Preparation and Characterization of Organic Nanoparticles of Oxadiazole Derivative in Aqueous Media

A novel  oxadiazole derivative, 2,5-disubstituted-1,3,4-oxadiazole (Z)-4-((1-(5-(4-hydroxyphenyl)-1,3,4-oxadiazol-2-yl)prop-1-en-2-yl)amino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (HOPA) was synthesized from reaction of (Z)-3-[(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)amino]but-2-enehydrazide, with 4-hydroxybenzaldehyde in the presence of iodine as catalyst .The structure of HOPA was characterized by using IR,1H-NMR and mass spectroscopy. Nanoparticles of the prepared compound HOPA have been fabricated in aqueous media using re-precipitation method. Characterizations of the organic nanoparticles (ONPs) have been performed by using UV-Vis spectrophotometry, and scanning electron microscope (SEM). The HOPA NPs were approximately monodisperse even without using capping agent or surfactant. The size of the nanoparticles were around 150-200 nm as indicated by SEM. The maximum of absorption spectrum of the dispersed nanoparticles is red shifted by 5 nm from the molecular absorption spectra of the HOPA in the solution, which indicate head to head alignment (J aggregate) of the molecules of HOPA during the aggregation. The well dispersed organic nanoparticles in aqueous media holds potential application in future to be used as a tag for biomedical imagining. Keywords: Nanoscience, Organic Nanoparticle, Reprecipitation, Oxdiazoles

Synthesis, Spectroscopic Studies and Keto-Enol Tautomerism of Novel 1,3,4-Thiadiazole Derivative Containing 3-Mercaptobutan-2-one and Quinazolin-4-one Moieties

In this study, a novel 1,3,4-thiadiazole derivative containing 3-mercaptobutan-2-one and quinazolin-4-one moieties (Compound 3) is synthesized by the coupling of 2-amino-1,3,4-thiadiazole-5-(3-mercaptobutan-2-one) (Compound 1) with 2-Phenyl-4H-3,1-benzoxazin-4-one (Compound 2) in one molecule moiety. Compound 3 is found to exist as two types of intra-molecular hydrogen bonding with keto-enol tautomerism characters, which is further confirmed using FTIR, 1H-NMR, 13C-NMR, mass spectrometer, and UV-Visible spectra. The 1H-NMR and UV-Visible spectra of Compound 3 are investigated in different solvents such as methanol, chloroform, and DMSO. Compound 3 exhibits keto-enol tautomeric forms in solvents with different percentage ratios depending on the solvent polarity. The 1H-NMR and UV-Visible spectral results show that Compound 3 favors the keto over the enol form in polar aprotic solvents such as DMSO and the enol over the keto form in non-polar solvents such as chloroform. The 13C-NMR spectrum gives two singles at δ 204.5 ppm, due to ketonic carbon, and δ 155.5 ppm, due to enolic carbon, confirming the keto-enol tautomerism of Compound 3. Furthermore, the molecular ion at m/z 43 and m/z 407 in the mass spectrum of Compound 3 and fragmentation mechanisms proposed reveal the existence of the keto and enol forms, respectively

Radiochemical, Computational, and Spectroscopic Evaluation of High-Denticity Desferrioxamine Derivatives DFO2 and DFO2p toward an Ideal Zirconium-89 Chelate Platform

Desferrioxamine (DFO) has long been considered the gold standard chelator for incorporating [89Zr]Zr4+ in radiopharmaceuticals for positron emission tomography (PET) imaging. To improve the stability of DFO with zirconium-89 and to expand its coordination sphere to enable binding of large therapeutic radiometals, we have synthesized the highest denticity DFO derivatives to date: dodecadentate DFO2 and DFO2p. In this study, we describe the synthesis and characterization of a novel DFO-based chelator, DFO2p, which is comprised of two DFO strands connected by an p-NO2-phenyl linker and therefore contains double the chelating moieties of DFO (potential coordination number up to 12 vs 6). The chelator DFO2p offers an optimized synthesis comprised of only a single reaction step and improves water solubility relative to DFO2, but the shorter linker reduces molecular flexibility. Both DFO2 and DFO2p, each with 6 potential hydroxamate ligands, are able to reach a more energetically favorable 8-coordinate environment for Zr(IV) than DFO. The zirconium(IV) coordination environment of these complexes were evaluated by a combination of density functional theory (DFT) calculations and synchrotron spectroscopy (extended X-ray absorption fine structure), which suggest the inner-coordination sphere of zirconium(IV) to be comprised of the outermost four hydroxamate ligands. These results also confirm a single Zr(IV) in each chelator, and the hydroxide ligands which complete the coordination sphere of Zr(IV)-DFO are absent from Zr(IV)-DFO2 and Zr(IV)-DFO2p. Radiochemical stability studies with zirconium-89 revealed the order of real-world stability to be DFO2 > DFO2p ≫ DFO. The zirconium-89 complexes of these new high-denticity chelators were found to be far more stable than DFO, and the decreased molecular flexibility of DFO2p, relative to DFO2, could explain its decreased stability, relative to DFO2

The role of the Hoxa10/HOXA10 gene in the etiology of endometriosis and its related infertility: a review

Endometriosis and its associated infertility have been the object of continuous research for over a century. To understand the molecular mechanisms underlying the disease, it has become necessary to determine the aspects of its etiology that are not explained by the retrograde menstruation theory. This could in turn elucidate how various clinical and surgical treatments might affect the evolution and remission of the disease.This review is focused on the most recent clinical and laboratory findings regarding the association of HOXA10 with endometriosis and infertility.The homebox (Hox/HOX) proteins are highly conserved transcription factors that determine segmental body identities in multiple species, including humans. Hoxa10/HOXA10 is directly involved in the embryogenesis of the uterus and embryo implantation via regulation of downstream genes. Cyclical endometrial expression of Hoxa10/HOXA10, with a peak of expression occurring during the window of implantation, is observed in the adult in response to estrogen and progesterone. Women with endometriosis do not demonstrate the expected mid-luteal rise of HOXA10 expression, which might partially explain the infertility observed in many of these patients. Recent studies also demonstrated HOXA10 expression in endometriotic foci outside the Mullerian tract.Multiple lines of evidence suggest that the actions of the homeobox A10 (Hoxa10/HOXA10) gene could account for some aspects of endometriosis.Huntington Med Reprod, BR-04501000 São Paulo, BrazilFac Med São Paulo, Dept Patol, São Paulo, BrazilHosp Clin São Paulo, Dept Ginecol, Fac Med São Paulo, São Paulo, BrazilYale Univ, Sch Med, Dept Obstet & Gynecol, Div Reprod Endocrinol & Infertil, New Haven, CT 06510 USAUniversidade Federal de São Paulo, Dept Ginecol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Ginecol, São Paulo, BrazilWeb of Scienc