Relationships observed in the structure and spectra of uracil and its 5-substituted derivatives

Palafox, M. Alcolea; Tardajos, G.; Guerrero‐Martínez, Andrés; Vats, J. K.; Joe, Hubert; Rastogi, V. K.

doi:10.1016/j.saa.2009.12.042

Cited by 40 publications

(6 citation statements)

References 82 publications

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“…The spectral band centered at 1245 cm –1 can be undoubtedly assigned to C–F stretching (υ (C–F) ), in agreement with data reported in the literature for 5-FU molecules in Ar matrix . In addition, the shoulder of this peak at 1225 cm –1 may reveal the coexistence of some dimeric forms. , The same dualism can also be inferred by the spectral shape of 5-FU in the 1800–1500 cm –1 spectral region, where characteristic CO and CC vibrations are found. Specifically, the 1774 and 1723 cm –1 bands are mostly associated with carbonyl stretching of C2O (υ (C2O) ) and C4O (υ (C4O) ) groups, whereas the mode centered at 1659 cm –1 is mostly due to C5C6 bond (υ (C5C6) ). , The broad nature of this latter band let us suppose the presence of other contributions, such as the spectral component at ∼1670 cm –1 obtained by second derivative analysis (data not shown), likely due to some hydrogen bonding between 5-FU molecules themselves or with the solvent. , This is in agreement also with UV Raman scattering measurements, performed on hydrated 5-FU (Figure a).…”

Section: Results and Discussionsupporting

confidence: 89%

“…In addition, the shoulder of this peak at 1225 cm –1 may reveal the coexistence of some dimeric forms. , The same dualism can also be inferred by the spectral shape of 5-FU in the 1800–1500 cm –1 spectral region, where characteristic CO and CC vibrations are found. Specifically, the 1774 and 1723 cm –1 bands are mostly associated with carbonyl stretching of C2O (υ (C2O) ) and C4O (υ (C4O) ) groups, whereas the mode centered at 1659 cm –1 is mostly due to C5C6 bond (υ (C5C6) ). , The broad nature of this latter band let us suppose the presence of other contributions, such as the spectral component at ∼1670 cm –1 obtained by second derivative analysis (data not shown), likely due to some hydrogen bonding between 5-FU molecules themselves or with the solvent. , This is in agreement also with UV Raman scattering measurements, performed on hydrated 5-FU (Figure a). The Raman profile of 5FU (solid line) can be decomposed into three major contributions, centered at ∼1714, ∼1685, and ∼1659 cm –1 , assigned to υ (C2O) , υ (C4O) , and υ (C5C6) , respectively, strengthening the hypothesis that the solvent may play a role.…”

Section: Results and Discussionmentioning

confidence: 63%

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Lyotropic Liquid-Crystalline Nanosystems as Drug Delivery Agents for 5-Fluorouracil: Structure and Cytotoxicity

et al. 2017

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Lyotropic cubic liquid-crystalline systems have received increasing attention due to their unique microstructural and physicochemical properties as efficient nanocarriers for drug delivery. We report the preparation and characterization of bulk phases and cubosome dispersions of phytantriol loaded with the anticancer drug 5-fluorouracil, in neutral and anionic forms. In both cases, a Pn3m cubic phase was observed. The phytantriol phase behavior can be influenced by the addition of ionic agents, and, to this purpose, a positively charged lipid, such as N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride salt (DOTAP), was included in the studied formulations. It was found to induce a variation of the spontaneous membrane curvature of the phytantriol lipid bilayer, generating a transition from the Pn3m to the Im3m cubic phase. When 5-fluorouracil, in its anionic form (5-FUs), was encapsulated in these latter systems, a further transition to the H hexagonal phase was observed as a consequence of the formation of a complex phytantriol/DOTAP/5-FUs. The physicochemical characterization was performed with various complementary techniques including synchrotron small-angle X-ray scattering, dynamic light scattering, and attenuated total reflection Fourier transform infrared and UV resonance Raman spectroscopies. Encapsulation of 5-fluorouracil in the corresponding nanodispersions was evaluated, and their in vitro cytotoxicity was assessed in MDA-MB-231 cell line. Phytantriol cubosomes containing 5-fluorouracil showed a higher toxicity compared with the bare drug solution, and hence they represent potential nanocarriers in the delivery of 5-fluorouracil for cancer therapy.

