Retracted: Effective and Green One‐Pot Multicomponent Synthesis of Novel Derivatives of 4H‐Pyrans in the Presence of Hexamethylenetetramine as Catalyst in Water Medium

Hexamethylenetetramine (HMTA) catalyzes synthesis of new polyfunctionalized 4H‐pyrans by reaction of aromatic aldehyde, malononitrile, and β‐keto esters via one‐pot three‐component procedure in water medium. Addition of reactants was performed by two methods led to achieve similar results. Using HMTA in catalytic amount not only represents the economic face of the reaction, but also due to the use of water, a green and safe reaction condition is organized. Thus, the current strategy provides the benefits of high productivity, convenient operation, and environmental friendliness. Structure of all products was proved by elemental analysis, IR, ¹H‐NMR, and ¹³C‐NMR spectroscopy.     

The role of the Rashba coupling in spin-current of monolayer gapped graphene

In the current work, based on a semiclassical Boltzmann approach, we have investigatedthe influence of the Rashba spin-orbit coupling on spin-current of a single layer gappedgraphene. It was shown that the Rashba coupling plays a considerable role in thegeneration of the spin-current of vertical spins in mono-layer graphene. The behavior ofthe spin-current is determined by the density of impurities. It was also shown that thespin-current of the system could increase by increasing the Rashba coupling strength andband-gap of the graphene and the sign of the spin-current could be controlled by thedirection of the current-driving electric field.     

Approximate solutions of Dirac equation for Tietz and general Manning-Rosen potentials using SUSYQM

In this paper, we consider the relativistic Dirac equation with Tietz and general Manning-Rosen potential. By using appropriate approximation, we obtained the approximate analytical solutions of the Dirac equation for the combined potential via the supersymmetric quantum mechanics (SUSYQM). Within the framework of spin and pseudospin symmetry limits, we obtained the relativistic energy eigenvalus and the corresponding components of the wave functions for Tietz and Manning-Rosen potential using the SUSYQM. We have also reported some numerical results and figures to show the effect of the tensor interactions.     

Structure of \mathrm {Gal}(\mathbb {k}_2^{(2)}/\mathbb {k}) for some fields \mathbb {k}=\mathbb {Q}(\sqrt{2p_1p_2},i) with \mathbf {C}l_2(\mathbb {k})\simeq (2, 2, 2)

Let \(p_1 \equiv p_2 \equiv 5\pmod 8\) be different primes. Put \(i=\sqrt{-1}\) and \(d=2p_1p_2\) , then the bicyclic biquadratic field \(\mathbb {k}=\mathbb {Q}(\sqrt{d},i)\) has an elementary abelian 2-class group of rank \(3\) . In this paper we determine the nilpotency class, the coclass, the generators and the structure of the non-abelian Galois group \(\mathrm {Gal}(\mathbb {k}_2^{(2)}/\mathbb {k})\) of the second Hilbert 2-class field \(\mathbb {k}_2^{(2)}\) of \(\mathbb {k}\) . We study the capitulation problem of the 2-classes of \(\mathbb {k}\) in its seven unramified quadratic extensions \(\mathbb {K}_i\) and in its seven unramified bicyclic biquadratic extensions \(\mathbb {L}_i\) .     

Versatile and Large-Scale Synthesis of Functional Dithiocarbamates in Water

Structural diversity is possible in direct access to functional dithiocarbamates based on a highly efficient and simple one-pot reaction of CS₂, amines, and alkyl halides in nearly quantitative yields in water.     

Dynamics of PEGylated–Dextran–Spermine Nanoparticles for Gene Delivery to Leukemic Cells

Leukemic cells are hard-to-transfect cell lines. Many transfection reagents which can provide high gene transfer efficiency in common adherent cell lines are not effective to transfect established blood cell lines or primary leukemic cells. This study aims to examine a new class of cationic polymer non-viral vector, PEGylated–dextran–spermine (PEG-D-SPM), to determine its ability to transfect the leukemic cells. Here, the optimal conditions of the complex preparation (PEG-D-SPM/plasmid DNA (pDNA)) were examined. Different weight-mixing (w/w) ratios of PEG-D-SPM/pDNA complex were prepared to obtain an ideal mixing ratio to protect encapsulated pDNA from DNase degradation and to determine the optimal transfection efficiency of the complex. Strong complexation between polymer and pDNA in agarose gel electrophoresis and protection of pDNA from DNase were detected at ratios from 25 to 15. Highest gene expression was detected at w/w ratio of 18 in HL60 and K562 cells. However, gene expression from both leukemic cell lines was lower than the control MCF-7 cells. The cytotoxicity of PEG-D-SPM/pDNA complex at the most optimal mixing ratios was tested in HL60 and K562 cells using MTS assay and the results showed that the PEG-D-SPM/pDNA complex had no cytotoxic effect on these cell lines. Spherical shape and nano-nature of PEG-D-SPM/pDNA complex at ratio 18 was observed using transmission electron microscopy. As PEG-D-SPM showed modest transfection efficiency in the leukemic cell lines, we conclude that further work is needed to improve the delivery efficiency of the PEG-D-SPM.     

Heteroaromatization with Sulfonamido Phenyl Ethanone,Part I: Synthesis of Novel Pyrrolo[2,3-D]Pyrimidine and Pyrrolo[3,2-E][1,2,4]Triazolo[1,5-C]Pyrimidine Derivatives Containing Dimethylsulfonamide Moiety

4-(5-Amino-4-cyano-1-p-tolyl-1H-pyrrol-3-yl)-N,N-dimethyl-benzenesulfonamide (4) was prepared and converted to several pyrrolo[2,3-d]pyrimidin-5-yl)-N,N-dimethyl-benzenesulfonamide derivatives (5,7,9, and 13). Cyclocondensation of 13 with different electrophilic carbon reagents afforded several 4-(N,N-dimethylaminosulfonylphenyl)]pyrrolo[3,2-e][1,2,4]triazolo[1,5-c]-pyrimidine derivatives (14–17,19, and 20); IR, ¹HNMR, and mass spectra of the newly synthesized compounds were recorded. Most of the obtained compounds were screened against Gram-positive and Gram-negative bacteria and fungi, for which some of these derivatives gave promising results.     

Synthesis of New 1,4-Dihydropyridine Derivatives Containing Thiazolyl Substituents

A series of 4-[2-methyl (or aryl) thiazole-4-yl]-2,6-dimethyl-3,5-diacetyl (or dibenzoyl) 1,4-dihydropyridines were synthesized using a modified Hantzsch reaction involving the condensation of the corresponding aldehyde with acetyl acetone or benzoyl acetone. The preparation of the corresponding aldehydes (2-methylthiazole-4-carboxaldehyde and some 2-arylthiazole-4-carboxaldehydes) was achieved by a simplified protocol of the published synthesis.     

Trimethylsilyl Protection of Alcohols Over Phosphorus Pentoxide Supported on Silica Gel

Abstract

An eco-friendly and mild protocol for trimethylsilyl protection of alcohols over phosphorus pentoxide supported on silica gel using hexamethyldisilazane has been described. Solvent-free and ambient reaction conditions, easy workup, short reaction times, excellent yields, and reusability of the catalyst are the noticeable features of this methodology.

GRAPHICAL ABSTRACT