Miscellaneous applications of ferrocene‐based peptides/amides

This article provides a critical review of the different applications of ferrocene‐based peptides/amides in biological as well as in non‐biological systems. Ferrocene‐based peptides/amides find many applications in different fields such as materials science, medicine, organic synthesis, bio‐organometallic and biological chemistry, asymmetric catalysis, nonlinear optics, in polymer science as redox active polymers and dendrimers, in molecular recognition as biosensors and in electrochemistry). Extensive research is being done on ferrocene‐based peptides/amides but we will highlight the various applications of ferrocene‐based peptides/amides for the period 2006–2010. The main factors that govern the potential biological and non‐biological applications are an electroactive core, a conjugated linker that can act as a chromophore and lower the oxidation potential of the ferrocene part, an amino acid or peptide derivative that can interact with other molecules via hydrogen bonding or any secondary bonding, and symmetric and asymmetric substitution on the ferrocene moiety. Copyright © 2011 John Wiley & Sons, Ltd.     

Numerical simulation of flow-induced fiber orientation using normalization of second moment

A normalization scheme for the numerical solution of the moment approximation equation in fiber suspension flows is presented. Here, normalization refers to rescaling the trace of the second moment tensor to unity at each time step. The equivalence between the normalization scheme and the quadratic closure model is analytically proved. The performance of the scheme is investigated in simple shear flow with respect to the quadratic and hybrid closures, and a stochastic Monte-Carlo simulator that provides exact solution. The proposed scheme is a computationally efficient alternative to the quadratic closure: it performs equally well and is more efficient regarding computational time.     

Synthesis of Some New Triphenylphosphanylidenes,Alkylphosphonates, and Heterocycles of Pyrazole Derivatives and Their Antimicrobial Activity

Abstract

The reaction of 5(4H)-pyrazolone with phosphorus ylides afforded new triphenylphosphanylidene alkanone derivatives. Moreover, its benzylidene derivative reacted with Wittig–Horner reagents to give the corresponding dialkoxyphosphoryl, alkyl phosphonate, and heterocyclic products. Treatment of pyrazole-4-carbaldehyde with Wittig–Horner reagents and trialkyl phosphites gave the respective alkyl phosphonate adducts. Mechanisms accounting for the formation of the new products are discussed. The biological activity of some of the newly synthesized compounds was also examined.     

Catalytic Chain-Transfer in Polymerization of Methyl Methacrylate. I. Chain-Length Dependence of Chain-Transfer Coefficient

Free-radical polymerization of methyl methacrylate has been conducted in the presence of a new catalytic chain-transfer agent at different temperatures. The new catalyst exhibits a strong chain transfer characteristic, and the chain-transfer coefficient varies from 2.8 × 10⁴ to 6.6 × 10⁴ and depends on chain length and temperature. The chain-transfer coefficients decrease with increasing chain length but reach a limiting value for chains more than 8 units in length. The activation energy for the chain transfer coefficient is -10.1 kJ/mol for this catalyst.     

Microwave Irradiation for Accelerating Synthesis of New Chiral Nanostructured Poly(amide-imide)s Having a Thiazole Pendant Group

Microwave irradiation was used to accelerate the polycondensation of a new thiazole-containing diamine with several chiral diacids. Polymerization reactions were carried out in molten tetrabutylammonium bromide as a green molten salt medium and triphenyl phosphite as the homogenizer. A series of new compounds were characterized by Fourier transform-infrared spectroscopy, nuclear magnetic resonance spectroscopy, and elemental analysis techniques. The polymeric samples showed high thermal stability with decomposition temperature being above 360°C; they were in a nanoscale size and were assembled uniformly and randomly in a sponge-like morphology.     

Dapson in Heterocyclic Chemistry,Part III: Synthesis,Antimicrobial, and Antitumor Activities of Some New Bisheterocyclic Compounds Containing Biologically Active Diphenylsulfone Moiety

The key intermediate diisothiocyanate 2 was allowed to react with 5-amino-3-methyl-pyrazole-4-carbonitrile 3, ethyl 5-amino-1-phenyl-pyrazole-4-carboxylate 6, 2-amino-tetrahydrobenzo[b]thiophene-3-car-bonitrile 9, ethyl-2-amino-tetra-hydrobenzo[b]thiophene-3-carboxylate 12, and/or 1,2,4-triazole 15 to give the corresponding biscompounds 4, 5, 7, 8, 10, 11, 13, 14, and 16, respectively. The structure of the synthesized compounds was elucidated by elemental analyses and spectral data. Some of the prepared compounds were tested for their antimicrobial and antitumor activities.     

A new scaled crossover parametric equation of state for water

In the present work, the asymmetric nature of water coexistence curve has been studied by investigating a new scaled crossover parametric equation of state. To do so, the concept of complete scaling [Fisher and Orkoulas, Phys Rev Lett 696, 85 (2000)] has been applied and the critical amplitudes near and far from the critical point have been derived. Also two mixing parameters $ a_{3} $ and $ b_{2} $ in the definition of scaling fields in terms of physical fields have been obtained for water. We have shown that mixing of the complete scaling theory and parametric equation of state can explain this nature quite carefully.     

A Convenient Synthesis of β-Amino Acid

We have reported the reductive cleavage of azlactones¹ and phenylhydrazones² of carbonyl compounds in the presence of a suitable catalyst. In this paper a general method involving a one step synthesis of β-amino acid^3,4, in good yield, through catalytic reduction of oximes of α-β-unsaturated acid is reported. This method involves the reaction of α, β-unsaturated acid with hydroxylamine hydrochloride in the presence of sodium acetate. Markovnikov's rule is followed in the synthesis of oximes of α, β-unsaturated acids.