Showing papers by "Anju Chadha published in 2016"
TL;DR: C. parapsilosis can now be considered a 'reagent' for the organic transformations discussed here, and design of new reactions which can be considered for large scale operations are provided.
17 citations
TL;DR: In this article, the synthesis, single crystal structure and complete spectral characterization of two heteroaryl chalcones are presented, namely (i) (E)-3-(benzo[b]thiophen-3-yl)-1-(2-hydroxyphenyl)prop-2-en-1-one (C17H12O2S) and (ii)(E)-1-aminophenyl)-3-polyphenyl)-4-carbaldehyde based novel hetero-aligno-chalcone.
Abstract: The present study highlights the synthesis, single crystal structure and complete spectral characterization of two heteroaryl chalcones, namely (i) (E)-3-(benzo[b]thiophen-3-yl)-1-(2-hydroxyphenyl)prop-2-en-1-one (C17H12O2S) and (ii) (E)-1-(2-aminophenyl)-3-(benzo[b]thio phen-3-yl)prop-2-en-1-one (C17H13NOS). In both of these compounds, the molecules show weak intermolecular C–H···O interactions utilizing the keto group in addition to hydrogen bonding including hydroxyl and amino groups. In the case of compound (ii) water molecules are trapped in voids of the crystal lattice. π–π stacking interactions between phenyl and benzothiazole rings are observed in the crystal packing. In addition to crystallographic data, both the structures are also described for the first time with 1H NMR, H–H Cosy, 13C NMR, DEPT-135, HR-MS, TGA-DTG, DSC, IR and UV spectral data. The synthesis, single crystal structure and complete spectral characterization of benzo[b]thiophene-3-carbaldehyde based novel heteroaryl chalcones.
11 citations
TL;DR: The membrane and the pore walls develop a net negative charge in alcohol medium which facilitate the transport of neutral nanoparticles while impeding both the positively and negatively charged particles.
10 citations
TL;DR: The cell free extracts of Candida parapsilosis ATCC 7330 are more efficient than the whole resting cells of the yeast in the synthesis of directly usable gold nanoparticles as revealed by this systematic study.
Abstract: The cell free extracts of Candida parapsilosis ATCC 7330 are more efficient than the whole resting cells of the yeast in the synthesis of directly usable gold nanoparticles as revealed by this systematic study. Cell free extracts yielded gold nanoparticles of hydrodynamic diameter (50–200 nm). In this study, the total protein concentration influences the nanofabrication and not only the reductase enzymes as originally thought. Powder X-ray diffraction studies confirm the crystalline nature of the gold nanoparticles. Fourier Transform Infra Red spectroscopy and thermal gravimetric analysis suggests that the biosynthesized gold nanoparticles are capped by peptides/proteins. Dispersion experiments indicate a stable dispersion of gold nanoparticles in pH 12 solutions which is also confirmed by electron microscopic analysis and validated using a surface plasmon resonance assay. The effectiveness of the dispersed nanoparticles for the reduction of 4-nitrophenol using sodium borohydride as a reductant further confirms the formation of functional gold nanoparticles. It is also reported that gold nanoparticles with mean particle diameter of 27 nm are biosynthesized inside the whole cell by transmission electron microscopy analysis. With optimized reaction conditions, maximum gold bioaccumulation with the 24 h culture age of the yeast with cellular uptake of ~1010 gold atoms at the single cell level is achieved but it is not easy to extract the gold nanoparticles from the whole resting cells.
8 citations
TL;DR: In this paper, a bis-chalcone, (2E,2′E)-3,3′-(1,4-phenylene)bis(1-(2-aminophenyl)prop-2en-1-one) is synthesized through a base catalyzed Claisen-Schmidt condensation reaction of terephthalaldehyde with 2-aminoacetophenone.
Abstract: A novel bis-chalcone, (2E,2′E)-3,3′-(1,4-phenylene)bis(1-(2-aminophenyl)prop-2-en-1-one) is synthesized through a base catalyzed Claisen-Schmidt condensation reaction of terephthalaldehyde with 2-aminoacetophenone. Its structure (sp. gr. P
$$\bar 1$$
, Z = 2) is determined from single crystal X-ray diffraction data. There are two independent centrosymmetric molecules with no significant differences in bond lengths and angles between them. The NMR, IR, HRMS, and UV spectral data of the prepared bis-chalcone are presented.
