Propellanes—LII : The reaction of conjugated dienic propellanes with singlet oxygen

The reactions of propellanes containing one or two cyclohexadiene rings with singlet oxygen take the course of exclusive syn-attack with respect to a hetero-ring containing two CO groups. When only one or no CO group is found in the hetero-ring, both syn- and anti-attack occur. The former course is interpreted in terms of secondary orbital interactions which stabilize the transition state for syn-attack.     

Proliferation dynamics of germinative zone cells in the intact and excitotoxically lesioned postnatal rat brain

Background  

The forebrain subventricular zone (SVZ)-olfactory bulb pathway and hippocampal subgranular zone (SGZ) generate neurons into adulthood in the mammalian brain. Neurogenesis increases after injury to the adult brain, but few studies examine the effect of injury on neural and glial precursors in the postnatal brain. To characterize the spatio-temporal dynamics of cell proliferation in the germinative zones, this study utilized a model of postnatal damage induced by NMDA injection in the right sensorimotor cortex at postnatal day 9.     

A strategy for the build-up of transition-metal complexes containing tripodal [ArPOS2]2- and [ArPS3]2- ligands (Ar = 4-anisyl)

The investigation presents new synthetic methods for the generation of tripodal P/S ligands by reactions of metal alkoxides and carboxylates with the organoperthiophosphinic acid anhydride Lawesson's reagent. Four new transition-metal complexes containing various tripodal ligand sets were synthesised and characterised.     

A comparative study of first-derivative spectrophotometry and high-performance liquid chromatography applied to the determination of losartan potassium in tablets

Losartan, a highly effective blood pressure-lowering agent, has been widely used for the treatment of hypertension. A fast and reliable method for the determination of losartan was highly desirable to support formulation screening and quality control. A first-derivative UV spectroscopic method and HPLC were developed for the determination of losartan in the tablet dosage form. The first-derivative spectrum recorded between 220 and 320 nm and a zero-crossing technique for first-derivative measurement at 232.5 nm were selected. The selectivity and sensitivity of the method was in desirable range. In comparison with the direct UV method, first-derivative UV spectroscopy has a definite trough without any interference from UV absorbing-excipients. This method is also fast and economical in comparison with the more time-consuming HPLC method regularly used for formulation screening and quality control and can be used routinely by any laboratory possessing a spectrophotometer with a derivative accessory. The linear concentration ranges were 2-50 microg ml(-1), (D(1)=-0.0159C-0.0056, r=0.9994, n=6). Between-days CV of < or =2.9%, within-day CV of < or =2.1%, and analytical recovery close to 98.1% show the suitability of the method for determination in quality control.     

Oxidation of Aromatic Amines to Quinones by Iodic Acid under Microwave Irradiation in the Presence of Montmorillonite K10 and Silica Gel

Summary. A variety of aromatic amines are oxidized to their corresponding quinones in excellent yields by supported iodic acid under microwave irradiation and solvent free conditions.     

Surprising Formation of Chlorinated Butenolides from Dialkyl Acetylenedicarboxylates and Hexachloro­acetone in the Presence of Triphenyl Phosphite

Triphenyl phosphite reacts smoothly with dialkyl acetylenedicarboxylates and hexachloroacetone to produce alkyl 2‐(dichloromethylene)‐2,5‐dihydro‐5‐oxo‐4‐(trichloromethyl)furan‐3‐carboxylates in good yields.     

CuI-catalyzed Coupling Reactions of Aryl Iodides with Amides Using L-Proline and KF/Al2O3

An efficient experimentally simple and inexpensive catalyst system for the selective amidation of aryl iodides using 15 mol% of CuI as catalyst, 15 mol% of L-proline as ligand and KF/Al2O3 as a base in toluene is described.     

Kinetic modeling of aqueous phenol degradation by UV/H2O2 process

A dynamic kinetic model for the oxidation of phenol in water by an UV/H₂O₂ process is developed. The model is based on the elementary chemical and photochemical reactions, initiated by the photolysis of hydrogen peroxide into hydroxyl radicals. The model is validated by using experimental data obtained from the open literature for an actual UV/H₂O₂ process. Using those data and the developed kinetic model, kinetic rate constants for phenol intermediates, catechol and hydroquinone, are estimated. Moreover, the optimum initial hydrogen peroxide concentration is estimated by means of the validated model. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 40: 34–43, 2008     

Ellagic acid and human cancers: a systems pharmacology and docking study to identify principal hub genes and main mechanisms of action

Research on anticancer properties of natural compounds, as effective materials that are available while causing minimal side effects, is growing. Ellagic acid (EA) is a well-known polyphenolic compound, which has been found in both free and complex modes in several medicinal plants such as pomegranate, walnut, and berries. Although many articles have reported anticancer properties for this compound, its mechanism of action has not been fully elucidated. In this study, we used several online and offline bioinformatics tools and databases to identify the mechanism of action of EA on various types of human malignancies including bladder, blood, breast, cervical, colorectal, liver, pancreas, and prostate cancers. In this context, after identifying and extracting EA-affected human genes/proteins that have been reported in various references, we built the related gene networks and determined functional hub genes. In addition, docking was performed to recognize target proteins that react directly with EA and are in fact most affected by this compound. Our findings revealed that EA exerts its anticancer effects by influencing specific hub genes in various types of cancers. Moreover, different cellular signaling pathways are affected by this natural compound. Generally, it turned out that EA probably exerts most of its anticancer activities, through induction of apoptosis, as well as P53 and WNT signaling pathways, and also by affecting the expression of several hub genes such as CDKN1A, CDK4, CDK2, CDK6, TP53, JUN, CCNA2, MAPK14, CDK1, and CCNB1 and especially interactions with some related proteins including P53, CDK6, and MAPK14.