Speeter–Anthony route
The Speeter–Anthony route, also known as the Speeter–Anthony tryptamine synthesis (STS), is a well-known and widely used chemical synthesis route used in the synthesis of tryptamines, including psychedelic tryptamines like psilocin and 5-MeO-DiPT.[1][2][3] It starts with indole or a ring-substituted indole.[1][2] The scheme of the route is as follows:[2]
The route was first described by Merrill E. Speeter and William C. Anthony in 1954.[4]
Other tryptamine synthesis routes have also been described, for instance starting with tryptamine rather than indole.[1][2]
References
- ^ a b c Collins M (2011). "Some new psychoactive substances: precursor chemicals and synthesis-driven end-products". Drug Test Anal. 3 (7–8): 404–416. doi:10.1002/dta.315. PMID 21755608.
Obviously, the easiest approach for some simple N,N-dialkyl tryptamines is to begin with tryptamine itself and exhaustively alkylate the primary amino group. An example of this approach is the preparation of N,N-dimethyltryptamine (DMT) shown in Figure 10. Tryptamine is treated with excess methyl iodide and the intermediate quaternary ammonium salt is then reduced to DMT. If however tryptamine is not available or if it is desired to produce more complex tryptamines, i.e. tryptamines containing substituents on the aromatic ring, other approaches may be tried. Starting with indole, or a ring-substituted indole, the Speeter-Anthony synthesis[27] gives good yields of tryptamines. An example of the applicability of this synthesis is [5-MeO-DiPT], whose psychoactive properties are well known. Its synthesis by this method is shown in Figure 11. By varying the amine used in the second step, a variety of tryptamines may be prepared. Generally the Speeter-Anthony approach is an ideal way to produce various tryptamines if indole or a ring-substituted indole is available as the precursor.
- ^ a b c d Appendino G, Minassi A, Taglialatela-Scafati O (July 2014). "Recreational drug discovery: natural products as lead structures for the synthesis of smart drugs". Nat Prod Rep. 31 (7): 880–904. doi:10.1039/c4np00010b. PMID 24823967.
The alternative routes can be broadly divided into two classes, depending on the starting material (indole or substitutes indoles vs. aniline derivatives). One popular route belonging to the first class is based on the venerable Speeter–Anthony synthesis of triptamines (Scheme 20).94 Indole is acylated with oxalyl chloride to 92, next followed by amide 93 formation and global reduction with an excess of LiAlH4 to 94. The hypotensive95 pseudo-benzylic alcohol 95 and its dimerization product 96, whose biological profile is completely unknown, are the most common by-products formed in the reaction, and often contaminate the street drug.
- ^ Shaba, Reham (24 September 2020). "Development of an improved psilocybin synthesis". DIVA. Retrieved 9 November 2025.
The general synthetic approach to psilocybin is presented in scheme 1, where Speeter-Anthony tryptamine synthesis (STS) is performed. STS is a synthetic route whereby a tryptamine is produced from a reaction with an indole and oxalyl chloride followed by a reduction [15]. In [13] an Acylation of 4-hydroxyindole 2 was synthesized, thereafter, STS was applied and resulted into psilocin 5 with 85% yield.
- ^ Speeter, Merrill E.; Anthony, William C. (1954). "The Action of Oxalyl Chloride on Indoles: A New Approach to Tryptamines". Journal of the American Chemical Society. 76 (23): 6208–6210. doi:10.1021/ja01652a113. ISSN 0002-7863. Retrieved 27 November 2025.