Juan M. Fernández-G

The structures of some ortho-hydroxy Schiff base ligands

Abstract Nine ortho-hydroxy Schiff base ligands, (1)–(9), were synthesized and characterized by chemical analysis, mass spectrometry, 1H and 13C NMR spectroscopy. The crystal and molecular structures of compounds (1), (3), (5), (7), (8) and (9) were determined. The solid state X-ray diffraction studies show that compounds (5) and (8) are in the keto–amine tautomeric form, while (1), (3), (7) and (9) are found as phenol–imine tautomers. Moreover, studies in the solution phase by 1H and 13C NMR spectroscopy indicate that compounds (2), (5) and (8) are found as keto–amine tautomers, while (1), (3), (4), (6), (7) and (9) are found as phenol–imine tautomers. Furthermore, ab initio calculations at the HF/6-31G∗ level with full optimization of geometry, performed for both tautomers of (1) and (5), agree with the observed behavior in solution and solid state of these compounds.

Reduction of no-reflow and reperfusion injury with the synthetic 17β-aminoestrogen compound Prolame is associated with PI3K/Akt/eNOS signaling cascade.

A high proportion of primary percutaneous coronary interventions performed in the setting of acute myocardial infarction, concur with inadequate myocardial perfusion at the microvascular level. This phenomenon, known as “no-reflow” contributes to reperfusion injury, poor prognosis and to unfavorable clinical outcome. In this study, we evaluated the hypothesis that the synthetic 17β-aminoestrogen Prolame, may confer cardioprotection and prevent against no-reflow. In an open-chest model of 30-min ischemia and 90-min reperfusion, male Wistar rats were randomly assigned to different groups: Control, Prolame, Prolame followed by the nitric oxide synthase inhibitor (l-NAME), and 17β-estradiol. Areas of risk, infarct size and no-reflow were determined by planimetry with triphenyltetrazolium chloride and thioflavin-S stains. Structural damage of the vasculature was measured as capillary compression in clarified tissue after intra-atrial injection of Microfil. Hemodynamic function was obtained at the end of stabilization, ischemia and reperfusion; nitric oxide (NO·) content was determined indirectly using the Griess reaction. Activation of the eNOS signaling cascade was determined by western blot. Prolame reduced the infarcted area, decreased the zones of no-reflow and capillary compression by activating the PI3K/Akt/eNOS signaling pathway in correlation with NO· increase. Prolame also activated endothelial cells augmenting NO· production, which was inhibited by ICI182780 (a selective estrogen receptor down-regulator), supporting the notion that the cardioprotective effect of Prolame involves the preservation of endothelium through the activation of estrogen receptor downstream signaling. Our results provide evidence that Prolame has potential therapeutic application in patients with AMI, as it prevents from both vascular and cardiac tissue damage.

Electrochemical studies of copper(II) complexes derived from bulky Schiff bases. The crystal structure of bis[N-(1- adamantyl)-salicylaldiminato]copper(II)

Three Schiff base ligands and their corresponding copper(II) complexes have been prepared and characterized. Elemental analyses, mass spectra, i.r., electronic spectra, μeff and the X- ray crystal structure for one of the complexes, as well as elemental analyses, mass spectra, i.r., electronic and 1H n.m.r. spectra of the ligands, have been obtained. The X-ray study shows that the geometry around the metal atom is intermediate between square planar and tetrahedral. Electrochemical studies on the complexes reveal a dependence of the CuII/CuI potentials on the extent of distortion of the planar structure observed in solid state.

Crystal structures and voltammetric behavior of three copper(II) complexes derived from bulky Schiff bases

Three Schiff base copper(II) complexes have been prepared and characterized by elemental analysis, mass spectra, i.r., electronic spectra, μeff and X-ray crystal structures. Cyclic voltammetry studies on the complexes indicate a dependence of the cathodic potentials upon electronic effects, but independence on the solid state structure.

Synthesis and molecular structure of prolame, N-(3-hydroxy-1,3,5(10)-estratrien-17β-yl)-3-hydroxypropylamine; an amino-estrogen with prolonged anticoagulant and brief estrogenic effects

The synthesis and molecular structure of prolame, N-(3-hydroxy-1,3,5(10)-estratrien-17 beta-yl)-3-hydroxypropylamine, is described. It was characterized by ir, nmr, mass spectrometry and chemical analysis. The crystal structure of this compound was determined by single-crystal x-ray diffraction. Prolame belongs to space group P212121. Cell dimensions are: a = 8.356(2), b = 13.343(4) and c = 16.119(4) A. Z = 4; R = 4.1%.

Comparative effect of synthetic aminoestrogens with estradiol on platelet aggregation

The in vitro effect upon platelet aggregation of estradiol and synthetic estrogens (prolame, buame, and proacame) is described. Prolame and buame produced a dose-dependent inhibition on platelet aggregation. Estradiol and proacame did not show anti-aggregating effects. The results suggest that the use of prolame and buame in estrogen therapy could reduce the risk of thrombo-embolic accidents.

