Alessandro Sega

Properties of sesame oil by detailed 1H and 13C NMR assignments before and after ozonation and their correlation with iodine value, peroxide value, and viscosity measurements

Gaseous ozone chemically reacts with unsaturated triglyceride substrates leading to ozonated derivatives with a wide potential applications, ranging from the petrochemical to the pharmaceutical industry. To date, an ultimate understanding of the ozone reactivity during sesame oil ozonation process as well as detailed (1)H and (13)C NMR assignments are lacking. A practical advantage of NMR is that a single NMR sample measurement can explain many issues, while similar analysis by traditional methods may require several independent and time-consuming measurements. Moreover, significant relationships among NMR spectra and both conventional chemical analysis and viscosity measurements have been found. Eventually, NMR could play an important role for quality attributes of ozonated oil derivatives.

1,3-Cycloaddition of nitrile oxides in ionic liquids. An easier route to 3-carboxy isoxazolines, potential constrained glutamic acid analogues

Abstract Several improvements in the cycloaddition of carboethoxyformonitrile oxide (CEFNO) with different alkenes are observed in the ionic liquids [bmim][BF 4 ] and [bmim][PF 6 ]. The possibility of obtaining good yields of the corresponding isoxazolines opens the way towards parallel collections of glutamic acid (Glu) analogues.

NOVEL ANALGESIC/ANTI-INFLAMMATORY AGENTS: 1,5-DIARYLPYRROLE NITROOXYALKYL ETHERS AND RELATED COMPOUNDS AS CYCLOOXYGENASE-2 INHIBITING NITRIC OXIDE DONORS

A series of 3-substituted 1,5-diarylpyrroles bearing a nitrooxyalkyl side chain linked to different spacers were designed. New classes of pyrrole-derived nitrooxyalkyl inverse esters, carbonates, and ethers (7-10) as COX-2 selective inhibitors and NO donors were synthesized and are herein reported. By taking into account the metabolic conversion of nitrooxyalkyl ethers (9, 10) into corresponding alcohols, derivatives 17 and 18 were also studied. Nitrooxy derivatives showed NO-dependent vasorelaxing properties, while most of the compounds proved to be very potent and selective COX-2 inhibitors in in vitro experimental models. Further in vivo studies on compounds 9a,c and 17a highlighted good anti-inflammatory and antinociceptive activities. Compound 9c was able to inhibit glycosaminoglycan (GAG) release induced by interleukin-1β (IL-1β), showing cartilage protective properties. Finally, molecular modeling and (1)H- and (13)C-NMR studies performed on compounds 6c,d, 9c, and 10b allowed the right conformation of nitrooxyalkyl ester and ether side chain of these molecules within the COX-2 active site to be assessed.

Synthesis of furo-furans by rearrangement of 4-acetylpyrans

Abstract The hetero-Diels-Alder reaction of 1-oxabutadienes 1a–c bearing electron-withdrawing groups with ethyl vinyl ether and 2,3-dihydrofuran gave the functionalized 5,6-dihydro-4H-pyrans 2a-c, 4c and 4H-4a, 5, 6, 6a-tetrahydrofuro[2,3-b]pyrans 5a-c and 6c. Cycloadducts 2a and 4c easily rearranged to furo[2,3-b]furans 3a, 3c and 9c and cycloadducts 5a and 6c to difuro[2,3-b:3′,4′-d]furans 7a, 7c and 8c. The stereochemistry of compounds 5c and 7a was determined by single crystal X-ray analysis. Relative configurations of the other compounds were established by nOe data. Some aspects of the reaction mechanisms are discussed.

Influence of the solvent on the stereoselectivity of 1,3-dipolar cycloaddition of nitrile oxides on several 4-substituted 2-cyclopentenones

The diastereofacial selectivity in 1,3-dipolar cycloadditions of 2,6-dichlorobenzonitrile oxide on 2-cyclopentenones 1–5 is strongly dependent on the solvent when an hydroxyl group is present at C(4) (1–2) while if this group is protected (3–4) or absent (5) the reaction is solvent independent.

