Syntheses of mGluR5 PET radioligands through the radiofluorination of diaryliodonium tosylates

3-Fluoro-1-((thiazol-4-yl)ethynyl)benzenes constitute an important class of high-affinity metabotropic glutamate subtype 5 receptor (mGluR5) ligands, some of which have been labeled with fluorine-18 (t(1/2) = 109.7 min), to provide radioligands for molecular imaging of brain mGluR5 in living animal and human subjects with positron emission tomography (PET). Labeling in the 3-fluoro position of such ligands can be achieved through aromatic nucleophilic substitution of a halide leaving group with [(18)F]fluoride ion when a weakly activating m-nitrile group is present, but is generally very low yielding (<8%). Here we used a microfluidic reaction platform to show that greatly enhanced (up to 6-fold) radiochemical yields can be achieved from suitably synthesized diaryliodonium tosylate precursors. The presence of a m-nitrile or other activating group is not required. Similar conditions were adopted in a more conventional automated radiochemistry platform having a single-pot reactor, to produce mGluR5 radioligands with useful radioactivities for PET imaging.     

Effect of polycarboxylate type of super plasticizer on the hydration properties of composite cements

The work aims to study the effect of polycarboxylate type of super plasticizer on the hydration of composite cements. In this paper we have studied the hydration of 20 wt% fly ash (FA) blended Portland cement in the presence of 0.1 wt% super plasticizer (SP). Water consistency, setting times, non-evaporable water contents, compressive strength, water percolation, and air content measurements were carried out. In addition, X-ray diffraction studies were carried out to understand the hydration process. The results indicated the increase in compressive strength of the FA blended Portland cement in the presence of SP and with the increase of the hydration time.     

Photochemistry of 5-aminoquinoline in protic and aprotic solvents

Photophysical properties of 5-aminoquinoline (5AQ) have been investigated in various non-polar and polar (protic and aprotic) solvents using steady state and time resolved fluorescence. In aprotic solvents, the spectral maxima depend on the polarity. However, in protic solvents both the fluorescence intensity as well decay time show decrease depending on the hydrogen bonding ability of the solvent. The results suggest that photochemistry 5AQ is quite sensitive towards the polarity as well as protic character of the solvent.     

Fabrication of an Electrochemical Sensor Based on Multiwalled Carbon Nanotubes for Almotriptan

In the present work, the electrochemical behavior of an antimigraine drug, almotriptan malate (ALM), on a multiwalled carbon nanotube (MWCNT) film modified glassy carbon electrode under cyclic voltammetry was described for the first time. A significant enhancement in the oxidation peak current of ALM was noticed at MWCNT‐GCE. This property was exploited to develop a simple, sensitive and time‐saving differential pulse voltammetric method for the determination of ALM in bulk and pharmaceutical samples. A linear relationship was observed between concentration and peak current with a correlation coefficient of 0.9915 in the range of 0.25–37.5 µM ALM.     

Arbitrage and the tax code

We provide a detailed characterization of arbitrage-free asset prices in the presence of capital gains and income taxes. The distinguishing feature of our analysis is that we impose on the model two important features of the tax code: the limited use of capital losses and the inability to wash sell. We show that under remarkably mild conditions, the lack of pre-tax arbitrage implies the lack of post-tax arbitrage with the limited use of capital losses. The conditions are that the risk free interest rate be positive and that tax rates on interest income exceed capital gains tax rates. The result also holds when only a wash sale constraint is imposed and no investor holds a portfolio with a large capital loss. We allow investors to face different tax rates and have different bases for the calculation of capital gains taxes. The characterizations we provide have important implications for both asset pricing and portfolio choice. Our results imply that models that use arbitrage-free pre-tax models continue for derivative pricing and hedging are also arbitrage free in a world with taxes. Similarly, portfolio choice models with taxes typically specify pre-tax arbitrage free price processes and then analyze portfolio choice in the presence of taxes. In these models, it is unclear if portfolio recommendations are based on risk-return tradeoffs or on the arbitrage opportunities present in the model. Our results imply that if the above features of the tax code are modeled explicitly, then we can isolate the post-tax risk-return tradeoffs.     

Synthetic Approaches to Some Polymethine Asycyanine Colorants; Impact of Functional Additives & Chain Elongation on Visible Electronic Spectra

Twenty one new chromophoric chain β‐substituted polymethine asycyanine (CCBSPA) colorants have been synthesised by catalytic condensation of (i) 4‐dimethylaminophenylbutadientylphenyl ketone; (ii) 4‐dimethylbutadienyl‐4‐nitrophenyl ketone; and (iii) 4‐dimethylaminophenylbutadienyl‐4‐methyl‐phenyl ketone with 2‐methyl quinoline methiodide and 2‐methyl‐6‐substituted quinoline methiodides using piperidine as catalyst & ethanolic DMF as solvent. These colorants were synthesized with the object to study the impact of various functional groups and chain lengthening on visible electronic spectra. All the colorants showed increase in electronic spectra whether electron withdrawing or donating. These colorants also absorb at higher wavelengths when compared to the previously reported butadienylene chain asycyanino‐colorants.     

Catalytic asymmetric dihydroxylation of olefins with recyclable osmate-exchanged chloroapatite catalyst

An osmate-exchanged chloroapatite (CAP-OsO₄) catalyst was prepared by an ion-exchange technique. CAP-OsO₄ efficiently catalyses asymmetric dihydroxylation of olefins including α,β-unsaturated esters and amides to afford the corresponding diols in high yields and enantioselectivities. The catalyst was reused for several cycles with consistent activity.     

β-Diketonates of Cyclopalladated Arylazonaphthalenes: Synthesis, Characterization and Redox Activity

The synthesis of monomeric mixed species of the type [PdLK] (L = cyclopalladated arylazonaphthalenes) have been achieved by splitting the halogeno-bridge in [Pd₂L₂Cl₂] by β-diketones (HK). The compounds have been characterized on the basis of spectral (IR, UV–VIS, FAB mass, ¹H and ¹³C{¹H}NMR) and elemental analysis data. Some of the [PdLK] cyclometallates occur as isomeric mixtures whose composition have been established by ¹H-NMR data. Electron transfer properties of the cyclopalladates in DMF have been thoroughly examined using cyclic voltammetry.     

Cinnamoyl shikonin

The title compound, 1-(5,8-di­hydro-1,4-di­hydroxy-5,8-dioxo-2-naphthyl)-4-methyl­pent-3-en-1-yl cinnamate, C₂₅H₂₂O₆, crystallizes in space group P2₁. The phenyl ring of the cinnamate is anti to the carbonyl group of the same moiety [C—C—C—C = −175.6 (2)°] and is nearly parallel to the naphthyl ring system. Two six-membered rings formed by intramolecular hydrogen bonds, with O—H⃛O distances of 2.587 (2) and 2.589 (2) Å, occur on either side of the fused ring system, creating a tetracyclic pyrene-shaped system. The phenyl ring forms an intermolecular stack with the benzo­quinone ring, as a result of aromatic π–π interactions.