Enantioselective Synthesis of Thiazolopyran Derivatives via a Direct Vinylogous Michael-oxa-Michael Sequence.

An efficient diastereo- and enantioselective direct vinylogous Michael-oxa-Michael sequence between 5-alkenyl thiazolones and isopropylidene oxindoles has been developed. The reaction is catalyzed by a bifunctional squaramide catalyst that allows to access a wide range of densely substituted thiazolopyran derivatives containing a quaternary stereocenter. This protocol is flexible toward different sterically and electronically tuned substrates and is amenable to gram-scale synthesis and several synthetic transformations.

Organocatalytic Asymmetric Direct Vinylogous Michael Initiated Ring Closure Reaction of 4-Nitroisoxazole Derivatives to 3-Isopropylidene Oxindoles.

Herein, we present the first ever use of 3-isopropylidene oxindoles as electrophiles in vinylogous Michael initiated ring closure reaction (MIRC). Among the various alkylidene oxindoles used in enantioselective spirocyclization reactions, isopropylidene oxindoles are the least explored to date. The competing reactivity of isopropylidene oxindoles (electrophilicity vs nucleophilicity) in the presence of a chiral organocatalyst is controlled by the logical selection of a more reactive nucleophile. The methodology produces a library of densely substituted highly enantioenriched spirocyclopropyl oxindoles with excellent yield and stereoselectivities. Moreover, the first enantioselective synthesis of HIV-1 NNRT inhibitor indicates the importance of our synthesized spiro-cyclopropyl oxindole core.

Kinetic Resolution of Electron-Deficient Bromohydrins via Copper(II)-Catalyzed C-C Bond Cleavage.

Herein, we report a nonenzymatic kinetic resolution (KR) of α,ß-unsaturated ketone-derived bromohydrins (up to s = 211) with N-bromosuccinimide (NBS) in the presence of a chiral Cu(II)-Box catalyst via the C-C bond cleavage of the fast reacting enantiomer. A one-pot synthesis-KR approach of the same has also been realized with excellent enantioselectivities (up to 99% ee). Both protocols are found to be effective for a variety of substrates, leading to enantioenriched bromohydrins. The synthetic utility of this process has been demonstrated by exploring a new strategy to convert the resolved enantiomer to an optically active epoxide.

Label free optical biosensor for insulin using naturally existing chromene mimic synthesized receptors: A greener approach.

We currently reporting a simple and first label free optical insulin biosensor using a novel cum naturally existing Chromene mimic receptors via one pot greener methodology. Among synthesized 4H- Chromene derivatives, 2-amino-5,7-dihydroxy-4-(4-nitrophenyl)-4H-chromene-3-carbonitrile (Compound 1c) is showed a very good colorimetric response for insulin within the linear range of 20 fM -500 pM along with theoretically measured LOD of 15.38 fM based on the increment in absorbance. Meanwhile 2-amino-5, 7-dihydroxy-4-(pyren-2-yl)-4H-chromene-3-carbonitrile (Compound 1a) is depicted an excellent quenching in fluorescence response for insulin with LOD of 7.07 fM and along with wide working range from 10 fM -600 pM. The developed biosensor is tested for the detection of insulin in human blood serum using direct as well as standard addition method and the recovery results are showed a very good agreement with standard clinical chemiluminescent assay method. Hence, this developed biosensor is more reliable for clinical detection of Insulin and so a good analytical method for Diabetes diagnosis within a short period of time.

Asymmetric Synthesis of Spiro-3,3'-cyclopropyl Oxindoles via Vinylogous Michael Initiated Ring Closure Reaction.

A novel organocatalytic cascade approach for the synthesis of spiro-cyclopropyl oxindole derivatives has been developed. The methodology is based on asymmetric vinylogous Michael addition of 4-nitroisoxazole derivatives to N-Boc isatylidene malonates followed by intramolecular alkylation. Its remarkable stereocontrol, wide substrate scope, and scalability highlight this new developed strategy. Moreover, this work represents the first example of vinylogous Michael initiated ring closure (MIRC) reaction for the synthesis of chiral 3,3'-cyclopropyl oxindole.

Colorimetric detection and bio-magnification of bisphenol A in fish organs and water sources using 3',6'-bis(diethylamino)-2- ((3,4,5trimethyl benzylidene) amino) spiro [isoindoline -1,9'-xanthen ]-3-one (BTSIXO)-Fe3+ ion conjugate.

