Rhodium-Catalyzed C8-Alkenylation of Isoquinolones with Maleimides

An efficient Rh(III)-catalyzed C−H alkenylation of N-protected isoquinolone with maleimides is reported. The carbonyl group of isoquinolone acts as an inherent directing group. Various N-substituents in the maleimide, including alkyl, aryl, and even H and −OH, were well tolerated under the developed reaction condition. This protocol showed broad substrate scope, good selectivity, and excellent yields. Hammett plot is also drawn to check the effect of substituents on the reaction progress.     

Structural Properties of Hachimoji Nucleic Acids and Their Building Blocks: Comparison of Genetic Systems with Four,Six and Eight Alphabets

Expansion of the genetic alphabet is an ambitious goal. A recent breakthrough has led to the eight-base (hachimoji) genetics having canonical and unnatural bases. However, very little is known on the molecular-level features that facilitate the candidature of unnatural bases as genetic alphabets. Here we amalgamated DFT calculations and MD simulations to analyse the properties of the constituents of hachimoji DNA and RNA. DFT reveals the dominant syn conformation for isolated unnatural deoxyribonucleosides and at the 5′-end of oligonucleotides, although an anti/syn mixture is predicted at the nonterminal and 3′-terminal positions. However, isolated ribonucleotides prefer an anti/syn mixture, but mostly prefer anti conformation at the nonterminal positions. Further, the canonical base pairing combinations reveals significant strength, which may facilitate replication of hachimoji DNA. We also identify noncanonical base pairs that can better tolerate the substitution of unnatural pairs in RNA. Stacking strengths of 51 dimers reveals higher average stacking stabilization of dimers of hachimoji bases than canonical bases, which provides clues for choosing energetically stable sequences. A total of 14.4 μs MD simulations reveal the influence of solvent on the properties of hachimoji oligonucleotides and point to the likely fidelity of replication of hachimoji DNA. Our results pinpoint the features that explain the experimentally observed stability of hachimoji DNA.     

Thiacalixarene Appended Azo-based Supramolecular Systems: Self-assembly and Photo Tuning Reversible Liquid Crystalline Properties

Four new azo-based supramolecular materials containing thiacalixarene core substituted by variable alkoxy groups ( TFA₁ – TFA₄ ) have been designed and synthesized for the mesomorphic and photoswitching properties. The liquid crystalline behavior were accomplished by using DSC, POM, and XRD studies. All azo-based thiacalixarene based materials with short and higher chain length display columnar hexagonal mesophase with broad temperature range. The thermal behavior of all the materials was investigated by DSC and TGA study. The structural and conformational study of the lower rim functionalized materials was confirmed by using different techniques. These thiacalixarene moulded liquid crystalline compounds shows columnar self-assembly type behavior and higher thermal stability. The introduction of bi-substituted azo-ester network towards the lower rim of thiacalixarene core has impact on the electron delocalization and liquid crystalline properties. The photoswitching properties suggested cis and trans azo-isomerization under radiation of UV light and higher thermal back relaxation time. The mesogenic behaviour of compound TFA₂ and TFA₄ were demolished by the influence of cis and trans isomerization. The structure-property correlation is studied to understand the variation in mesogenic properties with the substitution of variable alkoxy side chain.     

Presence of pesticides in breast milk and infants’ formulae in Himachal Pradesh,India

This study documents the levels of pesticide residues in milk samples of mothers from Himachal Pradesh, India, and time trend comparison of pesticide load based on various studies conducted around the world. The regional difference in xenobiotic levels of breast milk varied with demographic characteristics of mothers and altitudinal variations. The single or multiple pesticides contamination of p,p′-DDE, p,p′-DDT and chlorpyrifos was revealed in 27.45% mothers’ milk samples. Among these p,p′-DDE was the major contaminant found in 26.79% samples followed by p,p′-DDT (1.31%) and chlorpyrifos (0.65%). However, residues of other 26 pesticides comprising organochlorines, organophosphorus and synthetic pyrethroids included in this study were below detectable limit (BDL). The determination of a low DDT/DDE ratio (0.050) indicated past exposure of mothers to DDT from the environment. The pesticide residues level in samples drawn from 14 branded infant formulae was BDL. The calculated infants’ daily intake (DI) of DDT was 0.0015 mg kg^?1 body weight per day compared with a decade-old study (0.021 mg kg^?1 body weight per day) suggesting a sharp decline in the residue levels of these pesticides in the Himalayan region. The trend comparison with past studies conducted around the world indicate a decline in the levels of organochlorine pesticide residues in mothers’ milk and further drop of DI in infants. However, such comparisons confer very limited utilisation of data generated on pesticide load in mothers’ milk and simultaneous infants’ DI due to lack of proper research protocol.     

Dielectric and electro-optical studies of a nickel-ferrite-nanoparticle- doped ferroelectric liquid crystal mixture

Effect of magnetic nanoparticles (nickel ferrite) doping on the dielectric and electro-optical properties of a ferroelectric liquid crystal mixture has been studied. In a doped ferroelectric liquid crystal mixture, dispersion of a small amount (0.25 wt.%) of nickel ferrite nanoparticles decreases the polarization and improves the response time compared to an undoped mixture. The significant changes in the polarization and response time are explained on the basis of dipole–dipole interaction and anchoring phenomena. Dielectric permittivity also increases with increasing the temperature of the SmC* phase and shows a reduction in dielectric loss in a doped sample. A Goldstone mode is clearly observed at ～200 and ～500 Hz in an undoped and a doped sample, respectively.     