6 citations
TL;DR: In this paper, the authors describe a method to distinguish the normal modes from the spurious modes for a cantilever, based on the actuation signal provided and laser beam size.
Abstract: Cantilevers immersed in liquid experience viscous damping and hydrodynamic loading. We report on the use of such cantilevers, operating in the dynamic mode with, (i) frequency sweeping and (ii) phase locked loop methods. The solution to reliability issues such as random drift in the resonant peak values, and interference of spurious modes in the resonance frequency spectrum, are explained based on the actuation signal provided and laser spot size. The laser beam spot size and its position on the cantilever were found to have an important role, on the output signal and resonance frequency. We describe a method to distinguish the normal modes from the spurious modes for a cantilever. Uncertainties in the measurements define the lower limit of mass detection (m min). The minimum detection limits of the two measurement methods are investigated by measuring salt adsorption from phosphate buffer solution, as an example, a mass of 14 pg was measured using the 14th transverse mode of a m × 100 μm × 1 μm silicon cantilever. The optimized measurement was used to study the interaction between antibody and antigen.
4 citations
TL;DR: A novel fluorescence method was developed using 1-(6-methoxynaphthalen-2-yl)ethanol to track the site of biotransformation within the cells and showed that the reaction occurs spontaneously and the products get released out of the cells in less time.
Abstract: Confocal microscopic studies with the resting cells of yeast, Candida parapsilosis ATCC 7330, a reportedly versatile biocatalyst for redox enzyme mediated preparation of optically pure secondary alcohols in high optical purities [enantiomeric excess (ee) up to >99%] and yields, revealed that the yeast cells had large vacuoles under the experimental conditions studied where the redox reaction takes place. A novel fluorescence method was developed using 1-(6-methoxynaphthalen-2-yl)ethanol to track the site of biotransformation within the cells. This alcohol, itself non-fluorescent, gets oxidized to produce a fluorescent ketone, 1-(6-methoxynaphthalen-2-yl)ethanone. Kinetic studies showed that the reaction occurs spontaneously and the products get released out of the cells in less time [5 mins]. The biotransformation was validated using HPLC.
2 citations
TL;DR: Enantiopure hydroxy ketones (II), (IV), (VI) are prepared by enzymatic reduction of the corresponding diketones (I), (III), (V) with high enantiomeric excesses and in good yields.
Abstract: Enantiopure hydroxy ketones (II), (IV), (VI) are prepared by enzymatic reduction of the corresponding diketones (I), (III), (V) with high enantiomeric excesses and in good yields.
TL;DR: In this paper, an asymmetric reduction of aliphatic nitro ketones was carried out in water with ethanol as cosolvent and glucose as cosubstrate using the whole cells of Candida parapsilosis ATCC 7330 in much lesser time (4 h).
Abstract: Enantiomerically pure β- and γ-nitro alcohols were prepared from their respective nitro ketones by asymmetric reduction mediated by the biocatalyst, Candida parapsilosis ATCC 7330 under optimized reaction conditions (ee up to >99%; yields up to 76%). This biocatalyst exhibits high chemoselectivity and reduces the keto group in preference to nitro group along with good enantioselectivity to produce enantiomerically enriched nitro alkanols. The asymmetric reduction of aliphatic nitro ketones was carried out in water with ethanol as cosolvent and glucose as cosubstrate using the whole cells of Candida parapsilosis ATCC 7330 in much lesser time (4 h). For the first time, the biocatalytic asymmetric reduction of the following ketones is reported here: 1-nitro-butan-2-one, 1-nitro-pentan-2-one, 3-methyl-1-nitro-butan-2-one and 1-cyclohexyl-2-nitroethanone to produce (R)-alcohols [ee up to 79%, yield up to 74%] and 1-nitro-hexan-2-one and 1-nitro-heptan-2-one to produce (S)-alcohols [ee up to 81%, yield up to 76%].