A facile and versatile protocol for the one-pot PhI(OAc)2 mediated divergent synthesis of quinazolines from 2-aminobenzylamine

In this present work iodobenzenediacetate (PIDA) has been found to be the key reagent in absence or presence of catalytic amount of molecular iodine (I₂)/zinc chloride (ZnCl₂) to construct quinazoline scaffold from 2-aminobenzylamine and a variety of easily available aldehydes, aryl and aliphatic amines, aliphatic and aryl alcohols and nitriles. This protocol provides mild and robust conditions along with great versatility to synthesize 2-substituted quinazolines from diverse starting materials in good to excellent yields. The developed protocol is also well applicable to reactants containing ease to oxidation prone functional groups.     

Cerium(IV) ammonium nitrate catalyzed synthesis of α-dehydro-β-amino esters

α-Dehydro-β-amino esters have been synthesized regioselectively from acetates of Baylis-Hillman adducts with amines in the presence of a catalytic amount of ceric ammonium nitrate (CAN) in good yield. The regioselectivity does not differ with respect to the polarity of the solvent.     

A p‐Hydroxyphenacyl–Benzothiazole–Chlorambucil Conjugate as a Real‐Time‐Monitoring Drug‐Delivery System Assisted by Excited‐State Intramolecular Proton Transfer

Among the well‐known phototriggers, the p‐hydroxyphenacyl (pHP) group has consistently enabled the very fast, efficient, and high‐conversion release of active molecules. Despite this unique behavior, the pHP group has been ignored as a delivery agent, particularly in the area of theranostics, because of two major limitations: Its excitation wavelength is below 400 nm, and it is nonfluorescent. We have overcome these limitations by incorporating a 2‐(2′‐hydroxyphenyl)benzothiazole (HBT) appendage capable of rapid excited‐state intramolecular proton transfer (ESIPT). The ESIPT effect also provided two unique advantages: It assisted the deprotonation of the pHP group for faster release, and it was accompanied by a distinct fluorescence color change upon photorelease. In vitro studies showed that the p‐hydroxyphenacyl–benzothiazole–chlorambucil conjugate presents excellent properties, such as real‐time monitoring, photoregulated drug delivery, and biocompatibility.     

Anomalous magnetic response of a quasi-periodic mesoscopic ring in presence of Rashba and Dresselhaus spin-orbit interactions

We investigate the properties of persistent charge current driven by magnetic flux in aquasi-periodic mesoscopic Fibonacci ring with Rashba and Dresselhaus spin-orbitinteractions. Within a tight-binding framework we work out individual state currentstogether with net current based on second-quantized approach. A significant enhancement ofcurrent is observed in presence of spin-orbit coupling and sometimes it becomes orders ofmagnitude higher compared to the spin-orbit interaction free Fibonacci ring. We alsoestablish a scaling relation of persistent current with ring size, associated with theFibonacci generation, from which one can directly estimate current for any arbitrary flux,even in presence of spin-orbit interaction, without doing numerical simulation. Thepresent analysis indeed gives a unique opportunity of determining persistent current andhas not been discussed so far.     

Nanocrystals,Nanorods and other Nanostructures of Nickel,Ruthenium, Rhodium and Iridium prepared by a Simple Solvothermal Procedure

The solvothermal decomposition of nickel acetate in n-octylamine medium at 250 °C gives rise to nickel nanostructures while in a hydrocarbon medium NiO nanostructures are obtained. It has been possible to obtain nickel nanorods of 12–15 nm diameter by this means. By carrying out the reaction at a slightly higher temperature, ultra-thin single-crystalline sheets of nickel are obtained. The nanorods and the thin sheets, with the FCC structure, are both ferromagnetic at room temperature, with the nanorods exhibiting high coercivities. It has been possible to obtain ruthenium, rhodium and iridium nanostructures by carrying out the decomposition of the respective metal acetylacetonates in a hydrocarbon (decalin or toluene) or an amine (n-octylamine or oleylamine) around 300 °C. Nanorod formation is favored by linear long-chain amines. The method described by us to prepare the nanostructures of nickel, ruthenium, rhodium and iridium is simple and straightforward compared to the literature procedures, the preparation of single-crystalline thin sheets of nickel by such a solution route being noteworthy. The nanostructures prepared in the amine media could be readily dispersed in hydrocarbon solvents. Dedicated to Professor Dr. Günther Schmid     

Multimodal approaches of the hydroalcoholic extract of Diospyros peregrina fruits in diabetic therapy

The matured fruits of Diospyros peregrina possess significant antidiabetic activity. The present investigation was undertaken to evaluate the target of action of the hydroalcoholic extract of D. peregrina fruit in diabetic pathophysiology. The extract was tested in vitro for inhibition of glucose absorption by α-amylase inhibition assay, glucose uptake study by isolated rat hemidiaphragm method and free radical scavenging activity by DPPH method. The extract exhibited significant α-amylase inhibition (IC?? 136.5 μg mL?1), peripheral glucose utilisation and radical scavenging (IC?? 167.5 μg mL?1) activity. From the results, it may be concluded that the hydroalcoholic extract of D. peregrina fruit can counteract diabetes by multiple mechanisms, namely inhibition of carbohydrate absorption, improving peripheral glucose utilisation and antioxidant defence.     

Solvent and Zn2+ Binding Effects on the Photo-physical Properties of (Dibenzoylmethanato)boron Difluoride

Absorption and emission spectroscopic studies of (dibenzoylmethanato)boron difluoride (1bf) in various polar and non-polar, protic and aprotic solvents are reported. The solvatochromic shifts of the spectral bands were examined in terms of solvent properties, including donor and acceptor numbers, followed by multilinear regression in which several solvent parameters were simultaneously analyzed. This π-conjugated positively charged system exhibits excellent solvatochromism. Variations in the electronic absorption spectral characteristics of 1bf were studied in solution in the presence of zinc perchlorate. Absorption spectral studies indicate stable complex formation between the zinc ion and 1bf in the ground state in aprotic dipolar benzonitrile rather than in protic polar solvent methanol. Zinc ion binding of 1bf was theoretically rationalized through frontier molecular orbital interaction.