Some Geometric Properties of Analytic Functions Involving a New Fractional Operator

In this paper, we introduce and study a new fractional operator and its implications in terms of the Ruscheweyh derivative operator, the Sălăgean operator and a certain fractional differintegral operator. Some geometric properties of the analytic functions involving this operator are derived. We also consider some applications and derive certain corollaries of our main results. Some useful consequences and relationship of certain results with known results are also pointed out.

     

Genetic Diversity in Chemically Diverse Accessions of Bacopa monnieri

JPC – Journal of Planar Chromatography – Modern TLC - Bacopa monnieri (L.) Pennell, commonly known as Brahmi, is an important medicinal plant of the Ayurvedic System of Medicine and is...     

Structures and energetics of complexation of metal ions with ammonia,water, and benzene: A computational study

Quantum chemical calculations have been performed at CCSD(T)/def2‐TZVP level to investigate the strength and nature of interactions of ammonia (NH₃), water (H₂O), and benzene (C₆H₆) with various metal ions and validated with the available experimental results. For all the considered metal ions, a preference for C₆H₆ is observed for dicationic ions whereas the monocationic ions prefer to bind with NH₃. Density Functional Theory–Symmetry Adapted Perturbation Theory (DFT‐SAPT) analysis has been employed at PBE0AC/def2‐TZVP level on these complexes (closed shell), to understand the various energy terms contributing to binding energy (BE). The DFT‐SAPT result shows that for the metal ion complexes with H₂O electrostatic component is the major contributor to the BE whereas, for C₆H₆ complexes polarization component is dominant, except in the case of alkali metal ion complexes. However, in case of NH₃ complexes, electrostatic component is dominant for s‐block metal ions, whereas, for the d and p‐block metal ion complexes both electrostatic and polarization components are important. The geometry (M⁺–N and M⁺–O distance for NH₃ and H₂O complexes respectively, and cation–π distance for C₆H₆ complexes) for the alkali and alkaline earth metal ion complexes increases down the group. Natural population analysis performed on NH₃, H₂O, and C₆H₆ complexes shows that the charge transfer to metal ions is higher in case of C₆H₆ complexes. © 2016 Wiley Periodicals, Inc.     

Ferrocenyl,Alkyl, and Aryl‐Pyrido[2,3‐d]Pyrimidines as Vasorelaxant of Smooth Muscle of Rat Aorta via cAMP Conservation Through Phosphodiesterase Inhibition

New pyrido[2,3‐d]pyrimidines 11 , 12 , 13 , and 21 have been synthesized. The vasorelaxant effect on smooth muscle isolated from rat aorta, via PDEs inhibition, of these compounds along with other pyrido[2,3‐d]pyrimidines 14 , 15 , 16 , 17 , 18 , 19 , 20 reported earlier by our group, has also been determined. These pyrido[2,3‐d]pyrimidines 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 were synthesized by the reaction of ferrocenyl‐ethynyl ketones ( 1 , 2 , 3 , 4 ) or α‐alkynyl ketones ( 5 , 6 , 7 , 8 , 9 , 10 ) with 6‐amino‐1,3‐dimethyluracil using [Ni(CN)₄]^?4 as an active catalytic species, formed in situ in a Ni(CN)₂/NaOH/H₂O/CO/KCN aqueous system. Evaluation of the vasorelaxant effect of compounds 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 demonstrated that all compounds relax the tissue in a concentration‐dependent manner. The structural changes do not alter the effectiveness; however, there are differences related to potency expressed as EC₅₀. Compounds 12 (7‐ferrocenyl‐1,3‐dimethyl‐5‐(m‐tolyl)‐pyrido[2,3‐d]pyrimidine) and 13 (7‐ferrocenyl‐1,3‐dipropyl‐5‐(4‐metoxyphenyl)‐pyrido[2,3‐d]pyrimidine) were the most potent compounds, even more than rolipram, reference drug; the EC₅₀ was 0.41 ± 0.02 μM and 0.81 ± 0.11 μM for 12 and 13 , correspondingly. The EC₅₀ of compounds 15 (7‐ferrocenyl‐1,3‐dimethyl‐5‐phenyl‐pyrido[2,3‐d]pyrimidine), 14 (7‐ferrocenyl‐5‐(3,5‐dimethoxyphenyl)‐1,3‐dimethylpyrido[2,3‐d]pyrimidine), and 19 (5‐n‐butyl‐7‐ethyl‐1,3‐dimethylpyrido[2,3‐d]pyrimidine) was similar to EC₅₀ of rolipram. Compounds 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 significantly induce concentration‐dependent vasorelaxation in endothelium‐intact aortic rings. In addition, the relaxation responses to each compound in either endothelium‐intact or endothelium denuded aortic rings were comparable, suggesting that removal of the functional endothelium has no significant influence on its intrinsic vasorelaxant activity. In vitro capability of conserving cyclic‐AMP or cyclic‐GMP (adenosine and guanosine 3′, 5′‐cyclic monophosphate) via PDE inhibition for compounds 12 , 13 , 14 , 15 and 19 was evaluated. Compounds 15 and 19 show the highest percent inhibition effect (94.83% and 83.98%, respectively) for the decomposition of c‐AMP. Docking studies showed that the compound 15 was selective for the inhibition of PDE‐4.