First synthesis of (±)-vertilecanin A

5-[(Hydroxy)(phenyl)methyl]pyridine-2-carboxylic acid ((±)-vertilecanin A) was prepared from nicotinic acid in four steps with an overall yield of 29%. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2389–2390, October     

A versatile approach for the preparation of end‐functional polymers and block copolymers by stable radical exchange reactions

A versatile strategy for the preparation of end‐functional polymers and block copolymers by radical exchange reactions is described. For this purpose, first polystyrene with 2,2,6,6‐tetramethylpiperidine‐1‐oxyl end group (PS‐TEMPO) is prepared by nitroxide‐mediated radical polymerization (NMRP). In the subsequent step, these polymers are heated to 130 °C in the presence of independently prepared TEMPO derivatives bearing hydroxyl, azide and carboxylic acid functionalities, and polymers such as poly(ethylene glycol) (TEMPO‐PEG) and poly(ε‐caprolactone) (TEMPO‐PCL). Due to the simultaneous radical generation and reversible termination of the polymer radical, TEMPO moiety on polystyrene is replaced to form the corresponding end‐functional polymers and block copolymers. The intermediates and final polymers are characterized by ¹H NMR, UV, IR, and GPC measurements. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 2387–2395     

A numerical study of the semi‐classical limit for three‐coupled long wave–short wave interaction equations

We study numerically the semi‐classical limit for three‐coupled long wave–short wave interaction equations. The Fourier–Galerkin semi‐discretization is proved to be spectrally convergent in an appropriate energy space. We propose a split‐step Fourier method in the semi‐classical regime with the discussion of the meshing strategy, which is necessary to obtain correct numerical solution. Plane wave solution with weak and strong initial phases, solitary wave solution and Gaussian solution are considered to investigate the semi‐classical limit.     

Flow around a cylinder surrounded by a permeable cylinder in shallow water

The change in flow characteristics downstream of a circular cylinder (inner cylinder) surrounded by an outer permeable cylinder was investigated in shallow water using particle image velocimetry technique. The diameter of the inner cylinder and the water height were kept constant during the experiments as d?=?50?mm and h _w ?=?25?mm, respectively. The depth-averaged free-stream velocity was also kept constant as U?=?170?mm/s which corresponded to a Reynolds number of Re_d?=?8,500 based on the inner cylinder diameter. In order to examine the effect of diameter and porosity of the outer cylinder on flow characteristics of the inner cylinder, five different outer cylinder diameters (D?=?60, 70, 80, 90 and 100?mm) and four different porosities (???=?0.4, 0.5, 0.6 and 0.7) were used. It was shown that both porosity and outer cylinder diameter had a substantial effect on the flow characteristics downstream of the circular cylinder. Turbulent statistics clearly demonstrated that in comparison with the bare cylinder (natural case), turbulent kinetic energy and Reynolds stresses decreased remarkably when an outer cylinder was placed around the inner cylinder. Thereby, the interaction of shear layers of the inner cylinder has been successfully prevented by the presence of outer cylinder. It was suggested by referring to the results that the outer cylinder having 1.6????D/d????2.0 and 0.4????D/d????0.6 should be preferred to have a better flow control in the near wake since the peak magnitude of turbulent kinetic energy was considerably low in comparison with the natural case and it was nearly constant for these mentioned porosities ??, and outer cylinder to inner cylinder diameter ratios D/d.     

Modular photoinduced grafting onto approach by ketene chemistry

A modular approach for the synthesis of graft copolymers by the combination of reversible addition–fragmentation chain‐transfer (RAFT) polymerization and photoinduced acylation processes is described. In the two‐step approach, first the copolymers of benzodioxinone containing monomer, namely, 4‐oxo‐2,2‐diphenyl‐4H‐benzo[d][1,3]dioxin‐7‐yl methacrylate (BDMA) and methyl methacrylate (MMA) in different feed ratios were prepared by RAFT polymerization. In the subsequent step, dichloromethane solutions of these copolymers (PMMA‐co‐PBDMA) were irradiated at λ = 300 nm in the presence of independently prepared hydroxyl functional polymers such as poly(ethylene glycol) (MeO‐PEG‐OH) and poly(?‐caprolactone) (PCL‐OH). Side‐chain esterification reaction between photochemically generated ketene groups and hydroxyl functionalities resulted in the formation graft copolymers. The intermediates and final graft copolymers were characterized by ¹H NMR, UV, IR, fluorescence, and GPC measurements. The success of the process was also confirmed by a model reaction using pyrene methanol. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 274–280     

Synthesis,characterization, and crystal structure of 6,7a-dichloro-3a-hydroxyoctahydro-1<Emphasis Type="Italic">H</Emphasis>-indene-2,5-diyl diacetates

The first syntheses and characterizations of 6,7a-dichloro-3a-hydroxyoctahydro-1H-indene-2,5-diyl diacetates were successfully obtained starting from indan-2-ol. Epoxidation of 2 was carried out using mCPBA in methylene chloride followed by acetylation using acetyl chloride to furnish the diacetates. The structures of all synthesized compounds were characterized by spectroscopic methods.     

NH2‐Functionalized Multi Walled Carbon Nanotubes Decorated with ZnO Nanoparticles and Graphene Quantum Dots for Sensitive Assay of Pimozide

In this study, a novel and sensitive electrochemical nanosensor for the determination of antipsychotic drug Pimozide (PZ) is proposed using NH₂ functionalized multi walled carbon nanotubes (NH₂fMWCNT) decorated with and ZnO nanoparticles (ZnONPs) co‐catalyzed by graphene quantum dots (GQDs). Prior to electrochemical analyses of PZ, the designed nanosensor was well characterized in terms of surface morphology by scanning electron microscopy (SEM) and SEM armed with EDX analysis. Electrochemical impedance spectroscopy (EIS) employed to investigate the electron transfer capability and cyclic voltammetry (CV) technique was used to successfully compare the redox response of PZ on the surface of modified and unmodified electrode. The designed nanosensor response was linear between 6.25×10^?11–1.20×10^?7 M concentration range of PZ with a limit of detection value as 1.02×10^?11 M. The influence of interfering agents was further studied to examine the selectivity of the designed sensor. A rapid screening of PZ as is required in pharmaceutical and biological samples underscores the paramount importance of nano based electrochemical sensor for its sensitive and selective detection.