Design and Synthesis of Triazole based Peptidomimetic Macrocycles and other Heterocycles: Studies on the Self-Assembly and Anion Binding Property of the Macrocycles

describes a literature review on several classes of cyclic peptide nanotubes based on cyclic D-,L-,α-peptides, cyclic D-,L-,α,γ peptides and also cyclic-β-peptides. It is focused on macrodipole modification of cyclic peptides by substituting an amide functional group with a perfect mimic of peptide bond to access more effective artificial ion channels. The major point that came out in this regard was that (1,4)-linked triazole shares a number of features with peptide bond in terms of bond-distance, planarity, H-bond accepting as well as donating ability. This review also contains a short discussion of the basic information about the advantage of D-glucose derived cis-β-furanoid sugar moiety which has desired structural features to allow the product to attain a conformation conducive for self assembly. The second part of this chapter describes the construction of two types of novel heterocyclic backbone modified macrocyclic peptides by incorporation of an α-amino acid/β-amino acid with cis-β-furanoid (1,4)-linked triazole amino acid. The macrocyclic peptides featuring α- amino acids are able to maintain pseudo cyclo-β-peptide conformation, while that based on β- amino acid forms only a conformationally homogeneous cyclic peptide. One of the cyclic peptides is able to undergo parallel homo-stacking via amide NH and amide carbonyl oxygen H-bonding like cyclo-β-peptides

Tandem One Pot Synthesis of 1,5-Benzodiazocine-2-one by Isocyanide Based Ugi Multicomponent Reaction

We have developed an efficient one-pot, two-step reaction protocol for the synthesis of eight-membered 1,5-benzodiazocine-2-ones by Ugi four-center three-component coupling reaction (U-4C-3CR) and subsequent reductive cyclization using Fe/NH4Cl in protic solven

Synthesis, Characterization, and Antibacterial Activities of High-Valence Silver Propamidine Nanoparticles

Diabetic foot ulcer (DFU) is becoming more serious concern as it affects 95% of diabetic patients worldwide. It has been shown that the Staphylococcus aureus and other Gram-negative microorganisms are the main reasons behind this disease. Though many antibiotics are presently used to treat the DFU, due to increased bacterial resistance, new alternative therapies are always welcome. To address this alarming issue, we have designed and synthesized the high-valence silver propamidine (Ag(II)PRO) complex as well as nanoparticles and characterized both by usual spectroscopic methods. The reverse microemulsion technique has been applied to synthesize Ag(II)PRO nanoparticles and its antibacterial activity has been compared with zero-valence silver nanoparticles (AgNPs) with similar size. The antibacterial efficacies of Ag(II)PRO nanoparticles and AgNPs were tested against Gram-negative and Gram -positive organisms responsible for DFU. The newly synthesized high-valence Ag(II)PRO nanoparticles showed higher antibacterial activity compared to silver-only nanoparticles (AgNPs). This study concludes that the high-valence Ag(II)PRO nanoparticles show better antibacterial activity than AgNPs and they may serve as the next generation therapeutic agent for the diabetic wound care

Simultaneous Parallel and Antiparallel Self-Assembly in a Triazole/Amide Macrocycle Conformationally Homologous to D-,L-r-Amino Acid Based Cyclic Peptides: NMR and Molecular Modeling Study.

A 1,4-linked triazole/amide based peptidomimetic macrocycle, synthesized from a triazole amide oligomer of cis-furanoid sugar triazole amino acids, possesses a conformation resembling the D-,L-R-amino acid based cyclic peptides despite having uniform backbone chirality. It undergoes a unique mode of self-assembly through an antiparallel backbone to backbone intermolecular H-bonding involving amide NH and triazole N2/N3 as well as parallel stacking via amide NH and carbonyl oxygen H-bonding, leading to the formation of a tubular nanostructure

A Ugi Straightforward Access to Bis-β-lactam Derivatives

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