An efficient protocol for the synthesis of N-fused 2, 5-diketopiperazine via base catalyzed Ugi-type MCR

Abstract

Numerous diversity-oriented synthesis of N-fused cyclic heterocycles have been demonstrated but most of them are based on point diversity within the same library and usually include slow sequential multistep synthesis, which also hurt from low yields and/or poor originator scopes. In current context, an efficient synthesis has been developed with the use of potassium carbonate as base under catalytically free reaction conditions.

2,5-Diketopiperazines via Intramolecular N-Alkylation of Ugi Adducts: A Contribution to the Synthesis, Density Functional Theory Study, X-ray Characterization, and Potential Herbicide Application

“…As observed (Table , entries 4, 12, 34, and 35), the use of bromine as the leaving group for the cyclization step did not result in the increase in the overall yield compared to the use of chlorine. With respect to the cyclization step alone (Scheme ), yields varied between 74 and 99%, values similar or even higher than those obtained for the cyclization stage via intramolecular N -alkylation in previous studies. ,, …”

“…With respect to the cyclization step alone (Scheme 3), yields varied between 74 and 99%, values similar or even higher than those obtained for the cyclization stage via intramolecular N-alkylation in previous studies. 10,15,16 Crystal Structures' Description. The discussion of structures will be divided into two groups.…”

“…A wide variety of 2,5-DKP has been isolated from plants, fungi, bacteria, and mammalian and marine organisms, and many of such compounds have shown promising and relevant biological properties. ,− Their ability to bind a wide variety of biological receptors has been attributed to their conformationally rigid backbone, capable of mimicking preferential peptide conformation, and to the increased stability of the 2,5-DKP core against proteolysis in comparison to acyclic dipeptides, which allows for such drug-like properties. Such biological properties have made 2,5-DKPs promising scaffolds for the development of novel therapeutic agents, leading to the emergence of different methods for obtaining synthetic 2,5-DKPs. − The progress on the synthetic strategies toward 2,5-DKP up to 2012 has been reviewed, but novel strategies have emerged . A classical methodology for the construction of the 2,5-DKP ring consists of the amidation reaction between an activated carboxyl group of an N -Boc-protected amino acid with the amine group of a C -protected amino acid (amino acid ester).…”

Influence of Open Chain and Cyclic Structure of Peptidomimetics on Antibacterial Activity in E. coli Strains

“…al. reported the cyclisation of Ugi peptidomimetic using a transition metal catalyst [ 35 ]. We modified the conditions for our reaction to eliminate the usage of a metal catalyst ( Table 2 , Scheme 3 , Entry 1).…”

Synthesis of Peptidomimetics via IMCR/Post-Transformation Strategy

“…However, recently Marccacini et al reported the ultrasound assisted synthesis in two steps of DKPs via Ugi-4CR followed by basic cyclization reaction under harsh basic conditions (Scheme 1a) [8]. In 2008 Naliapara et al reported an efficient synthesis of DKPs using mild basic and catalysis-free conditions at 100 C (Scheme 1b) [9]. Herein, we report a one-pot strategy for the synthesis of PHP like DKPs.…”