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Section: Results and Discussionsupporting

confidence: 89%

Section: Results and Discussionmentioning

confidence: 63%

Lyotropic Liquid-Crystalline Nanosystems as Drug Delivery Agents for 5-Fluorouracil: Structure and Cytotoxicity

et al. 2017

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“…Fourier transform infrared spectroscopy (FTIR) gives a molecular level picture about 5-FU self-assembling nature in different DMSO-water mole fractions (Figure S7). The stretching vibrations of two −CO groups of 5-FU emerge at 1723 and 1663 cm –1 when it is present in the nonfibrillar form. , We have obtained similar stretching frequencies where no fibrils are formed. However, after fibril formation at χ DMSO ≈ 0.15, the peak value appear at 1690 cm –1 for both −CO groups, signifying that two carbonyl groups become indistinguishable as reported earlier .…”

Section: Resultssupporting

confidence: 63%

Selective Self-Assembly of 5-Fluorouracil through Nonlinear Solvent Response Modulates Membrane Dynamics

et al. 2020

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Controllable self-assembly and understanding of the interaction between single metabolite fibrils and live-cell membranes have paramount importance in providing minimal treatment in several neurodegenerative disorders. Here, utilizing the nonlinear nature and peculiar hydrogen bonding behavior of the dimethyl sulfoxide (DMSO)−water mixture, the selective selfassembly of a single metabolite 5-fluorouracil (5-FU) is achieved. A direct correlation between water availability and selective selfassembly of 5-FU is ratified from the excited-state dynamics. The specific fibrillar structures of 5-FU exhibit a great potential to modulate live cell membrane fluidity and model membrane lipid distribution. After 5-FU fibril addition, a disorder of H-bonded water molecules arises several layers beyond the first hydration shell of the polar headgroups, which essentially modifies interfacial water structure and dynamics. Overall, our results shed light on the role of solvent to govern specific self-assembly and also lay the foundation accounting for the earlier stage of several diseases and multidrug resistance.

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“…The six-membered heteroatom ring of uracil is planar, resembling aromatic molecules of benzene or pyridine. Due to its importance in nature and interesting biological activities, there have been many theoretical and experimental studies on uracil and its derivatives, for example, as reported in references [18,[22][23][24][25][27][28][29][30][31][32][33]. The main scientific problems analyzed were structure [26,34,35], energetics [34,36,37], vibrational [27][28][29][30][31]38] and NMR spectra [33,[39][40][41].…”

Section: Figurementioning

confidence: 99%

Factors Governing the Chemical Stability and NMR Parameters of Uracil Tautomers and Its 5-Halogen Derivatives

et al. 2020

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We report on the density functional theory (DFT) modelling of structural, energetic and NMR parameters of uracil and its derivatives (5-halogenouracil (5XU), X = F, Cl, Br and I) in vacuum and in water using the polarizable continuum model (PCM) and the solvent model density (SMD) approach. On the basis of the obtained results, we conclude that the intramolecular electrostatic interactions are the main factors governing the stability of the six tautomeric forms of uracil and 5XU. Two indices of aromaticity, the harmonic oscillator model of aromaticity (HOMA), satisfying the geometric criterion, and the nuclear independent chemical shift (NICS), were applied to evaluate the aromaticity of uracil and its derivatives in the gas phase and water. The values of these parameters showed that the most stable tautomer is the least aromatic. A good performance of newly designed xOPBE density functional in combination with both large aug-cc-pVQZ and small STO(1M)−3G basis sets for predicting chemical shifts of uracil and 5-fluorouracil in vacuum and water was observed. As a practical alternative for calculating the chemical shifts of challenging heterocyclic compounds, we also propose B3LYP calculations with small STO(1M)−3G basis set. The indirect spin–spin coupling constants predicted by B3LYP/aug-cc-pVQZ(mixed) method reproduce the experimental data for uracil and 5-fluorouracil well.

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Relationships observed in the structure and spectra of uracil and its 5-substituted derivatives

Cited by 40 publications

References 82 publications

Lyotropic Liquid-Crystalline Nanosystems as Drug Delivery Agents for 5-Fluorouracil: Structure and Cytotoxicity

Lyotropic Liquid-Crystalline Nanosystems as Drug Delivery Agents for 5-Fluorouracil: Structure and Cytotoxicity

Selective Self-Assembly of 5-Fluorouracil through Nonlinear Solvent Response Modulates Membrane Dynamics

Factors Governing the Chemical Stability and NMR Parameters of Uracil Tautomers and Its 5-Halogen Derivatives

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