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From amines to diketopiperazines: a one-pot approach

2010-03-31, O'Reilly, Elaine, Pes, Lara, Paradisi, Francesca

An efficient one-pot synthesis is described for the preparation of 1,4-disubstituted piperazine-2,5-diones starting from a suitable amine and chloroacetyl chloride in the presence of an aqueous base. The resulting chloroacetamide is cyclised in situ by employing the phase-transfer (PT) catalyst, benzyltriethylammonium chloride (TEBA). The products are isolated in excellent yields of up to 90%.

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A stereoselective synthesis of α-deuterium labelled (S)-α-amino acids

2010, O'Reilly, Elaine, Balducci, Daniele, Paradisi, Francesca

An atom-efficient and stereoselective synthesis has been developed for the preparation of a-2H-labelled(S)-a-amino acids, starting from a novel chiral diketopiperazine scaffold. Efficient mono-alkylation of the chiral template afforded the (S)-substituted adducts with the nature of the electrophile significantly effecting the stereochemical outcome. Subsequent alkylation was totally selective producing the 1,4-cis adduct as the sole diastereoisomer. The deprotection was carried out using cerium ammonium nitrate followed by acid hydrolysis affording the enantipure a-amino acids.

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Synthesis of a conformationally constrained delta-amino acid building block

2013-02, O'Reilly, Elaine, Pes, Lara, Ortin, Yannick, Müller-Bunz, Helge, Paradisi, Francesca

Conformationally restricted amino acids are important components in peptidomimetics and drug design. Herein, we describe the synthesis of a novel, non-proteinogenic constrained delta amino acid containing a cyclobutane ring, cis-3(aminomethyl)cyclobutane carboxylic acid (ACCA). The synthesis of the target amino acid was achieved in seven steps, with the key reaction being a base induced intramolecular nucleophilic substitution. A small library of dipeptides was prepared through the coupling of ACCA with proteinogenic amino acids.

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One-step diketopiperazine synthesis using phase transfer catalysis

2009-04-15, O'Reilly, Elaine, Lestini, Elena, Balducci, Daniele, Paradisi, Francesca

A simple and efficient one-step procedure is described for the synthesis of a number of symmetrical 1,4-disubstituted piperazine-2,5-diones under phase transfer conditions. The reactions are carried out at room temperature, starting from a suitable N-chloroacetamide in the presence of an aqueous solution of sodium hydroxide. Piperazine-2,5-diones were obtained with excellent selectivity in yields of up to 90%.