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bis-2,5-([5-(nitrooxy)pentanoyl]oxy)benzenesulfonic acid calcium salt[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
With dmap; In ethanol; for 1.0h;
Example 3: Preparation of nitrosated 2,5-dihydroxybenzene compound VII (Bis-2, 5-[(5-nitrooxy) pentanoyl]oxy}benzene sulfonic acid calcium salt)VII <n="80"/>; <strong>[20123-80-2]Calcium dobesilate</strong> (3g) was dissolved in 30 ml of ethanol and 5-nitrooxy- pentanoic acid 4-nitrophenyl ester (9.7 g) was added. Acetone (30 ml) was added to dissolve the reaction mixture. After obtaining clear solution, DMAP (0.42 g) was added to the reaction mixture and it was stirred for 1 h. A black green solution was obtained with a small amount of solid. The solid was filtered and the filtrate was stirred for 24 h at rt. The reaction was monitored by TLC and upon completion of reaction it was concentrated. Ethanol was added to the crude mass and it was stirred for 1 h. Compound VII (2,5NO-BS) is obtained as a white fluffy solid. Yield: 1.8 g. M.P: 145 - 147 0C, 1H NMR (DMSO-J6, 400 MHz): deltal.68 -1.79 (4H, m), 2.55 (2H, t, J = l. Hz), 2.66 (2H, t, J = l. Hz), 4.54 - 4.58 (4H, m), 7.08 (IH, d, J = 8.8 Hz), 7.12 (IH, d, J = 8.8 Hz), 7.41 (IH, d, J = 2.5 Hz). MS: m/z 479.0 (M+-K).
With sulfuric acid; calcium carbonate; In water; at 20.0℃; for 0.25h;
Fifteen grams (0.136 mol) of hydroquinone was added under stirring into 60 ml of sulfuric acid portion wise for 1 hour. Stirring was continued until the starting material was completely dissolved. The temperature during this process did not exceed 45 C. This solution of crude 2,5-dihydroxybenzenesulfonic acid (1) in sulfuric acid was poured under stirring into 1500 ml of water and 150 g (1.5 mol) of calcium carbonate was then added portion wise under vigorous stirring. Stirring continued for an additional 15 min at room temperature. Then, the suspension was shortly heated to a boil and immediately filtered by suction filtration. The filtrate containing crude (2) was then divided into three equal volume portions. Calcium dobesilate (2).The first portion was slowly concentrated by evaporation on a vacuum evaporator at a temperature that did not exceed 42 C. A white precipitate formed during evaporation was filtered off. The filtrate was evaporated to dryness. The residue was dried under reduced pressure (0.7 kPa) at 40 - 42 C over diphosphorus pentaoxide for 7 days.The yielded calcium 2,5-dihydroxybenzenesulfonate (2) was identified by 1H-NMR as pentahydrate. White solid; Yield: 94 %.
Magnesium dobesilate (4). In total, 4.38 g (0.036 mol) of anhydrous magnesium sulfate was added under stirring to the second portion of the crude (2) solution at room temperature.The mixture was stirred for an additional 30 min and then heated to a boil for a short period of time. The formed calcium sulfate precipitate was removed by suction filtration of the hot suspension. The filtrate was slowly concentrated by evaporation on a vacuum evaporator at a temperature that did not exceed 42 C. A white precipitate formed during evaporation was filtered off. The filtrate was evaporated to dryness. The residue was dried under reduced pressure (0.7 kPa) at 40 - 42 C over diphosphorus pentaoxide for 7 days. The yielded magnesium 2,5-dihydroxybenzenesulfonate (4) was identified by 1H-NMR as decahydrate.White solid; Yield: 72 %
With zinc(II) sulfate heptahydrate; at 20.0℃; for 0.5h;
Zinc dobesilate (5). In total, 6.53 g (0.023 mol) of zinc sulfate heptahydrate was added under stirring to the third portion of the crude (2) solution at room temperature. The mixture was stirred for an additional 30 minutes and then heated to a boil for a short period of time.The formed calcium sulfate precipitate was removed by suction filtration of the hot suspension. The filtrate was slowly concentrated by evaporation on a vacuum evaporator at a temperature that did not exceed 42 C. A white precipitate formed during evaporation was filtered off. The filtrate was evaporated to dryness. The residue was dried under reduced pressure (0.7 kPa) at 40 - 42 C over diphosphorus pentaoxide and protected from light for 7days. The yielded zinc dobesilate (5) was identified by 1H-NMR as octahydrate. Pale yellow solid. Yield: 80 %.
With dihydrogen peroxide; horseradish peroxidase; phenol; In aq. phosphate buffer; dimethyl sulfoxide; at 20.0℃;pH 7.0;Enzymatic reaction;Kinetics;
General procedure: Reactions were carried out at room temperature in 3ml of 50mM sodium phosphate buffer, pH 7.0 containing 1% (v/v) DMSO, for 50 or 100 muM homogentisic acid, gentisic acid, <strong>[20123-80-2]calcium dobesilate</strong> or etamsylate with 50 muM H2O2 in the absence or presence of HRP at either 0.4 mug/ml (0.08U/ml) or 2 mug/ml (0.4U/ml) concentration. Additionally, to accelerate the oxidation of gentisic acid, <strong>[20123-80-2]calcium dobesilate</strong> and etamsylate reactions were carried out with 100 muM H2O2 in the presence of 20 muM phenol and 2 mug/ml (0.4U/ml) of HRP. Reactions were initiated by the addition of the enzyme. UV/Vis spectra from 230 to 680 nm were recorded immediately after mixing the reagents and then at 1min intervals for 10-30 min. Absorbance at 247 nm was measured in separate experiments. Hydrogen peroxide consumption was measured as described above. All experiments were performed at least in triplicates.
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