Unexpected racemization of proline or hydroxy-proline phenacyl ester during coupling reactions with Boc-amino acids

The constitution and conformation of the known cyclopeptide alkaloid mauritine-A were determined by X-ray diffraction methods. All amino acids belong to the L-series, 3-hydroxy proline has trans-configuration. As indicated by the UV-spectrum, the 14-membered ring system is considerably strained.

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Synthetic studies of novel ninhydrin analogs

Canadian Journal of Chemistry ◽

10.1139/v01-143 ◽

2001 ◽

Vol 79 (11) ◽

pp. 1632-1654 ◽

Cited By ~ 18

Author(s):

Richard R Hark ◽

Diane B Hauze ◽

Olga Petrovskaia ◽

Madeleine M Joullié

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Cross Coupling ◽

Coupling Reactions ◽

Latent Fingerprints ◽

Cross Coupling Reactions ◽

Essential Tool ◽

Porous Surfaces ◽

Synthetic Studies ◽

Sulfur Containing

Ninhydrin is an essential tool in the analysis of amino acids, peptides, and proteins, and the preferred reagent for the detection of latent fingerprints on porous surfaces. The goal of this investigation was to prepare ninhydrin analogs with enhanced chromogenic and fluorogenic properties. Target compounds included structures with extended conjugation and (or) with the presence of sulfur-containing moieties. We have devised general convergent routes for novel heterocyclic and aryl-substituted ninhydrin analogs for use as reagents for amino acid detection.Key words: ninhydrin analogs, synthesis, ketals, Suzuki cross-coupling reactions, Stille cross-coupling reactions.

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Synthesis of Azido Acids and Their Application in the Preparation of Complex Peptides

Synthesis ◽

10.1055/s-0040-1707314 ◽

2020 ◽

Author(s):

Ryan Moreira ◽

Michael Noden ◽

Scott D. Taylor

Keyword(s):

Amino Acids ◽

Natural Products ◽

Total Synthesis ◽

Cyclic Peptides ◽

Protecting Groups ◽

Side Chain ◽

Coupling Reactions ◽

Protecting Group

AbstractAzido acids are important synthons for the synthesis of complex peptides. As a protecting group, the azide moiety is atom-efficient, easy to install and can be reduced in the presence of many other protecting groups, making it ideal for the synthesis of branched and/or cyclic peptides. α-Azido acids are less bulky than urethane-protected counterparts and react more effectively in coupling reactions of difficult-to-form peptide and ester bonds. Azido acids can also be used to form azoles on complex intermediates. This review covers the synthesis of azido acids and their application to the total synthesis of complex peptide natural products.1 Introduction2 Synthesis of α-Azido Acids2.1 From α-Amino Acids or Esters2.2 Via α-Substitution2.3 Via Electrophilic Azidation2.4 Via Condensation of N-2-Azidoacetyl-4-Phenylthiazolidin- 2-Thi one Enolates with Aldehydes and Acetals2.5 Synthesis of α,β-Unsaturated α-Azido Acids and Esters3 Synthesis of β-Azido Acids3.1 Preparation of Azidoalanine and 3-Azido-2-aminobutanoic Acids3.2 General Approaches to Preparing β-Azido Acids Other Than Azi doalanine and AABA4 Azido Acids in Total Synthesis4.1 α-Azido Acids4.2 β-Azido Acids and Azido Acids Containing an Azide on the Side Chain5 Conclusions

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