Current study is focusing mainly on the development of simple, novel, and cost-effective optical sensor to detect and quantify Bisphenol A (BPA) contamination. We designed a very selective and sensitive colorimetric sensor using synthesized 3', 6'- bis(diethylamino) -2- ((3,4,5 trimethyl benzylidene) amino)spiro [isoindoline-1,9'-xanthen] -3-one (BTSIXO) conjugated with Fe3+-ions via very simple eco- friendly synthetic protocol. The sensor has an excellent wide detection range for BPA from 0.1 to 150 ppm with LODs of 0.02 ppm. Finally, the applicability of the sensor was demonstrated in fish samples especially in the organs of Oreochromis mossambicus fingerlings and contaminated industrial water samples. The sensor was also applied for the quantification of BPA present drinking water stored in the plastic bottles. The developed sensor has shown a good agreement and accuracy when compared with ESI-Mass techniques.

Dichloromethane Degradation Pathway from Unsequenced Hyphomicrobium sp. MC8b Rapidly Explored by Pan-Proteomics.

Several bacteria are able to degrade the major industrial solvent dichloromethane (DCM) by using the conserved dehalogenase DcmA, the only system for DCM degradation characterised at the sequence level so far. Using differential proteomics, we rapidly identified key determinants of DCM degradation for Hyphomicrobium sp. MC8b, an unsequenced facultative methylotrophic DCM-degrading strain. For this, we designed a pan-proteomics database comprising the annotated genome sequences of 13 distinct Hyphomicrobium strains. Compared to growth with methanol, growth with DCM induces drastic changes in the proteome of strain MC8b. Dichloromethane dehalogenase DcmA was detected by differential pan-proteomics, but only with poor sequence coverage, suggesting atypical characteristics of the DCM dehalogenation system in this strain. More peptides were assigned to DcmA by error-tolerant search, warranting subsequent sequencing of the genome of strain MC8b, which revealed a highly divergent set of dcm genes in this strain. This suggests that the dcm enzymatic system is less strongly conserved than previously believed, and that substantial molecular evolution of dcm genes has occurred beyond their horizontal transfer in the bacterial domain. Our study showed the power of pan-proteomics for quick characterization of new strains belonging to branches of the Tree of Life that are densely genome-sequenced.

Non-enzymatic reduction of Cr (VI) and it's effective biosorption using heat-inactivated biomass: A fermentation waste material.

The effectiveness of heat-inactivated fungal biomass a fermentation waste of newly isolated laccase enzyme producer Leiotrametes flavida was studied for Cr (VI) removal in water and applied for Cr (VI) removal from tannery effluent. Adsorption parameters pH, biomass concentration and contact time were optimized using Box-Behnken design of response surface methodology. The adsorption process fits the Langmuir isotherm. Thermodynamic and kinetic studies showed that the process is spontaneous at ambient temperature and followed the second-order kinetics model, respectively. The values of the kinetic model indicated that the adsorption process is a combination of physisorption and chemisorption. Chromium adsorption onto the biomass was confirmed by SEM-EDAX, FTIR, XPS and XRD analysis. XPS analysis confirmed the reduction of Cr (VI) to Cr (III). The amount of chromium adsorbed was 72.38 % and 68.33 % for water and effluent, respectively. Chromium adsorbed onto biomass was desorbed at pH 9 with 1 M NaOH. Total chromium desorbed was 61.40 and 59.38 percent from water and effluent, respectively. The amount of Cr (III) in the desorbed sample was 71 and 68 percent, respectively. The heat-inactivated biomass of Leiotrametes flavida is a suitable material for efficient Cr (VI) removal and detoxification.

Designing of New Optical Immunosensors Based on 2-Amino-4-(anthracen-9-yl)-7-hydroxy-4H-chromene-3-carbonitrile for the Detection of Aeromonas hydrophila in the Organs of Oreochromis mossambicus Fingerlings.

A one-pot greener methodology has been adopted for the synthesis of a simple 4H-chromene core-based fluorescent tag of (S)-2-amino-4-(anthracen-9-yl)-7-hydroxy-4H-chromene-3-carbonitrile (AHC), and its structure has been analyzed using NMR spectroscopy. The physicochemical properties of AHC were well-studied by UV-vis and fluorescent spectroscopy techniques. As a result of excellent emitting property (ϕ ≈ 0.75), it has been coupled with anti-AH through amide linkage, and the AHC-tagged anti-AH has been used as an immunoassay for the selective detection of Aeromonas hydrophila in the presence of interfering pathogens. Under optimized conditions, immunosensors could successfully quantify A. hydrophila from 4 to 736 CFU/mL, and the LOD was 2 CFU/mL. Saliently, the immunoassay has been successfully demonstrated for the analysis of A. hydrophila in the organs of Oreochromis mossambicusfingerlings, and results have shown a very good agreement with our optimized neat AH fluorimetric titration results.

