Synthesis of (macro)heterocycles by consecutive/repetitive isocyanide-based multicomponent reactions

• Angélica de Fátima S. Barreto and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2019, 15, 906–930, doi:10.3762/bjoc.15.88

• products has been reviewed [15][16] and this review will focus only on IMCRs. Consecutive IMCRs Synthesis of small-ring heterocycles (tetrazoles, ketopiperazines, imidazoles, imidazolines and thiazoles) The use of consecutive Ugi reactions in the synthesis of heterocycles was first described in 2001 by Ugi

• mixture of diastereomers). Recently, our research group [22] carried out the synthesis of bis(1,5-disubstituted tetrazoles) 14 using two consecutive Ugi reactions (Scheme 4). The synthetic strategy was based on two hydrazino-Ugi-azide reactions and a hydrazinolysis step for the synthesis of acylhydrazino

• bis(1,5-disubstituted tetrazoles). Methyl isocyanoacetate 13a was used as an essential component in the first hydrazino-Ugi-azide reaction allowing consecutive Ugi reactions to take place. In the first step, 13a, hydrazides, aldehyde or ketone, trimethylsilyl azide (TMSN3) and ZnCl2 (10 mol %) in

Consecutive hydrazino-Ugi-azide reactions: synthesis of acylhydrazines bearing 1,5-disubstituted tetrazoles

• Angélica de Fátima S. Barreto,
• Veronica Alves dos Santos and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2017, 13, 2596–2602, doi:10.3762/bjoc.13.256

• . The products synthesized herein contain functional groups within their structures that can be easily modified to obtain new acylhydrazino 1,5-disubstituted tetrazoles. Keywords: acylhydrazines; consecutive Ugi reactions; 1,5-disubstituted tetrazoles; isocyanide-based multicomponent reactions (IMCRs

Synthesis of acylhydrazino-peptomers, a new class of peptidomimetics, by consecutive Ugi and hydrazino-Ugi reactions

• Angélica de Fátima S. Barreto,
• Veronica Alves dos Santos and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2016, 12, 2865–2872, doi:10.3762/bjoc.12.285

• peptidomimetics with potential biological activity. Keywords: acylhydrazino-peptomers; consecutive Ugi reactions; peptide-peptoid hybrid; peptomer; Introduction In the last decades, increasing efforts have been extensively carried out to improve the pharmacological properties of natural peptides by structural

• (ester hydrolysis and/or Boc deprotection) allows subsequent Ugi or hydrazino-Ugi reactions to further elongate the peptomers main chain. Conclusion In summary, we have developed a concise protocol for the synthesis of functionalized acylhydrazino-peptomers by consecutive Ugi reactions. The general route

Consecutive isocyanide-based multicomponent reactions: synthesis of cyclic pentadepsipeptoids

• Angélica de Fátima S. Barreto,
• Otilie E. Vercillo,
• Ludger A. Wessjohann and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2014, 10, 1017–1022, doi:10.3762/bjoc.10.101

• explored yet. In this paper, we describe the synthesis of six pentadepsipeptoid analogues of San A (Figure 3). The synthetic route for the synthesis of cyclic pentadepsipeptoids via consecutive Ugi reactions allows only three side chains connected to three nitrogen atoms. The pentapeptide of San A has in