Structural basis for molecular recognition, theoretical studies and anti-bacterial properties of three bis-uracil derivatives

Design, Synthesis, and Characterization of Novel Bis-Uracil Chitosan Hydrogels Modified with Zinc Oxide Nanoparticles for Boosting Their Antimicrobial Activity

A new series of hydrogels was successfully prepared by incorporating various substituted bisuracil (R-BU) linkages between chitosan Schiff's base chains (R-BU-CsSB) and between chitosan chains (R-BU-Cs). After protection of the amino groups of chitosan by benzaldehyde, yielding chitosan Schiff's base (CsSB), the reaction with epichlorohydrin was confined on the -OH on C6 to produce epoxy chitosan Schiff's base (ECsSB), which was reacted with R-BU to form R-BU-CsSB hydrogels, and finally, the bioactive amino groups of chitosan were restored to obtain R-BU-Cs hydrogels. Further, some R-BU-Cs-based ZnO nanoparticle (R-BU-Cs/ZnONPs) composites were also prepared. Appropriate techniques such as elemental analysis, FTIR, XRD, SEM, and EDX were used to verify their structures. Their inhibition potency against all the tested microbes were arranged as: ZnONPs bio-composites > R-BU-Cs hydrogels > R-BU-CsSB hydrogels > Cs. Their inhibition performance against Gram-positive bacteria was better than Gram-negative ones. Their minimum inhibitory concentration (MIC) values decreased as a function of the negative resonance effect of the substituents in the aryl ring of R-BU linkages in the hydrogels. Compared with Vancomycin, the ZnONPs bio-composites showed superior inhibitory effects against most of the tested Gram-negative bacteria, all inspected Gram-positive ones, and all investigated fungi.

Synthesis opto-electronic characterization and NLO evaluation of 6-methyl 5-nitro Uracil crystal using XRD, spectroscopic and theoretical tools

The organic composite crystal for 6-methyl 5-nitro Uracil was grown using slow-evaporation method and the crystal quality was checked by observing the peaks in XRD pattern. The molecular structure of 6-methyl 5-nitro Uracil was used to find crystal parameters for determining NLO activity. The appropriate electronic geometrical structure was keenly noted and the transitional energy exchange was studied and thereby fine-tuning of crystal performance was made by adopting suitable electron-accepting and with-drawing substitutional groups. The crystal parameters; a≠b≠c confirmed the orthorhombic lattice pattern. The space group was found as P21/a and Transparency range was observed as 409-1256 nm. The laser measurements were made and laser Damage threshold was estimated at 10 ns[1.08-3 GW/cm2]. The scattering characteristics of bond networks over the molecule were observed by studying vibrational characteristics of elemental bonds. The hybrid calculations on DFT methods were made using B3LYP/6-311++(D,P) basis set. The chemical shift was observed and retracing chemical potential was identified from the parametric oscillation. The frontier molecular interactions between ground and excited orbital lobe overlapping segments were noted and type of interaction system was identified. The electronic and protonic transfer energy was measured and the origination point of equivalent chemical potential was acknowledged. The NBMO profile was keenly grafted and the transitional energy was measured at every consumed electronic energy band. The vibrational circular dichroic image for all vibrational regions was sketched and the rate of transmission and absorption ratio was verified from peak intensity.

Molecular Modeling Studies of Some Uracil and New Deoxyuridine Derivatives

Molecular modeling results reported in this paper are crucial in highlighting the quantitative relationship between the optimized structure and computed molecular properties related to four newly synthesized uracil derivatives with promising biological potential as anticancer bioactive agents. Moreover, 5-fluorouracil (5-FU) and its tautomers and thiouracils molecular properties are studied and correlated with their biological activities. The great medical importance of these and similar molecular systems requires research on their quantitative structure-activity relationships (QSAR) in order to further improve our knowledge about how receptor binding, selectivity, and pharmacological effects are achieved. Modeling is performed in the ground and the first singlet excited states using density functional theory (DFT) and its time-dependent extension (TD-DFT), respectively.