alternative for pharmacological studies. The latter was obtained following cat-alytic O-debenzylation of 4-benzyloxy-N,N-dimethyltryptamine in the presence of acetic anhydride and sodium acetate. Key words: psilocin, psilocybin, tetra-O-benzylpyrophosphate, phosphorylation Recently, several laboratories have initiated clinical stud-ies of hallucinogenic (psychedelic) agents.1–3 This re-