Efficient Removal of Cadmium Using Edible Fungus and Its Quantitative Fluorimetric Estimation Using (Z)-2-(4H-1,2,4-Triazol-4-yl)iminomethylphenol.

Microbes accumulate heavy metals after adsorption or absorption. This study exhibited that Trametes versicolor can tolerate up to 5 mg/g concentration of cadmium. Change in fungus morphology due to cadmium along with its absorption were analyzed using SEM, XRD, and EDAX. Cadmium absorption usually increased with time, and it was determined quantitatively by a fluorimetry technique using a synthesized imine fluorophore as a specific probe and compared with results obtained from atomic absorption spectroscopy (AAS). The intensity of the cadmium-specific XRD peak gradually increased up to the seventh day, and the absorption by the organisms reduced the concentration of cadmium even from the effluent of the plating industry. After the seventh day, Trametes versicolor absorbed almost 0.300 mg/g concentration of cadmium as visualized under high content screening from the fluorescence appearance of hyphae. Hence it can be concluded that Trametes versicolor may play a key role in reducing cadmium from a contaminated environment.

Early maturation and liver necrosis in the fingerling stage of Oreochromis mossambicus due to BPA can cause an ecological imbalance.

We investigated the effect of Bisphenol-A (BPA) on the fingerlings of Oreochromis mossambicus collected from industrial waste. Fluorescence quenching assay using Rhodamine-B and mass detection assay using ESI-MS revealed that BPA was predominantly present in plastic industry effluent, where the fingerlings' ovaries exhibited early maturation. The histopathology of those fingerlings revealed a similar result. Both quantitative and qualitative data obtained by ELISA and FPLC showed elevated levels of vitellogenin in the fingerling stages after prolonged exposure to BPA present in the contaminated water. Our qRT-PCR data showed a subsequent increased expression of vitellogenin in those fingerlings obtained from contaminated effluent. FACS analysis suggested that BPA generated a significant amount of ROS in the livers of those fingerlings, leading to necrosis in hepatocytes.

Gold nanoparticles used as a carrier enhance production of anti-hapten IgG in rabbit: a study with azobenzene-dye as a hapten presented on the entire surface of gold nanoparticles.

The azobenzene moiety, well-known not only for its reversible cis-to-trans photoisomerization but also as a hapten, does not induce antibodies on its own, but it reacts with antibodies raised against conjugates with protein carriers. Hence we selected azobenzene dye as an indicator to assess the possibility of having gold nano-particles act as an immunological carrier instead of protein carriers. In rabbits, we confirmed an in vivo response against azobenzene dye presented on the entire surface of gold nanoparticles (azo-nanoparticles), where the gold nanoparticles appeared to play a role as a carrier for the hapten. A high yield of immunoglobulin G (IgG) against the azobenzene derivative took place in rabbits injected with azo-nanoparticles, whereas no increase in IgG was recognized in other rabbits treated solely with chemically equivalent azobenzene dye instead of azo-nanoparticles. Electron microscopy and surface plasmon resonance spectroscopy indicated that the IgG obtained specifically recognized the difference between the isomer conformations of the azobenzene moiety.

Synthesis of Ferrierite-Type Zeolite in the Presence of a Catalytic Amount of Pyrrolidine and Sodium Bis(2-ethyhlhexyl) Sulfosuccinate.

Synthesis of ferrierite (FER) type zeolite with varying Si to Al ratios in the presence of a catalytic amount of pyrrolidine and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in aqueous media is reported. The surfactant moieties direct pyrrolidine molecules in a particular fashion, resulting in a sixfold decrease in the required amount of template as compared to conventional procedure, for FER crystallization. The product obtained was highly crystalline and pure. In the presence of AOT alone, ferrierite co-crystallized with the ZSM-5 phase, indicating AOT is not acting as a structure-directing agent and a small concentration of pyrrolidine ( approximately 2 wt%) template is essential for the ferrierite crystallization. A scanning electron micrograph showed uniformity in crystals (average 2-3 µm) consisting of broad plate type morphology. The crystal structure of FER (AOT/Py) maintains structural integrity until about 1000 degrees C. FER (AOT/Py) has been further characterized by employing XRD, XRF, IR, and TG/DTA techniques. Copyright 2001 Academic Press.