http://irgu.unigoa.ac.in/drs/handle/unigoa/5626 2026-08-31T08:30:11Z 2026-08-31T08:30:11Z Salgaonkar, L.N. Coelho, L.J. Fernandes, R. Kadam, H.K. Mandrekar, V.K. Naik, M.M. Chari, V.R. http://irgu.unigoa.ac.in/drs/handle/unigoa/7949 2026-08-21T10:27:16Z 2026-01-01T00:00:00Z

Guanidine hydrochloride catalyzed alternative synthesis of xanthenediones with broad spectrum quorum quenching activity Salgaonkar, L.N.; Coelho, L.J.; Fernandes, R.; Kadam, H.K.; Mandrekar, V.K.; Naik, M.M.; Chari, V.R. Xanthenediones are fused oxygen heterocycles with diverse biological properties. We herein report an efficient method for preparation of xanthenediones using aldehydes and diones with guanidine hydrochloride. This methodology demonstrated tolerance to diverse substitution on reactants giving products in good yields. In the present investigation, Thirty one xanthenedione derivatives were synthesised including eight new derivatives and screened for their potential to inhibit violacein and prodigiosin pigments synthesis in bioreporter bacteria Chromobacterium violaceum and Serratia marcescens respectively regulated by QS systems (CviI/R, and smaI/R). Four xanthenedione derivatives (4, 5, 30, 31) showed very promising Quorum quenching (QQ) activity by inhibiting QS regulated pigments (violacein and prodigiosin) production. When tested against clinical isolate Pseudomonas aeruginosa, xanthenedione derivatives showed significant reduction in biofilm formation, swarming motility, Pyocyanin and Rhamnolipid production controlled by Las and Pqs QS systems in dose dependent manner. Moreover, molecular docking studies supported our results with good binding affinity of -7.24, -7.83, -7.38 and -7.6 kcal/mol respectively to protein 4JVC (multiple virulence factor regulator MvfR/PqsR of Pqs QS system) of Pseudomonas aeruginosa. The present investigation highlights potential of xanthenediones to disrupt multiple QS systems (CviI/R, smaI/R, LasI/R and Pqs) and its suitability as drug to control MDR bacterial infections.

2026-01-01T00:00:00Z D'Souza, L.R. Swapna, V. Dhuri, S.N. http://irgu.unigoa.ac.in/drs/handle/unigoa/7934 2026-08-07T07:33:32Z 2026-01-01T00:00:00Z

Dimeric and Monomeric Cu(II) 2,2'-bipyrimidine dicarboxylates in distorted environments: Structural Diversity, Magneto- Structural Correlations and Additives in Thermolysis of Ammonium Nitrate D'Souza, L.R.; Swapna, V.; Dhuri, S.N. Two new copper(II) compounds, dimeric [Cu sub(2)(fum)(bpm) sub(2)(H sub(2)O) sub(2)(NO sub(3)) sub(2)] 1 and monomeric [Cu(ida)(bpm)].4H sub(2)O 2 from rigid (fum sup(2-)) and flexible (ida sup(2-)) dicarboxylates were structurally characterized as undergoing Jahn- Teller tetragonal distortions (Z- out) to form distorted square-based pyramidal geometries (0 less than torque 5 less than 1) forming a herring- bone (1) and columnar supramolecular motifs (2). Wavefunction and molecular orbital analysis for 1 and 2 revealed strong in- plane Pi- covalency (K// less than K┴ and g// less than or equal to 2.3) with Z- out elongation and significant nephelauxetic electron delocalization. For 2, the bonding parameter hierarchy: Alpha 2 (0.741) less than beta 12 (0.860) less than beta 2 (1.066) verified a highly anisotropic, distorted coordination geometry defined by strong, cooperative in- plane sigma and Pi- bonding interactions alongside a stable, weakly mixed out- of- plane Pi- network driven by subtle orbital adjustments. EPR and magnetic studies confirmed that the unpaired electron resides in the dx sup(2)-y sup(2) orbital, revealing the coexistence of weak ferromagnetic and antiferromagnetic interactions (phi=+ 5.504 and J=-13.7 cm sup(-1)) for dimeric 1 and 2 behaving as a simple monomeric paramagnet. Thermogravimetric and Kinetic modeling (Coats- Redfern) presented positive Delta H and Delta G values affirming a non- spontaneous endothermic process of AN decomposition by 1 and 2, with lower activation energy. Thus, warranting the role of 1 and 2 as effective, low temperature additives for the thermolysis of AN via the ionic pathway.

2026-01-01T00:00:00Z Kotkar, Gayatri Divakar http://irgu.unigoa.ac.in/drs/handle/unigoa/7929 2026-08-04T10:59:09Z 2024-05-01T00:00:00Z

Synthetic Transformation And Applications Of 5-Hydroxymethylfurfural And Cashew Nut Shell Liquid Kotkar, Gayatri Divakar

2024-05-01T00:00:00Z Viegas, Jeffrey L. http://irgu.unigoa.ac.in/drs/handle/unigoa/7918 2026-07-31T11:20:51Z 2025-08-01T00:00:00Z

Synthesis and characterization of non-heme 3d metal compounds for selected applications Viegas, Jeffrey L.

2025-08-01T00:00:00Z