Synthesis of tryptamines by the Fischer method using synthetic precursors and latent forms of amino-butanal (review)

Abstract

Information on the synthesis of tryptamines using the Fischer reaction is reviewed. A comparative analysis is made of the methods of production and the reactivity of the various synthetic precursors and latent forms of aminobutanal -the carbonyl component in the synthesis of tryptamines by the Fischer method.

Epoxide Opening-Induced Tandem 8-Azabicyclo[3.2.1]octane to 6-Azabicyclo[3.2.1]octane Rearrangement−Iminium Allylation: Synthesis of (±)-Peduncularine

“…Hydroboration/oxidation of the terminal alkene present in alkene 12 gave alcohol 13 (95%), and the derived aldehyde 14 , formed (84%) using cat. TPAP/NMO, was converted into the corresponding 1,3-dioxane 15 (70%), the latter for protection during the next two steps and to potentially improve reaction efficiency in the following Fischer indole reaction . Carbamate deprotection with concomitant desilylation of 1,3-dioxane 15 was achieved using KOH in refluxing i -PrOH to provide a crude amino alcohol, which underwent reductive amination to install the N - i -Pr group giving alcohol 16 (78% yield from 1,3-dioxane 15 ).…”

“…Carbamate deprotection with concomitant desilylation of 1,3-dioxane 15 was achieved using KOH in refluxing i -PrOH to provide a crude amino alcohol, which underwent reductive amination to install the N - i -Pr group giving alcohol 16 (78% yield from 1,3-dioxane 15 ). Fischer indole synthesis , from alcohol 16 furnished indole 17 in 72% yield (Scheme ). Indole 17 (epimeric at the hydroxyl to an intermediate in Roberson and Woerpel’s synthesis) was oxidized under modified Parikh−Doering conditions, to give ketone 18 in 75% yield, completing a formal synthesis.…”