OptDesign: extending optimizable k-dissimilarity selection to combinatorial library design

Optimizable k-dissimilarity (OptiSim) selection entails drawing a series of subsamples of size k from a population and choosing the "best" candidate from each such subsample for inclusion in the selection set. By varying the size of the subsample, one can control the balance between representativeness and diversity in the selection set obtained. In the original formulation, a uniform random sampling from among valid candidates was used to draw the subsamples from a single target population. Here we describe in detail two key modifications that serve to extend the OptiSim methodology to vector selection for interdependent variables, specifically as applied to the design of combinatorial sublibraries. The first modification involves pivoting between variables: subsamples are drawn from each reagent pool in turn, with the viability of each candidate being evaluated in isolation as well as in terms of the products it will produce from complementary reagents already selected. The filters applied may be static or dynamic in nature, with molecular weight and hydrophobicity being examples of the former and structural diversity with respect to reagents already selected being an example of the latter. The second key modification is adding the ability to bias the selection of candidate reagents for inclusion in the subsamples. Taken together, these modifications support the efficient generation of multiblock and other sparse matrix designs that are both representative and diverse, and for which "backfilling" of designs edited to remove undesirable reagents or products is straightforward. The method is intrinsically fast and efficient, since enumeration of the full combinatorial is not required- only those candidates actually considered for inclusion need be evaluated. Moreover, because the subsample selection step is separate from the diversity-based selection of the "best" candidate, incorporating such bias in favor of a competing criterion such as low price provides a "natural," nonparametric mechanism for generating designs that are likely to be "good" in a double-objective, Pareto sense.     

Multispectroscopic and theoretical studies on rapid,selective and sensitive visual sensing of cyanide ion in aqueous solution by receptors possessing varying HBD property

Research on Chemical Intermediates - Three new benzoquinone–imidazole ensembles possessing varying number (0, 1 and 2) of electron-withdrawing bromo substituents on the quinone ring have been...     

Lanthanum Trichloride Catalysed Protective Tetrahydropyranylation of Alcohols and Phenols

Lanthanum Trichloride is an effective catalyst for the protective tetrahydropyranylation of alcohols and phenols. The catalyst is recycled almost quantitatively.     

Low temperature magnetic properties of Cr0.25Co0.25Zn0.5Fe2O4 nano particles

Low temperature Mössbauer and AC susceptibility have been used to study relaxation phenomena in nano-sized particles of Cr_0.25Co_0.25Zn_0.5Fe₂O₄. From these studies, the energy density constant for this system has been estimated to be 4 x 10⁶ erg/cm³. Cation distribution has also been determined and the observed results are correlated to calculated relaxation times.     

Development and Validation of a Stability-Indicating LC Method for Determination of Bexarotene in Softgel Dosage Formulation

This study focuses on a novel liquid chromatographic approach that has been developed and approved for the quantitative determination of bexarotene (BXT), its potential impurities in drug substances and drug products. Chromatographic separation was developed on a Symmetry C₈ (150 × 4.6) mm 5-µm column with a mobile phase containing an isocratic mixture of acetonitrile:DI water:glacial acetic acid (650:350:7.5) v/v/v at a flow rate of 1.2 mL min^?1, and quantitation was carried out using ultraviolet detection at 262 nm for BXT and 290 nm for BHA with a column temperature of 35 °C. The resolution among butylated hydroxyanisole (BHA), BXT and its process-related impurity-A was found to be greater than 5. Regression analysis confers an R value (correlation coefficient) higher than 0.998 for BHA, BXT and impurity-A. The detection level for BXT impurities was found at a level below 0.03% (0.18 µg mL^?1). The inter- and intra-day precisions for BHA, BXT and impurities were evaluated and found to have a %RSD of less than 3.0.     

Molecular Cloning,Characterization, and Expression Analysis of Lignin Genes from Sugarcane Genotypes Varying in Lignin Content

Sugarcane (Saccharum spp.) is one of the highest biomass-producing plant and the best lignocellulosic feedstock for ethanol production. To achieve more efficient conversion of biomass to ethanol, a better understanding of the main factors affecting biomass recalcitrance is needed. Therefore, with this objective, here, we report a systematic study on lignin content, deposition, identification, and cloning of genes involved in lignin biosynthesis and their differential expression in five sugarcane clones, EC11003, EC11010, IK 76-91, IK 76-99, and Co 86032. Lignin content among the clones varied from 26.87 to 23.19 % with the highest in the clone EC11010 and the lowest in high sugar Co86032. Lignin deposition studied through phloroglucinol staining of the cell walls implied that the sclerenchyma cells of the energy canes (EC11010 and EC11003) have more lignin deposition followed by the Erianthus (IK 76-91 and IK 76-99) clones whereas Co86032 has the minimum amount of lignin deposition. We cloned partial coding regions of important genes of lignification COMT (650 bp), CCR (332 bp), and PAL (650 bp) from Erianthus, wild relative of sugarcane followed by the expression analysis through real-time PCR. Differential expression analysis showed high level of expression for the three genes in the energy cane EC11010.     

An Efficient N‐Arylation of Heterocycles with Aryl‐, Heteroaryl‐, and Vinylboronic Acids Catalyzed by Copper Fluorapatite

N‐Arylation of N‐containing heterocycles, such as pyrazoles, imidazoles, and benzimidazoles with aryl‐, heteroaryl‐, and vinylboronic acids was efficiently carried out by copper fluorapatite (CuFAP) catalyst in MeOH at room temperature under base‐free conditions. The N‐arylated heterocycles were isolated in good‐to‐excellent yields.     

An expedient approach for the synthesis of dispiropyrrolidine bisoxindoles, spiropyrrolidine oxindoles and spiroindane-1,3-diones through 1,3-dipolar cycloaddition reactions

A series of dispiropyrrolidine bisoxindoles were synthesized via a multicomponent 1,3-dipolar cycloaddition reaction of isatin, sarcosine and isatylidene malononitrile in refluxing methanol. Also a series of spiropyrrolidine oxindoles and spiroindane-1,3-diones were synthesized using 2-(1H-Indole-3-carbonyl)-3-phenyl-acrylonitrile and 2-(1,3-dioxo-indan-2-ylidene)-malononitrile as dipolarophiles, respectively.     

MoO2(acac)2-A Mild and Efficient Catalyst for the Deprotection of Acetals

Molybdenyl(VI) acetylacetonate is an effective catalyst for the deprotection of acetals into the corresponding aldehydes and ketones, in good yields.