Prolame ameliorates anxiety and spatial learning and memory impairment induced by ovariectomy in rats

N-(3-hydroxy-1, 3, 5 (10) estratrien-17beta-yl)-3-hydroxypropylamine (17β aminoestrogen, prolame) is a steroidal compound with weak estrogen-related trophic-proliferative effects in uterus. Contrasting with 17β-estradiol (E2) pro-coagulant effects, this compound has high anticoagulant and antiplatelet effects. It has been extensively demonstrated that E2 plays important roles in brain function. However, prolames influence on central nervous system has not been documented. In this study, we evaluated the effects of prolame replacement in young ovariectomized rats on spatial learning and memory and anxiety, correlating pyramidal cell dendritic spine density changes and neuronal nitric oxide synthase (nNOS) expression in the hippocampus. Ovariectomized young rats were treated with prolame for 4 weeks. Three other groups were used as physiological, pathological, and pharmacological references as follow: gonadally intact cycling females, ovariectomized, and ovariectomized with 17β-estradiol treatment respectively, for the same time period. Experiment 1 investigated the behavioral effects of prolame on anxiety and spatial learning using elevated plus maze (EPM) and Morris water maze (MWM) paradigms respectively. Experiment 2 studied the dendritic spine density and neuronal nitric oxide synthase expression in the hippocampus of the 4 experimental groups. Similar to estradiol, prolame reversed the anxiogenic effects of ovariectomy, evaluated by EPM, and enhanced MWM performance to the level of gonadally intact subjects. Hippocampi from prolame-treated rats exhibited enhanced nNOS immunoreactivity and its relocation in dendritic compartments, as well as recovery of dendritic spine density loss in pyramidal neurons. Hence, prolame may provide an alternative option for ameliorating neurological symptoms caused by surgical menopause.

The crystal structures and electrochemical studies of three 2,3-naphthalenic Schiff base copper(II) complexes

Abstract The Schiff base ligands, 2-hydroxy-N-cyclohexyl-l-naphthaldimine (I), and 3-hydroxy-N-cyclohexyl-2-naphthaldimine (II), and their corresponding CuII complexes (1–2) respectively were synthesized and characterized. The crystal and molecular structures of bis-{(cyclohexyl)[(2-oxo-1H-naphth-1-ylidene)-methyl]aminato}copper(II) (1) and bis-{(cyclohexyl)[(3-oxo-2H-naphth-2-ylidene)-methyl]aminato} copper(II) (2), were determined. The X-ray diffraction study shows that the geometry around the metal atom for (1), is stepped square planar with a step of 1.063 A while for (2), the geometry around the metal atom for square planar with an angle between the coordination planes O(1)CuN(1) and O(1a)CuN(1a) of 39.9°. Electrochemical studies show a dependence of the CuII/CuI potentials on the ligand structure.

Neuroprotective effect of the aminoestrogen prolame against impairment of learning and memory skills in rats injected with amyloid-β-25-35 into the hippocampus.

Alzheimers disease (AD) is a neurodegenerative disorder caused by the deposition of the amyloid-beta peptide (Aβ) in senile plaques and cerebral vasculature. Its neurotoxic mechanisms are associated with the generation of oxidative stress and reactive astrogliosis that cause neuronal death and memory impairment. Estrogens reduce the rate of Azheimers disease because of their antioxidant activity. Prolame (N-(3-hydroxy-1,3,5(10)-estratrien-17β-yl)-3-hydroxypropylamine) is an aminoestrogen with estrogenic and antithrombotic effects. In our study we evaluated the role of prolame on Aβ(25-35)-caused oxidative stress, reactive astrogliosis, and impairment of spatial memory(.) The Aβ(25-35) (100 μM/μl) or vehicle was injected into the CA1 subfield of the hippocampus of the rat. The subcutaneous injection of prolame (400 μl, 50 nM) or sesame oil (400 μl) started 1 day before the Aβ(25-35) injection and was continued for another 29 days. The results showed a significant impairment of spatial memory evident 30 days after the Aβ(25-35) injection. The prolame treatment significantly reduced spatial-memory impairment and decreased lipid peroxidation, reactive oxygen species, and reactive gliosis. It also restored the eNOS and nNOS expression to normal levels. In conclusion the aminoestrogen prolame should be considered as an alternative in the treatment of Alzheimers disease.

The anticoagulant effect of prolame, N-(3-hydroxy-1,3,5(10) estratrien-17β-yl)-3-hydroxypropylamine, a novel amino-estrogen

The anticoagulant and estrogenic effects of prolame, N-(3-hydroxy-1,3,5(10)-estratrien-17 beta-yl)-3-hydroxypropylamine, are described. A single subcutaneous injection of prolame in male mice, ovariectomized mice, adult and infant male rats, produced dose-dependent increases of blood clotting time, which could be observed with the larger doses even after 4 days. In ovariectomized mice, prolame produced vaginal cornifications of shorter duration than those produced by estradiol-17 beta. The evidence suggests that, in contrast with currently used estrogens, prolame would not generate cardiovascular accidents if used for the treatment of prostatic carcinoma; it could also be exceptionally effective for the prevention of thrombosis.