A theoretical and experimental study on the structure and dipole moment of phloroglucinol in ethanol

Rudyk, Roxana; Molina, M.A.A.; Yurquina, Alicia; Gómez, María Inés; Blanco, Susana; Ferretti, F.H.

doi:10.1016/j.theochem.2003.11.050

Cited by 22 publications

(6 citation statements)

References 29 publications

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“…The energy of the lowest energy conformer is 2.641/HF, 2.794/HF+, 3.921/DF, 4.127/DF+, 1.881/MP, and 1.140/MP+ lower for B‐ET6, where the first IHB forms on the same side as R′ and the OCH 3 methyl is oriented downward. In B‐ET2, the first IHB can only form with H17 and the OCH 3 methyl is perpendicular to the plane to minimize steric hindrances with both R and R′; like for phenol OH,19 perpendicularity of the OC bond of OCH 3 to the plane is energetically unfavorable. The energy difference between the lowest energy conformers of B‐P3‐ET2 and B‐P3‐ET6 increases to 6.292, likely because of two effects of the bulkier R′: greater steric hindrances with the OCH 3 methyl in B‐P3‐ET2 and greater energy of the first IHB in B‐P3‐ET6, where it forms on the same side as R′.…”

Section: Calculations and Resultsmentioning

confidence: 99%

The conformational preferences of acylphloroglucinols—a promising class of biologically active compounds

Kabanda

Mammino

2012

Int J of Quantum Chemistry

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Acylphloroglucinols are a broad class of phloroglucinol derivatives characterized by the presence of a COR group, where R is more often an alkyl chain. They are largely present in natural sources and exhibit a variety of biological activities, including antibacterial, antiviral, antifungal, antitumor, antioxidant, and antimalarial. This work reports the results of a systematic conformational study (in vacuo, chloroform, acetonitrile, and water) of a representative number (118) of actual and model acylphloroglucinol structures, considering the most common R chains and investigating conformational preferences and relative energies as well as the influence of specific structural features characterizing significant subsets of compounds. The study aimed at identifying patterns for conformational preferences and at singling out the conformational aspects more closely related to the individuality of different structures, as these are expected to be more closely linked to the differences in the biological activities of different compounds. The results highlight patterns enabling reliable predictions of the conformational preferences of acylphloroglucinol molecules.

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Section: Calculations and Resultsmentioning

confidence: 99%

The conformational preferences of acylphloroglucinols—a promising class of biologically active compounds

Kabanda

Mammino

2012

Int J of Quantum Chemistry

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“…It is showed by the absorbance of ethanol solvent is higher than the distilled water solvent because the hydroxyl group of ethanol can interact with the hydroquinone by the hydrogen bonding. The interaction between ethanol and hydroquinone formed the complex by the hydrogen bonding donor [12].…”

Section: Resultsmentioning

confidence: 99%

“…Figure 5 (a) shows the signal slightly decreased with the longer coil. The longer coil will maximize the reaction between phloroglucinol and hydroquinone by the hydrogen bond from the hydroxyl group of phloroglucinol and hydroquinone [12]. When the mixed solution in coil 1 was reacted with the sodium hydroxide, the complex formation will not be maximum and decrease the signal.…”

Section: Optimization Of Mixing Coilmentioning

confidence: 99%

Optimization of Flow Injection (FI) – Spectrophotometry for Hydroquinone Analysis

Fahmi

Sulistyarti

Mulyasuryani

et al. 2019

J. Pure App. Chem. Res.

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Hydroquinone is one of the phenolic compounds used in various cosmetic products for skin lightening as it can inhibit tyrosinase enzyme in producing melanin. However, hydroquinone is classified as a toxic compound, therefore, several countries such as Africa, Canada, and Indonesia prohibits hydroquinone usage in cosmetics. This research was focused on the development of a method for hydroquinone analysis using flow injection (FI) combined with spectrophotometry based on the reaction of hydroquinone with phloroglucinol in alkaline condition producing orange complex detected at 493 nm. The FI method was optimized based on operational factors and chemical factors in order to achieve sensitivity. The maximum sensitivity of FI method was achieved under operational condition of 100 µL sample volume, 100 cm mixing coil 1, 50 cm mixing coil 2 and 2.8 mL/min with the chemical condition of 0.005 mol/L NaOH and 0.001 mol/L phloroglucinol. Under these optimum conditions, the proposed method showed linearity in the range concentration of 2-80 mg/L and the method was applied to cosmetic sample with acceptable recovery.

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“…They are dispersive in nature and, therefore, they can be taken into account only by computational These studies clearly highlighted features related to the acylphloroglucinol unit and, therefore, appearing in all ACPL molecules (besides specific features associated with functions that may be present in the R* or Rˆsubstituents). The general features comprise the dominant role of the intramolecular hydrogen bond (IHB) between the sp 2 O of the acyl group and a neighbouring phenol OH (termed 'first IHB') [5][6][7]10,11], and the nonnegligible influence of the orientation of the phenol OHs [6,7,12] and of the weaker C-H•••O IHBs [8].…”

Section: Introductionmentioning

confidence: 99%

Correlation Effects in Trimeric Acylphloroglucinols

Mammino

2021

Computation

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Trimeric acylphloroglucinols (T-ACPLs) are a subclass of the large class of acylphloroglucinols—derivatives of 1,3,5-trihydroxybenzene containing an R–C=O group. T-ACPL molecules contain three acylphloroglucinol moieties linked by methylene bridges. Many of them are present in natural sources and exhibit biological activities, often better than the corresponding activities of monomeric acylphloroglucinols. All the stable conformers of T-ACPLs contain seven intramolecular hydrogen bonds, which constitute the dominant stabilising factors. A total of 38 different T-ACPLs, including both naturally occurring and model molecules, have been calculated at the HF and DFT/B3LYP levels. The DFT/B3LYP calculations were carried out both without and with Grimme’s dispersion correction, to highlight the dispersion (and, therefore, also electron correlation) effects for these molecules. The roles of dispersion are evaluated considering the effects of Grimme’s correction on the estimation of the conformers’ energies, the description of the characteristics of the individual hydrogen bonds, the conformers’ geometries and other molecular properties. Overall, the results offer a comprehensive overview of the conformational preferences of T-ACPL molecules, their intramolecular hydrogen bond patterns, and the correlation effects on their properties.

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A theoretical and experimental study on the structure and dipole moment of phloroglucinol in ethanol

Cited by 22 publications

References 29 publications

The conformational preferences of acylphloroglucinols—a promising class of biologically active compounds

The conformational preferences of acylphloroglucinols—a promising class of biologically active compounds

Optimization of Flow Injection (FI) – Spectrophotometry for Hydroquinone Analysis

Correlation Effects in Trimeric Acylphloroglucinols

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