Structural study of ribonucleotide reductase inhibitor hydrazones. Synthesis and X-ray diffraction analysis of a copper(II)-benzoylpyridine-2-quinolinyl hydrazone complex.

Single crystals as yellow needles of N-(4,8-dimethyl-quinolin-2-yl)-N'-(1-pyridin-2-yl-ethylidene)-hydrazine, HL(1), 1, and N-(4-methyl-quinolin-2-yl)-N'-(phenyl-pyridin-2-yl-methylene)-hydrazine, HL(2), 2, were obtained from methanol (MeOH) and analyzed via X-ray diffraction (XRD). HL(2) reacted with copper(II) acetate to produce a dark red powder that gave single crystals of [Cu(L(2))(OOCCH(3))].0.9C(6)H(5)CH(3), 3.0.9C(6)H(5)CH(3) when recrystallized from toluene. The conformation of the N(quinolinyl,q)-C(q)-N(H)-N(imine,i)-C-C(pyridine,p)-N(p) grouping is trans,trans,trans,trans or tttt, and ttcc for 1 and 2, respectively, at the solid state, as revealed via single crystal X-ray diffraction. Thus, the structure of 1 has the methyl (hydrazone) group syn to the N-H bond and syn to the N(q) and N(p) atom. On the other side, the structure of 2 is stabilized by a strong intra-molecular N-H...N hydrogen bond which involves the pyridyl nitrogen atom. The molecule 1 is almost planar, the torsion angles do not deviate more than 4 degrees from the idealized values of 0 degrees and 180 degrees . In the structure of 2 the pyridyl ring is almost coplanar with the N(q)-C(q)-NH-N(i)-C system, whereas the phenyl (Ph) ring is twisted by ca. 55 degrees . The structure of 3 has the L(2) ligand as deprotonated at the N-N function and in a cttc conformation as opposite to the ttcc one found for pure 2. The metal center is coordinated through N(q), N(i), N(p) and through an oxygen atom from a carboxylate anion. The molecular modeling analysis of 1 and 2 (semi-empirical molecular orbital at Zerner's intermediate neglect of differential overlap (ZINDO/1) level and density functional theory (DFT) methods) gave good agreement with the X-ray structures. Semi-empirical quantum mechanics analysis of 3 allowed to assign the UV-Vis spectrum that is characterized by strong absorptions in the visible, UVA and UVB regions. Owing to the ribonucleotide reductase inhibitory activity of the ligand, to the ascertained anticancer activity shown previously by related copper(II)-hydrazone complexes, and to the oxygen radical scavenger activity of several copper(II)-complexes, 3 is potentially anticancer and anti-inflammatory.

Ionic liquid as a suitable phase for multistep parallel synthesis of an array of isoxazolines.

[reaction: see text]. A parallel array of isoxazoline diamides was prepared using an ionic liquid [bmim][BF4] as the phase where a three-step procedure (Schotten-Baumann, 1,3-dipolar cycloaddition, ester amidation with Me3Al) was carried out. At the end, selective extraction of the final products with diethyl ether allowed simple isolation of the 16 components of the array (Syncore technology).

Antioxidant activity of ferulic acid alkyl esters in a heterophasic system: a mechanistic insight.

The antioxidant activity of some esters of ferulic acid with the linear fatty alcohols C7, C8 (branched and linear), C9, C11, C12, C13, C15, C16, and C18 has been studied in homogeneous and heterogeneous phases. Whereas in homogeneous phase all of the alkyl ferulates possessed similar radical-scavenging abilities, in rat liver microsomes they showed striking differences, the more effective being C12 (7) (IC50 = 11.03 M), linear C8 (3) (IC50 = 12.40 microM), C13 (8) (IC50 = 18.60 microM), and C9 (5) (IC50 = 19.74 microM), followed by C7 (2), C15 (9), C11 (6), branched C8 (4), C16 (10), and C18 (11) (ferulic acid was the less active, IC50 = 243.84 microM). All of the molecules showed similar partition coefficients in an octanol-buffer system. Three-dimensional studies (NMR in solution, modeling in vacuo) indicate that this behavior might be due to a different anchorage of the molecules with the ester side chain to the microsomal phospholipid bilayer and to a consequent different orientation/positioning of the scavenging phenoxy group outside the membrane surface against the flux of oxy radicals.

