Piperazine-2,5-diones and Related Lactim Ethers

Efficient Microwave Assisted Syntheses of 2,5-Diketopiperazines in Aqueous Media

“…The DKP core derives, chemically and biosynthetically, from folding and head-tail cyclization between N and C -terminal amino acids of linear dipeptides [ 9 ]. These heterocyclic compounds possess two amide groups (with acceptor-donor properties) with the possibility of including up to four hydrogen bonds [ 10 ]. DKPs can be synthesized in solution or in solid phase from commercially available and appropriately protected chiral α-amino acids.…”

“…DKPs can be synthesized in solution or in solid phase from commercially available and appropriately protected chiral α-amino acids. Their syntheses can be carried out with the appropriate linear dipeptide [ 11 , 12 , 13 ], followed by N -deprotection and cyclization using either basic (aminolysis of dipeptide ester in methanolic ammonia, Fischer method) [ 10 , 14 ], neutral (aminolysis of dipeptide ester in methanol, autoaminolysis) [ 15 ], or acidic conditions (Suzuki method) [ 16 ]. Some of these methods variously result in good reaction yields [ 17 ], low reaction yields [ 18 ], with or without epimerization [ 19 ].…”

A C–H Activation Approach to the Tricyclic Core of Glionitrin A and B

“… 1 , 2 Consequently, this motif has been the subject of extensive synthetic efforts. 2 − 4 Natural products containing dithiodiketopiperazines (DTDKPs) have drawn particular interest due to their challenging syntheses and broad spectra of useful biological properties. 5 , 6 A subclass of this natural product family comprises compounds wherein the DTDKP is fused to an indoline at the 2,3-positions.…”

A versatile synthesis of cyclic dipeptides using the stepwise construction of the piperazine-2,5-dione ring from simple precursors: synthetic sequence and the structure of a representative product, (3RS)-4-(2-allyl-3,5-dimethylphenyl)-1-benzyl-3-phenylpiperazine-2,5-dione

“…In view of the biological importance of this type of compound, several synthetic methodologies based on intramolecular cyclizations of appropriate substrates have been developed for their preparation (Rajappa & Natekar, 1993;Dinsmore & Beshore, 2002;Fischer, 2003;Martins & ISSN 2053-2296 # 2018 International Union of Crystallography Carvalho, 2007). Here, and in continuation to our previous studies of the synthetic utility of substituted 2-allylanilines (Palma et al, 2004(Palma et al, , 2010Gó mez Ayala et al, 2006;Orejarena et al, 2014), we report an easy and reproducible synthesis of four new cyclic dipeptides of the type 4-(2-allylaryl)-1-benzyl-3-phenylpiperazine-2,5-dione, (IIIa)-(IIId), which differ only in the identity of the small substituents on one of the benzene rings (see Scheme 1).…”