Synthesis of C3-Substituted 4-Azaindoles: An Easy Access to 4-Azamelatonin and Protected 4-Azatryptophan

Tailor-Made Amino Acids in Pharmaceutical Industry: Synthetic Approaches to Aza-Tryptophan Derivatives

Over the recent years there has been a noticeable upsurge of interest in aza-analogs of tryptophan which are isosteric to the latter and found numerous applications in medicinal, bioorganic chemistry, and peptide research. In the present review article, five aza-tryptophan derivatives are profiled, including aza-substitution in the positions 2, on the five-membered ring, as well as in positions 4, 5, 6, and 7 on the six-membered ring. A detailed and comprehensive literature overview of the synthetic methods for the preparation of these aza-tryptophans is presented and general facets of the biological properties and most promising applications are discussed.

Straightforward protocol for the efficient synthesis of varied N(1)-acylated (aza)indole 2-/3-alkanoic acids and esters: optimization and scale-up

A library of approximately 40 N(1)-acylated (aza)indole alkanoic esters and acids was prepared employing a microwave-assisted approach. The optimized synthetic route allows for parallel synthesis, variation of the indole substitution pattern and high overall yield. Additionally, the procedure has been scaled up to yield multi-gram amounts of preferred indole compounds, e.g.: 2'-des-methyl indomethacin 2. The reported compounds were designed as biomedical tools for primary and secondary in vitro and in vivo studies at relevant molecular targets.