Giuliana Cardillo was born in Anconu, Italy. She received her degree in Chemistrvfrom the University of Rome. Then she moved to the Politecnico of Milan working under Professor A. Quilico on naturally occurring chromenes. After two year5 at the University of Bari she moved to the Department of Chemistry 'G. Ciamician' of the Universiq of Bologna working with Profesmr G. Cainelli on the syntheJi5 of terpenoids. She became ProfeJJor of Organic Chemistry in 1980. Her major re5earch interest5 lie in the area of asymmetric synthesis of polytknctionalized biologically active corripoundh , and the stereo-Jelective 5ynthesiJ of amino acid5 is a recent focus.
Gelators may be divided into chemical gels and physical gels: the internal structure of chemical gels is made of chemical bonds, while physical gels are characterized by dynamic cross-links that are constantly created and broken. The gelator present in physical gels may be an inorganic or an organic compound, the latter having a molecular weight of ≤500 amu. These compounds are generally called "low molecular weight gelators" (LMWGs). In this tutorial review we want to focus our attention on short peptides or peptidomimetics that behave as LMWGs. Peptidomimetics are small protein-like molecules designed to mimic natural peptides. To efficiently design a peptidomimetic, local constraints must be introduced into the skeleton, to induce the formation of preferred secondary structures.
[reaction: see text] The aldol condensation of acetone with several isatins is described. The desired compound was obtained in quantitative yield and with good enantioselectivities up to 77%. The best results were obtained with 10 mol % H-D-Pro-L-beta3-hPhg-OBn as a catalyst, resulting in the preferential formation of the (R)-enantiomer. The absolute configuration of the newly formed chiral center has been assigned by an X-ray diffraction study and CD spectra analysis of the molecules.
It is well assessed that the charge transport through a chiral potential barrier can result in spin-polarized charges. The possibility of driving this process through visible photons holds tremendous potential...
One is enough: The dipeptide Boc‐L‐Phe‐D‐Oxd‐OBn (Boc=tert‐butoxycarbonyl, Phe=phenylalanine, Oxd=4‐methyl‐5‐carboxy oxazolidin‐2‐one, Bn=benzyl; see picture; gray C, white H, red O, blue N) spontaneously forms uniform fibers consisting of parallel infinite linear chains arising from single intermolecular NH⋅⋅⋅OC hydrogen bonds. This is the absolute borderline case of a parallel β‐sheet structure.
[reaction: see text] Contrary to expectations, commercially available 2 M Me2Zn in toluene is able to promote the addition of phenylacetylene to aldehydes and ketones. This reactivity is determined by a new, unprecedented mechanism, which involves activation of the zinc reagent via coordination with carbonyl substrates that behave "ligand like". Broad scope, high tolerance to functional groups, and a simple procedure make this new method highly interesting for the synthetic chemist.
Three sets of oligomers containing the 4-carboxy-5-methyloxazolidin-2-one (Oxd) moiety have been synthesized with the aim of checking whether these molecules are able to fold in ordered structures: A set [Boc-(L-Ala-L-Oxd)(n)-OR], B set [Boc-(L-Ala-D-Oxd)(n)-OR], and C set [Boc-(Aib-L-Oxd)(n)-OR] preferential conformations have been analyzed with IR absorption, NMR, and CD. We have noticed that in these oligomers three stabilizing effects are active: (i) the rigid Oxd -CO-N(CH<)-CO- moiety, which always tend to assume a trans conformation; (ii) the formation of Oxd C=O...H-(alpha)C intramolecolar H-bonds; (iii) the alternate formation of 1 <-- 4 intramolecular C=O...H-N H-bonds. Through the analysis of the experimental data, we could demonstrate that only the oligomers of the B set are able to meet all three requirements listed above. By a deeper insight into the CD spectra, we gathered that the secondary structure adopted by the B set oligomers is a beta-bend ribbon spiral, which is a subtype of the 3(10)-helix.
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