ChemInform Abstract: A NOVEL REAGENT SYSTEM: MIXTURE OF PHOSPHORUS OXYCHLORIDE, ORTHOPHOSPHORIC ACID AND ANHYDROUS ZINC CHLORIDE FOR THE SYNTHESIS OF 1‐HYDROXYXANTHONES

The quantum amplified, photosensitized isomerization of a Dewar benzene reactant to a benzene product was used to create a visible image based on differential light scattering. The reactant and a UV triplet sensitizer were dispersed together as small particles in a solid, continuous matrix of gelatin, coated on a polyester film support. The refractive indexes of the particulate and continuous phases were initially approximately matched, leading to an essentially transparent appearance. After exposure to UV light (absorbed by the sensitizer), the change in refractive index resulting from the isomerization caused a significant mismatch in refractive index between the particles and the binder. In addition, the product partially crystallized. The outcome was an opaque texture in the coating. A pictorial image attributable to regions of high and low light scattering could be prepared by irradiation of the coating through a simple contact mask. The scattering texture forms spontaneously on irradiation, without any chemical processing or heating. The image is indefinitely stable in the absence of heat and UV light.

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“…Also, it is readily soluble in organic media. 1-Methoxyxanthen-9-one was synthesized by methylation of readily available 1-hydroxyxanthen-9-one …”

Section: Resultsmentioning

confidence: 99%

Creation of Light Scattering Images in a Polymer Film by Quantum Amplified Isomerization

Mis

Robello

2012

Chem. Mater.

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“…Many general methods for the synthesis of xanthones are known and have been reviewed (Afzal and Al-Hassan, 1980;Roberts, 1961). Among the most popular methods is the Michael-Kostanecki method, which was later modified by Grover et al (1955) and still later by Muchali et al (1985) and Nevrekar et al (1983). This method involves the reaction of an o-hydroxybenzoic acid with a polyhydric phenol in the presence of a dehydrating agent such as polyphosphoric acid, acetic anhydride, phosphorus oxychloride, or mixtures of these reagents.…”

Section: Resultsmentioning

confidence: 99%

“…Even though the yield was low, the same method, due to its simplicity, was used for the preparation of la in this work. Although 1-hydroxyxanthone has been synthesized by the Michael-Kostanecki method (Muchali et al, 1985;Nevrekar et al 1983), the yields are low and the possibility of contamination by 3-hydroxyxanthone exists. For these reasons we chose to carry out a regioselective synthesis of both the 1-hydroxy-and 7-chloro-1-hydroxyxanthones via the procedure shown in Figure 2.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and herbicidal activity of xanthones

Charlton¹,

Sayeed²,

Koh³

et al. 1990

J. Agric. Food Chem.

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Several substituted xanthones have been synthesized and tested for herbicidal activity. Both the classical Michael-Kostanecki method and a new regioselective method were used to prepare starting 1-hydroxyxanthones from which several 1-alkoxyxanthones were prepared. Among the compounds tested, herbicidal activity was greatest for 1-methoxyxanthone and l-(allyloxy)xanthone. Some species specificity was observed, particularly for l-methoxy-3-methylxanthone, which was more toxic to grasses than to broadleaf species.

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“…Xanthone (1), mp 173-174°C, obtained by fusing o-hydroxybenzoic acid and phenol [15]. Condensation of o-hydroxybenzoic acid and resorcinol (under various conditions) gave 1-hydroxyxanthone (3), mp 147-148°C [16] and 3-hydroxyxanthone (4), mp 245-246°C [17].…”

Section: Methodsmentioning

confidence: 99%

“…1,3-Dihydroxyxanthone (6), mp 254-256°C, obtained from o-hydroxybenzoic acid and phloroglucinol [16]. (5), mp 175-176°C, obtained by Ulmann condensation from guaiacol and 2-iodobenzoic acid [18] with subsequent cyclization of the diaryl ether in acetylchloride in the presence of H 2 SO 4 [19].…”

Section: Methodsmentioning

confidence: 99%

Hydrophobicity constants for several xanthones and flavones

et al. 2011

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The octanol-water distribution of several xanthones and flavones was studied. Their hydrophobicity constants (log P) were determined. The lipophilicity constants (S) of the substituents were calculated. The relationship between the structure and hydrophobicity constants of the gamma-pyrone derivatives was found.Xanthones and flavones are secondary plant metabolites and exhibit broad spectra of biological activity [1][2][3]. Therefore, the study of the physicochemical properties of these gamma-pyrone derivatives is attractive [4][5][6]. An important physicochemical property of biologically active compounds is the hydrophobicity constant, which determines their ability to penetrate cell membranes. Knowledge of this constant is a reliable predictor of the media in which the compound will accumulate in vivo, i.e., in lipids of cell membranes or in aqueous media.The hydrophobic properties of gamma-pyrone derivatives were not systematically studied before our research [7]. We previously determined the hydrophobicity constants of flavone and several of its monosubstituted derivatives [8]. Herein we present results from a study of the hydrophobic properties of several xanthones and disubstituted flavones.Flavones and xanthones that are isolated from plants are, as a rule, polysubstituted compounds. Therefore, we used simpler synthetic mono-, dihydroxy-, and methoxy-substituted analogs in additional to natural compounds and their modified derivatives in the study. This set of samples was studied because their biological activity is determined by differences in the number and location of the hydroxyls and methoxyls in the molecules [1,3,9].The octanol-water distribution of the compounds was studied. This system was selected because octanol mimics the cell-membrane lipid layer. Therefore, the hydrophobicity constants obtained in this system can be used for structure-activity correlations [10,11]. The distribution coefficients were calculated using the formula P = C o /C w , where C o and C w are the equilibrium molar concentrations of the compounds in the organic and aqueous phases [12].The concentrations of the compounds after equilibration were determined in each phase using UV spectroscopy. For this, plots of optical density vs. concentration at the analytical wavelengths were constructed beforehand. Figure 1 shows an example of UV spectra for three xanthones with different substituents.The wavelengths (O) at which the absorption was maximal were used as the analytical ones for xanthones with strong absorption in the range 250-265 nm: xanthone (1), 265 nm; 1-hydroxyxanthone (3), 250; 4-methoxyxanthone (5), 248; 1,7-dihydroxy-3,8-dimethoxyxanthone (7), 260; 1-hydroxy-2,3,4,5-tetramethoxyxanthone (8), 265; and 1-allyloxy-2,3,4,5-tetramethoxyxanthone (9), 250.

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ChemInform Abstract: A NOVEL REAGENT SYSTEM: MIXTURE OF PHOSPHORUS OXYCHLORIDE, ORTHOPHOSPHORIC ACID AND ANHYDROUS ZINC CHLORIDE FOR THE SYNTHESIS OF 1‐HYDROXYXANTHONES

Cited by 3 publications

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Creation of Light Scattering Images in a Polymer Film by Quantum Amplified Isomerization

Creation of Light Scattering Images in a Polymer Film by Quantum Amplified Isomerization

Synthesis and herbicidal activity of xanthones

Hydrophobicity constants for several xanthones and flavones

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