New multifunctional surfactants from natural phenolic acids.

Several new multifunctional molecules derived from natural sources such as amino acids and hydroxycinnamic acids were synthesized. They exhibit various activities such as emulsifying, UV-protecting, and radical scavenging, thereby conforming to the latest requirements for cosmetic ingredients. The synthesis comprises only a few steps: (i) the amino acid, the acid groups of which are protected by esterification, is coupled with ferulic or caffeic acid; (ii) the p-hydroxyl group of the cinnamic derivative reacts with dodecyl bromide in the presence of potassium carbonate (the resulting compounds are highly lipophilic and tested as water/oil (W/O) emulsifiers); (iii) these molecules, by deprotonating the acid groups of the amino acids, with successive salification, are more hydrophilic, with stronger O/W emulsifying properties. The new multifunctional surfactants might prove useful for the treatment of multiple skin conditions, including loss of cellular antioxidants, damage from free radicals, damage from UV, and others.

COMPARATIVE CONFORMATIONAL AND DYNAMICAL STUDY OF SOME N-QUATERNARIZED UV FILTERS : STRUCTURE-ACTIVITY RELATIONSHIPS

A comparative conformational and dynamical study of a series of structurally related molecules with UV-filtering properties, i.e. N,N-dimethyl-N-[2-(4-benzoyl-2-hydroxyphenoxy)ethyl]-N-dodecyl ammonium bromide 2, N,N-dimethyl-N-[6-(4-benzoylphenoxy)hexyl]-N-dodecyl ammonium bromide 3 and N,N-dimethyl-N-[3-(salicyloylamino)propyl]-N-dodecyl ammonium bromide 5, has been performed in CDCl3 and [2H6] DMSO solutions. The main conformers of 2 and 3 (extensively folded conformations) and 5 (‘linear’ conformations) were determined by means of selective spin-lattice proton relaxation rates, carbon spin-lattice relaxation rates and 1D nuclear Overhauser effects. On the basis of these results a possible correlation between conformation and antibacterial activity is discussed.

[RuII(NO+)]3+-core complexes with 4-methyl-pyrimidine and ethyl-isonicotinate: synthesis, X-ray structure, spectroscopy, and computational and NO-release studies upon UVA irradiation.

The reaction of RuCl(3)(NO).H(2)O with 4-methylpyrimidine (MePYM) and ethylisonicotinate (EINT), in absolute ethanol at 40-55 degrees C afforded crystalline trans-[RuCl(3)(NO)L(2)] complexes. Structural studies via X-ray diffraction, and spectroscopic methods (NMR, IR, UV-visible (UV-Vis)) revealed that the molecular structures have the two Ls in trans positions (axial) and the chloride anions and the NO(+) cation as equatorial ligands; pyrimidine...pyrimidine pairing pattern via two weak C-H...N interactions occur. The molecular structures for the EINT derivative was inferred from spectroscopy and computations. Under irradiation at 366 nm several solutions of the title compounds deliver NO via first order processes. Visible light (420-700 nm) does not produce significant NO release from CH(2)Cl(2) and CH(3)CN solutions within 24h.

Synthesis of enantiopure bis-isoxazolines from (4R)-(+)-4-acetoxycyclopent-2-enone

Abstract (4 R )-(+)-4-Acetoxycyclopent-2-enone was used as a starting material in the stereoselective synthesis of enantiopure bis-isoxazolines.

A new route to highly substituted 1H-pyrrol-3(2H)-ones

Abstract Reaction of 3,4-diacetyl-3-hexen-2,5-dione, 1, with alkyl or aryl primary amines, 2a–g, led to highly substituted 1H-Pyrrol-3(2H)-ones, 3a–g. The structure was established from a single crystal X-ray analysis of compound 3c.