Aortic stenting in the growing sheep causes aortic endothelial dysfunction but not hypertension: Clinical implications for coarctation repair

Stent implantation is the treatment of choice for adolescents and adults with aortic coarctation (CoAo). Despite excellent short-term results, 20%-40% of the patients develop arterial hypertension later in life, which was attributed to inappropriate response of the aortic baroreceptors to increased stiffness of the ascending aorta (ASAO), either congenital or induced by CoAo repair. In particular, it has been hypothesized that stent itself may cause or sustain hypertension. Therefore, we aimed to study the hemodynamic and structural impact following stent implantation in the normal aorta of a growing animal

L'Università dell'innovazione. L'ufficio di trasferimento tecnonolgico dell'Ateneo di Cagliari "Unica Laison Office"

Obiettivi ed organizzazzione dell'ufficio per il trasferimento tecnologico

Desymmetrization of α-diimines: Synthesis of new 3-(diaziridin-3-yl) oxaziridines

New heterocyclic compounds characterized by the presence of a diaziridine and an oxaziridine ring directly bound were reported. A first desymmetrization reaction of α-diimines using nosyloxycarbamate as aminating agent in a H2O/CH2Cl2 system gives (E)-3-(iminomethyl) diaziridine-1-carboxylates which were further functionalized obtaining the never synthesized before 3-(diaziridin-3-yl)oxaziridines. © 2013 Elsevier Ltd. All rights reserved

Water-controlled chiral inversion of a nitrogen atom during the synthesis of diaziridines from α-branched N,N'-dialkyl α-diimines

Desymmetrization of chiral α-diimines by ethyl nosyloxycarbamate using water as a co-solvent takes place with very high diastereoselectivity, the nucleophilic attack occurring only on the less hindered side of the CN double bond. Interestingly, the presence of water in the reaction medium likely stabilizes the anion intermediate slowing down the successive cyclization reaction and favoring the rotation around the C-N single bond. In fact, as confirmed by ROESY experiments, only the two diastereomeric 3-(iminomethyl) diaziridine-1-carboxylates that differ in the absolute configuration of the alkyl substituted nitrogen atoms were always obtained in equimolar ratios. Finally, all compounds were easily obtained in optically pure form through HPLC separation and can be considered as interesting chiral synthons. © 2013 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique

Synthesis of gem-diamino acid derivatives by a Hofmann rearrangement

Starting from commercially available N-protected l-alpha-amino acids, N,N'-protected gem-diaminic units were obtained by a two-step methodology. A Hofmann reaction performed using a primary alcohol as the solvent to trap the isocyanate intermediate represents the key step of the new synthetic procedure. Then, the methodology was applied to alpha-carbamoyl alpha'-carboxyl aziridines, also functionalized with l-alpha-amino esters and stable gem-diaminic units characterized by an aziridine ring and by a retro-peptide modification were obtained. The use of the latter units in the retro-peptide chemistry allows to obtain modified peptides containing an aziridine ring able to behave as an electrophilic site and as a biomimetic structural analog of proline

Stereoselective synthesis of short benzyl malonyl peptides

A Rh-catalyzed addition reaction on non symmetric dehydro alanine retro-peptides is the key step in the reported three-step strategy for the diastereoselective synthesis of differently functionalized benzyl malonyl peptides (74% overall yield)

Chiral bidiaziridines by a two-step domino aziridination of meso-α-diimines

Chiral racemic α-diimines, tested in aziridination reactions with NsONHCO2Et, for the first time led to the synthesis of d,l-bidiaziridines, stereoselectively derived from the corresponding meso (E-s-trans-E)-α-diimines. Moreover, a minor bidiaziridine isomer, probably a meso form that was lost under classical work-up conditions, can be obtained by adding water to the crude mixtures at the end of amination reactions. The results definitively prove that the imine aziridination by carbamates is a two-step domino process. The structures of the compounds were determined using 2D NMR on purified bidiaziridine