Conformational analysis: a tool for the elucidation of the antioxidant properties of ferulic acid derivatives in membrane models.

With the aim to search and design more effective and safe antioxidant molecules to be used as functional ingredients in cosmetic formulations for UV protection, we evaluated the antioxidant/radical scavenging activities of ferulic acid and of some alkyl ferulates in both acellular and cellular systems. Ferulic acid esters, equipotent as antioxidant in homogeneous phase, showed when tested in membranous systems (rat liver microsomes, rat erythrocytes) marked differences in antioxidant potency. The n-C(12) derivative was the most potent, followed by n-C(8), n-C(16) and branched C(8), and then by ferulic acid. A conformational study carried out by NMR and modelling, indicates that the different antioxidant activity of ferulates in membrane models is due to the different spatial conformation and arrangement of the side chain of the molecule, which governs the access and binding to the phospholipid bilayer, the modality of orientation of the scavenging/quenching nucleus (phenol moiety), and hence the overall antioxidant potency of the derivative. These results emphasize the need of analytical studies (NMR and molecular modelling) addressed to the knowledge of the conformational parameters in combination with conventional antioxidant testings for understanding the antioxidant behaviour of a molecule in a biological membrane/system.

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-1ß (IL-1ß), 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.

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.

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.

New platinum-oxicam complexes as anti-cancer drugs. Synthesis, characterization, release studies from smart hydrogels, evaluation of reactivity with selected proteins and cytotoxic activity in vitro.

The reaction of aqueous cis-[Pt(NH(3))(2)(H(2)O)(2)](NO(3))(2) with Na(+)HMEL(-) (H(2)MEL, meloxicam, 4-hydroxy-2-methyl-N-(5-methyl-1,3-thiazol-2-yl)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide), and Na(+)HISO(-) (H(2)ISO, isoxicam, 4-hydroxy-2-methyl-N-(5-methylisoxazol-3-yl)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide) at pH 7 produced micro-crystalline cis-[Pt(NH(3))(2)(N(1')-HMEL)(2)], 5 and cis-[Pt(NH(3))(2)(N(1')-HISO)(2)], 6. The X-ray diffraction structure of 5 shows two HMEL(-) anions donating through the thiazole nitrogen atoms and adopting a head-to-tail (HT) conformation. The (1)H NMR spectrum for 5 from DMSO-d(6) shows inertness of the complex up to at least 24h. Delivery studies for 5 and 6 from vinyl hydrogel based on L-phenylalanine (pH 6.5, 25 degrees C) show that concentrations of complexes ranging between 2.5 and 5 microM can be reached after a day. Compounds 5 and 6 show strong anti-proliferative effects on CH1 cells (ovarian carcinoma, human) in vitro, IC(50) values being 0.60 and 0.37 microM, respectively (0.16 microM for reference, cis-diamminodichloridoplatinum(II), cisplatin). ESI-MS measurements clearly documented that both 5 and 6 form adducts with the three model proteins ubiquitin (UBI), cytochrome c (CYT C) and superoxide dismutase (SOD), the HISO(-) complex being significantly more effective than the HMEL(-) one. Density functional methods help in finding rationale for the easiest dissociation of Pt-H(2)ISO/HISO bonds when compared to the Pt-N(1)(')-H(2)MEL/N(1)(')-HMEL linkages.

[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.

Sensible improvements induced by ionic liquids in the reaction of modified carbasugars with bases for the building of constrained carbanucleosides.

Starting from racemic 4-hydroxy-4-methyl-2-cyclopentenone, a family of enantiopure carbanucleosides locked in the northern conformation has been synthesized. The use of ionic liquids was determinant in the last step resulting in a tangible increase of the yields and dramatic reduction of reaction times and volumes of organic solvents. To our knowledge, this is the first example of the use of ionic liquids in the coupling of carbasugars with heterocyclic bases.