Envirocats,as Novel Solid‐Supported Catalysts for Friedel‐Crafts Acylation

The Friedel‐Crafts acylation reactions of substituted benzenes with acid chloride or anhydrides proceeded smoothly in the presence of a catalytic amount of novel solid‐supported reagents such as EPZG, EPZ10, EPIC and EPZE. These catalysts are reusable and environmentally friendly.     

Multiutility sophorolipids as nanoparticle capping agents: synthesis of stable and water dispersible Co nanoparticles

Sophorolipids are a class of glycolipids that can be obtained from fatty acids by simply treating them with yeast cells (Candida bombicola, ATCC 22214) and glucose. In this letter, we demonstrate the application of sophorolipids obtained from oleic acid as a capping agent for Co nanoparticles. Upon capping the nanoparticle surface, the sugar moiety of these sophorolipids is exposed to the solvent environment, making the nanoparticles stable and water-redispersible.     

Extractive spectrophotometric determinations of some phenothiazine derivatives in pharmaceutical preparations

Two sensitive methods for the determination of phenothiazine derivatives based on the formation of coloured salts of these drugs formed with Brilliant Blue or Orange-II in the presence of 0.1 M HCl are described. The ion pair salts formed are quantitatively extracted into chloroform and the dried chloroform solutions analyzed using spectrophotometry.     

Synthetic methods,III: Sulfated zirconia catalyzed thioacetalization of carbonyl compounds

Summary Sulfated zirconia effectively catalyzes the reaction of carbonyl compounds with 1,2-ethanedithiol or thiophenol to afford the corresponding dithioacetals as useful organosulfur synthons. Isolation of pure products in high yields by simple filtration and evaporation is an important feature of this method.

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Synthetische Methoden, 3. Mitt.: Thioacetalisierung von Carbonylverbindungen mit ZrO₂SO ₄ ^2– (Kurze Mitt.)

Zusammenfassung ZrO₂/SO _2– ⁴ katalysiert die Reaktion von Carbonylverbindungen mit 1,2-Ethandiol oder Thiophenol zu den als Organoschwefelsynthonen wertvollen entrsprechenden Dithioacetalen. Ein wichtiges Merkmal der Methode ist die einfache Isolierung der Produkte in guten Ausbeuten durch Filtration und Entfernung des Lösungsmittels.

     

Chemoselective Protection of Hydroxyl Groups and Deprotection of Silyl Ethers

 Trimethylsilylation of alcohols and phenols is carried out using hexamethyldisilazane and LiClO₄ under microwave irradiation and neutral conditions. The deprotection of silyl ethers is carried out similarly using natural kaolinitic clay and a few drops of water.     

Thermal Behaviour and Adsorption Properties of Natural Stilbite

Crystals collected from the Ellora valley(Aurangabad, MS, India) of the Deccan traps of India have beencharacterized as a stilbite (St) by X-ray diffraction, IRspectroscopy and chemical analyses. The thermal behaviour was studiedusing TG and DTA techniques. The sample was exchanged at refluxtemperature with NH4Cl and NH4St was prepared. This was furthertransformed to the H-form of stilbite (HSt) by heating at 573 K for 12 h.The samples so prepared were used for adsorption studies. The comparativestudy of sorption of these samples shows an increase in the sorptioncapacity of HSt. The isosteric heat was also computed for these samples.     

Antidepressant activity of Ceratonia siliqua L. fruit extract, a source of polyphenols

A previous study from our laboratory has shown the facilitatory effect of Ceratonia siliqua L. (Fabaceae) on the dopaminergic function. This study investigates the involvement of monoamines in the antidepressant activity of the total polyphenol content of Ceratonia siliqua extract (CS) in mice using a tail suspension test (TST) and forced swim test (FST). The immobility time in the TST and FST were significantly reduced by CS (25 and 50 mg kg(-1), i.p.). The extract considerably attenuated the duration of immobility induced by prazosin (62.5 μg kg(-1), i.p., an α-adrenoceptor antagonist) and eticlopride (0.1 μg kg(-1), i.p., a classical D2-like dopamine receptor antagonist) in both TST and FST, whereas the extract could not modify the immobility in mice treated with p-chlorophenylalanine (100 mg kg(-1), i.p., ×3 days; an inhibitor of serotonin synthesis) and baclofen (10 mg kg(-1), i.p., GABAB agonist). This suggests that the antidepressant effect of CS is mediated by dopamine and noradrenaline.     

Effect of myricetin on deoxycorticosterone acetate (DOCA)-salt-hypertensive rats

Chronic administration of myricetin (100 and 300?mg?kg?1, p.o., for 4 weeks) isolated from Vitis vinifera (Vitaceae) ameliorated hypertension and oxidative stress induced by deoxycorticosterone acetate (DOCA)-salt in rats. Myricetin treatment reduced systolic blood pressure, vascular reactivity changes and reversed the DOCA-induced increase in heart rate. Urinary sodium excretion was significantly decreased in animals treated with myricetin compared to the DOCA group when measured by flame photometer. The cumulative concentration response curve of serotonin (5-HT) and angiotensin II (Ang II) were shifted towards the right in rats treated with myricetin using the isolated rat fundus strip and ascending colon, respectively. Increased levels of thiobarbituric acid reactive substances and decreased levels of superoxide dismutase, catalase and reduced glutathione in the heart tissue were observed in animals treated with DOCA, which were reversed by myricetin. Thus, myricetin shows antihypertensive and antioxidant properties in the DOCA model of hypertension.