Synthesis 2019; 51(14): 2829-2838
DOI: 10.1055/s-0037-1612376
paper
© Georg Thieme Verlag Stuttgart · New York

Microwave-Assisted Cyclization of Unprotected Dipeptides in Water to 2,5-Piperazinediones and Self-Assembly Study of Products­ and Reagents

Marina Kurbasic
a   Chemical & Pharmaceutical Sciences Dept., University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
,
Sabrina Semeraro
a   Chemical & Pharmaceutical Sciences Dept., University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
,
Ana M. Garcia
a   Chemical & Pharmaceutical Sciences Dept., University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
,
Slavko Kralj
a   Chemical & Pharmaceutical Sciences Dept., University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
b   Materials Synthesis Department, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia   Email: smarchesan@units.it
,
Evelina Parisi
a   Chemical & Pharmaceutical Sciences Dept., University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
,
Caterina Deganutti
a   Chemical & Pharmaceutical Sciences Dept., University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
,
Rita De Zorzi
a   Chemical & Pharmaceutical Sciences Dept., University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
,
a   Chemical & Pharmaceutical Sciences Dept., University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
› Author Affiliations
Italian Ministry of University and Research (MIUR) through the Scientific Independence of Young Researchers (SIR) program (‘HOT-SPOT’ project, personal research grant no. RBSI14A7PL to S.M.), Ramón Areces Foundation (A.M.G.’s fellowship), and Beneficentia Stiftung Fundation.
Further Information

Publication History

Received: 03 February 2019

Accepted after revision: 08 March 2019

Publication Date:
25 March 2019 (online)


Published as part of the Bürgenstock Special Section 2018 Future Stars in Organic Chemistry

Abstract

Dipeptides and their cyclized 2,5-piperazinedione (or diketopiperazine, DKP) derivatives are attractive building blocks for supra­molecular hydrogels. The Phe-Phe, (p-nitro)-Phe-Phe, and Phe-Val dipeptides and their corresponding DKPs are studied for self-assembly in water. The DKPs were obtained in high yields by microwave-assisted cyclization­ of the dipeptides in water, demonstrating that use of their methyl ester derivatives as reported in the literature is not necessary for successful cyclization. Single-crystal XRD structures are reported for two DKPs as well as stable hydrogels at neutral pH.

Supporting Information