The synthesis of a new class of cyclic peptidomimetics containing 5‐aminothiophene subunits in their backbone is presented. A modified Gewald reaction was applied as a key step in the synthesis of the thiophene amino acid that was used as a building block in the synthesis of linear oligomers by using standard peptide coupling protocols. Macrocyclization was achieved under high dilution by using EDCI as a coupling reagent. The conformations of an acyclic dimer and a cyclic tetramer were determined by X‐ray crystallographic analyses.

No abstract

No abstract

No abstract

A new multicomponent synthesis of 2-aminothiophene carbocyclic acids 4 by reaction of methyl 2-siloxycyclopropanecarboxylates 1, alkyl cyanoacetates, and elemental sulfur is reported. This version of the Gewald thiophene synthesis rapidly provides a new type of d-amino acids, which can be considered as dipeptide analogues. Smooth protective-group manipulations allowed regioand chemoselective couplings with L-phenylalanine derivatives furnishing new tripeptide analogues such as 5 and 8 or products of type 10.