http://dspace.cus.ac.in/jspui/handle/1/6384 2026-04-13T16:33:45Z http://dspace.cus.ac.in/jspui/handle/1/6397 Title: In situ mechanochemical synthesis of nitrones followed by 1,3-dipolar cycloaddition: a catalystfree, “green” route to cis-fused chromano[4,3-c] isoxazoles Authors: Bhutia, Zigmee T.; P., Geethika; Malik, Anurag; Kumar, Vikash; Chatterjee, Amrita; Roy, Biswajit Gopal; Banerjee, Mainak Abstract: An efficient and catalyst-free method for the synthesis of cis-fused chromano[4,3-c]isoxazoles via intramolecular 1,3-dipolar nitrone cycloaddition involving hand-grinding in a mortar-pestle has been developed. The mechanochemical agitation was sufficient for dehydrative nitrone formation by condensation of various O-allyl salicylaldehyde derivatives and alkyl/aryl hydroxylamines. The corresponding nitrones undergo intramolecular 1,3-dipolar cycloaddition leading to regioselective formation of cis-fused tetrahydrochromeno[4,3-c]isoxazole derivatives in high yields. The key features of this new method are cleaner reaction profiles, catalyst-free conditions, high yields, and short reaction times. 2015-01-01T00:00:00Z http://dspace.cus.ac.in/jspui/handle/1/6396 Title: Recognition of fluoride anions at low ppm level inside living cells and from fluorosis affected tooth and saliva samples Authors: Ghosh, Pritam; Roy, Biswajit Gopal; Mukhopadhyay, Subhra Kanti; Banerjee, Priyabrata Abstract: A simple Schiff base chemosensor 2-((2-(2,4-dinitro phenyl)hydrazono)methyl)-4-nitrophenol (L) has been developed as a colorimetric and fluorimetric ‘turn on’ sensor for fluoride (F−). F− recognition at ppm levels from mouth rinses and a toothpaste water solution has been successful. Significantly, L can detect F− from fluorosis affected tooth and saliva samples by similar colorimetric changes. A test kit for F− detection from a DMSO–water (1 : 1) mixture is also engineered. Intracellular F− from pollen grains of Techoma stans and Candida albicans (a diploid fungus), grown in 10−6 (M) F− contaminated water has been successfully detected under a fluorescence microscope. 2015-01-01T00:00:00Z http://dspace.cus.ac.in/jspui/handle/1/6395 Title: A simple and dual responsive efficient new Schiff base chemoreceptor for selective sensing of F− and Hg2+: application to bioimaging in living cells and mimicking of molecular logic gates Authors: Chowdhury, Additi Roy; Ghosh, Pritam; Roy, Biswajit Gopal; Mukhopadhyay, Subhra Kanti; Mitra, Partha; Banerjee, Priyabrata Abstract: A novel colorimetric hydrazine-functionalized Schiff base chemoreceptor, NPMP, was synthesized following a simple one-step Schiff base condensation pathway. NPMP showed selective colorimetric change from faint yellow to yellowish orange in the presence of biologically ubiquitous fluoride (F−). It also showed a ‘turn off’ fluorescent response in the presence of F− that could effectively distinguish it from all anions tested except acetate. Acetate (OAc−) caused a weak response, while other anions like chloride, bromide, iodide, phosphate, hydrogen sulfate and nitrate did not have any observable effect on the NPMP receptor (E)-4-nitro-2-((2-(perfluorophenyl)hydrazono)methyl)phenol. Recognition of F− in the presence of NPMP can be explained in light of multiple H-bonding interactions, as well as acid–base interactions between host receptor and guest F−. Interestingly, NPMP also showed enormous potential as a staining agent in determining the presence of low levels of intracellular fluoride. Moreover, it was found that in NPMP⋯F− solutions, incorporation of Hg2+ showed observable optical changes, revealing that this compound is a smart material. Optical responses of NPMP can mimic a molecular logic gate (INHIBIT gate). This can be interpreted as a combination of an AND gate with a NOT function. It also represented a potential ‘Write–Read–Erase–Read’ memory function reflecting multi-writing ability. 2015-01-01T00:00:00Z http://dspace.cus.ac.in/jspui/handle/1/6394 Title: Synthesis of novel D-glucose based anionic bolaamphiphiles and their catalytic application in 1,3-dipolar nitrone cycloaddition reactions Authors: Kumar, Vikash; Chatterjee, Amrita; Roy, Biswajit Gopal; Banerjee, Mainak Abstract: Three d-glucose based bolaamphiphiles have been synthesized by a simple and efficient synthetic methodology utilizing the free C-3 hydroxyl group of diisopropylidene glucose. The resulting bolaamphiphiles showed unique aggregation behavior in aqueous solution, e.g. transformation of vesicle to tubular morphology on aging. The chiral hydrophobic interior of these vesicles was utilized as tiny reaction vessels to carry out 1,3-dipolar nitrone cycloadditions in water. The corresponding isoxazolidine derivatives were formed with high diastereoselectivity in several cases. The bolaamphiphile with 12 carbon spacer (5c) showed better diastereoselectivity among the rest with just 2 mol% of catalyst loading and can be reused. 2017-01-01T00:00:00Z