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Updated: Jun 14, 2025

Facile Protocol for the Synthesis of Self-assembling Polyamine-based Peptide Amphiphiles PPAs and Related Biomaterials
Published on: June 25, 2018
Metal-Free, PPA-Mediated Fisher Indole Synthesis via Tandem Hydroamination-Cyclization Reaction between Simple
Alexander V Aksenov1, Dinara C Makieva1, Rodion A Arestov1
1Department of Chemistry, North Caucasus Federal University, 1a Pushkin St., 355017 Stavropol, Russia.
Abstract:
A new variant of Fisher indole synthesis involving Bronsted acid-catalyzed hydrohydrazination of unactivated terminal and internal acetylenes with arylhydrazines is reported. The use of polyphosphoric acid alone either as the reaction medium or in the presence of a co-solvent appears to provide the required balance for activating the C-C triple bond towards the nucleophilic attack of the hydrazine moiety without unrepairable reactivity loss of the latter due to competing amino group protonation. Additionally, the formal hydration of acetylenes to the corresponding ketones occurs under the same conditions, making it an alternative approach for generating carbonyl groups from alkynes.
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