A bioconjugate approach toward squalamine mimics: Insight into the mechanism of biological action.

A short and efficient synthesis has been devised for a family of squalamine mimics, based on the use of cholic acid, deoxycholic acid, lithocholic acid, putrescine, and spermine as starting materials. Those mimics that contain two facially amphiphilic sterol-spermidine conjugates show strong antibacterial activity against a broad spectrum of Gram-positive bacteria; their corresponding activities against a broad spectrum of Gram-negative bacteria are relatively moderate. Larger mimics, containing four such sterol-spermidine conjugates, exhibit very weak activities.

Hydrogen-bonding-mediated anthranilamide homoduplexes. Increasing stability through preorganization and iterative arrangement of a simple amide binding site.

This paper describes the assembly of two new series of self-complementary duplexes by making use of amide units, the simplest assembling units of hydrogen bonding, as binding sites. All the new monomers possess a rigidified anthranilamide skeleton, which is stabilized by intramolecular hydrogen bonding. Amide units are iteratively introduced to one side of the preorganized skeletons to facilitate the formation of intermolecular hydrogen bonding.

Hydrogen-bonding-driven preorganized zinc porphyrin receptors for efficient complexation of C60, C70, and C60 derivatives.

This paper describes the self-assembly of a new class of foldamer-based molecular tweezers, whose rigid folded conformations are stabilized by intramolecular hydrogen bonding. Two zinc porphyrin units are introduced to the ends of molecular tweezers Zn(2)1 and Zn(2)2, while three zinc porphyrin units are incorporated to the S-shaped bi-tweezers Zn(3)3, which may be regarded as a combination of two Zn(2)1 molecules. Due to the preorganized U-shaped feature, Zn(2)1 and Zn(2)2 are able to strongly complex C60, C70, and C60 derivative 25 in chloroform or toluene in a 1:1 binding stoichiometry, whereas Zn(3)3, which possesses two tweezer units, complexes the guests in a 1:2 stoichiometry.

Poly(choloyl)-based amphiphiles as pore-forming agents: transport-active monomers by design.

This paper describes the design and synthesis of a family of pore-forming amphiphiles. Two of these amphiphiles, which are derived from cholic acid, lysine, and p-phenylenediamine, can produce pores in lipid bilayers as individual molecules. In sharp contrast, analogous amphiphiles that do not contain a rigid 1,4-phenylenediamide moiety favor the formation of dimer-based pores.

Hydrogen bonded oligohydrazide foldamers and their recognition for saccharides.

This paper describes the synthesis and characterization of the first series of hydrogen bonding-driven hydrazide foldamers and their recognition for alkyl saccharides in chloroform. Oligomers 1, 2-4, 5, 6, and 7, which contain one, two, four, six, or twelve repeated dibenzoyl hydrazide residues, respectively, have been prepared. The rigid and planar conformations of 1 and 2 or 4 have been established with X-ray analysis and (1)H NMR spectroscopy, whereas the folding and helical conformations of 5-7 have been evidenced by the 1D and 2D (1)H NMR and IR spectroscopy and molecular mechanics calculations.

Recognition through self-assembly. A quadruply-hydrogen-bonded, strapped porphyrin cleft that binds dipyridyl molecules and a [2]rotaxane.

Quadruply-hydrogen-bonded porphyrin homodimer Zn1.Zn1 has been designed, assembled, and evaluated as a supramolecular cleft-featured receptor for its ability to bind dipyridyl guests in chloroform-d. Monomer Zn1 consists of a 2-ureidopyrimidin-4(1H)-one unit, which was initially reported by Meijer et al.

Selective rearrangements of quadruply hydrogen-bonded dimer driven by donor-acceptor interaction.

A general method has been developed to control the selective rearrangement of Meijer's AADD quadruply hydrogen-bonded homodimers by introducing an additional donor-acceptor interaction. Therefore, one donor-assembling monomer, 1, in which the electron-rich bis(p-phenylene)-34-crown-10 moiety is connected to the hydrogen-bonding moiety, and two acceptor-assembling monomers, 2 and 3, in which the electron-deficient pyromellitic diimide or naphthalene diimide group is incorporated, respectively, are synthesized and characterized. 1H NMR and 2D-NOESY studies show that all these compounds exist as stable homodimers in chloroform.

First zipper-featured molecular duplexes driven by cooperative donor-acceptor interaction.

[structure: see text] The first class of zipper-shaped artificial duplexes, which are driven by multiple donor-acceptor interactions between electron-rich 1,5-dioxynaphthalene or 1,4-dioxybenzene and electron-deficient pyromellitic dimide units, have been studied in organic media by (1)H NMR, UV-vis, and vapor pressure osmometry. (1)H NMR binding investigations reveal substantial cooperativity of the donor-acceptor interaction in the duplexes.