Efficient Macrocyclization of Preorganized Palindromic Oligosquaramides

Abstract

Nature has evolved polymers with highly specific functions. In the last decade, a new generation of natural circular proteins has been found in bacteria, plants, and mammals.[1] These large cycles show exceptional stability and a wide range of [*] Dr.

An analytical method for prohexadione in Chinese cabbage and apple

“…In fact, at sub‐ambient temperatures both the anti – anti and anti – syn ( syn – anti ) isomers are detected by 1 H NMR spectroscopy 21. We also demonstrated that the inclusion of tertiary amino groups as hydrogen bond donors in the vicinity of the squaramido NH groups induces formation of β‐turn analogues in secondary squaramides, allowing the synthesis of oligomeric cyclosquaramides through hydrogen‐bond‐directed macrocyclization 22…”

Mechanism of Action of Cyclic Oligosquaramides on DPPC Phospholipid Monolayers

“…Oligosquaramides C2 and C5 were synthesized as reported previously. [13] The stock solutions of oligosquaramides were obtained as follows: 60 mg were dissolved in 70 mL of HCl 3 m. The resultant solution is diluted up to a final volume of 500 mL in DMSO. Total clarity of the solution was achieved typically with soft heating (T < 60 8C) for a few minutes.…”

“…Cyclic oligosquaramides have been synthesized successfully by Rotger et al, [13] showing antitumoral activity, as well as inhibition of kinases, with low toxicity.…”

“…In fact, the ability of the oligosquaramides to from intramolecular H bonds in bulk solution leads to a molecular conformation resulting in a cyclic structure. [13] Thus, no conformational change of the oligosquaramide C5 is induced upon interaction with the lipids.…”

Synthesis and structural features of chiral cyclic squaramides and their application in asymmetric catalytic reaction

“…In particular, the diamido-derivatives (also known as squaramides) have been studied in the conttext of molecular recognition, 13 supramolecular assemblies, 14,15 and as improved chiral organocatalysts. These properties have been applied to enhance the biological activity of several drugs and to functionalize organic molecules.…”