Coumarins: antifungal effectiveness and future therapeutic scope

Molecular Diversity - The antifungals that are in current clinical practice have a high occurrence of a side effect and multidrug resistance (MDR). Researchers across the globe are trying to...     

Charge plate technique in recoil study: Evidence for collection of recoil charged species from solid targets on metal electrodes

The occurrence of charge on recoil⁵⁶Mn produced by the (n,γ) reaction in polycrystalline potassium permanganate has been examined using the ‘charge plate technique’. From considerations of capture gamma ray decay schemes and internal conversion it appears that, in a condensed medium, the recoil atom develops charge after losing much of its initial kinetic energy which allows collection on charged electrodes. Preliminary findings were presented at the International Symposium on Radiochemistry and Radiation Chemistry, RC-41 BARC, Bombay, Feb. 4–6 (1991).     

Simultaneous Approximation for Generalized Baskakov-Durrmeyer-Type Operators

The present paper deals with the study of a Durrmeyer-type integral modification of certain modified Baskakov operators. Here we study simultaneous approximation properties for these operators by using the iterative combinations. We obtain an asymptotic formula and an error estimation in terms of higher order modulus of continuity for these operators.      

On solving energy-dependent partitioned eigenvalue problem by genetic algorithm: The case of real symmetric Hamiltonian matrices

An energy-dependent partitioning scheme is explored for extracting a small number of eigenvalues of a real symmetric matrix with the help of genetic algorithm. The proposed method is tested with matrices of different sizes (30 × 30 to 1000 × 1000). Comparison is made with Löwdin’s strategy for solving the problem. The relative advantages and disadvantages of the GA-based method are analyzed     

Synthesis of a novel cis-proline-derived cyclic type VI beta-turn mimic via ring-closing metathesis

A cis-proline derived cyclic mimic of a type VI beta-turn is synthesized via a ring-closing metathesis reaction. The solution NMR conformational study indicates that the major conformer of the cyclic peptide adopts a type VIa beta-turn in CDCl(3) and a type VIb beta-turn in DMSO-d(6).     

Reverse turn induced pi-facial selectivity during polyaniline-supported cobalt(II) salen catalyzed aerobic epoxidation of N-cinnamoyl L-proline derived peptides

A novel chemo- and diastereoselective aerobic epoxidation of the N-cinnamoyl peptides catalyzed by polyaniline-supported cobalt(II) salen (PASCOS) is described. The N-cinnamoyl proline derived peptides 1 show a high pi-facial selectivity during these epoxidations. The origin of this diastereoselectivity in 1 has been attributed to (i) the propensity of the N-cinnamoyl proline amide to exist predominantly as trans rotamer in CDCl3, DMSO-d6, and CH3CN medium and (ii) existence of these peptides as organized structures (gamma- and beta-turns) due to the presence of intramolecular hydrogen bonds. An extensive solution NMR and MD simulation study on 1d and 1f indicates that the origin of the high pi-facial selectivity is due to the well-defined gamma- and beta-turns which result in the hindrance of one face of the cinnamoyl double bond in the transition state of the epoxidation reaction.     

Hot atom chemistry in oxyanion targets,part II1: Recoil behaviour of56Mn in permanganates

Fractional precipitation techniques have been utilized to separate the lower valent and parent forms of⁵⁶Mn in permanganate targets and an attempt is made to study a few aspects of chemical stabilization of recoil⁵⁶Mn in permanganates. Ammonium permanganate, recoil behaviour of which has not been studied previously, is chosen as one of the targets along with the potassium permanganate for initial retention and also for isothermal annealing.⁵⁶Mn initial retentions of about 12% and about 4% are obtained for potassium and ammonium permanganate, respectively, by activation from a Ra–Be neutron source. A usual trend for KMnO₄ and the reduction of recoil fragments by ammonium ions in NH₄MnO₄ are seen through the isothermal annealing study.     

Indexing scheme and similarity measures for macromolecular sequences

Nucleotide composition and distribution along a DNA sequence is known to play a vital role in the determination of gene functions. Protein coding regions, regulatory sequences, and other functional regions are determined generally by homology studies with comparable genes from other species or specific experimental verification. With the rapid and explosive increase in sequence information, new computational techniques for rapid determination of such information and comparative studies of different genes are becoming necessary which ideally should encompass not only DNA sequences but other macromolecular sequences as well.     

2-(Trimethylsilyl)ethyl chloroformate: A convenient reagent for protection of hydroxyl function

2-(Trimethylsilyl)ethyl chloroformate reacts with alcohols to give carbonates in high yield. n-Bu₄NF in THF(0.2M) solution for 10 min or ZnBr₂ or ZnCl₂ in CH₃NO₂ for 10 min regenerate the alcohol at 20°C.     

Some Novel Dinuclear phenylboronates of biologically potent β‐enaminoesters: Synthesis,Spectroscopic characterization,antimicrobial activity and their antiandrogenic effect

Organoboron derivatives of biologically potent β‐enamino esters of the type [Where R = CH₃(1a), C₂H₅ (1b), C₃H₇(1c) and C (CH₃)₃ (1d)] have been prepared by the reactions of β‐enamino esters and Phenyl boronic acid [PhB (OH)₂] in 1:2 molar ratio in refluxing tetrahydrofuran (THF). All these derivatives have been characterized by physico‐chemical properties, elemental analyses and molecular weight measurements. The structures of these compounds have been proposed on the basis of IR, ¹H, ¹³C, ¹¹B NMR spectral data and GC‐mass spectrometry. Phenyl boronic acid, β‐enamino esters and their respective phenylboronates derivatives have been screened for the antibmicrobial activities against pathogenic bacteria (B. subtilis and E. coli) and fungi (A. niger and P. peniculosum) to access their growth inhibiting potential. In addition to this, antiandrogenic effect of Ligand, L^aH₂ and its boron derivative (1a) has also been tested in male albino rats.