The dark-green solid was further purified by silica gel chromatography (CH 2Cl 2/CH 3CH 2OH = 200:1, 20:1 v/v) to give green microcrystalline, the intermediate of the second step. After that, the resulting mixture was put into the refrigerator immediately to stop the reaction and then distilled under reduced pressure to obtain a dark-green solid. 94%.īoth the red solid (2.5 g, 6.65 mmol) obtained in the first step and equal number of moles of fisher aldehyde (1.34 g, 6.65 mmol) were dissolved directly in acetic anhydride (35.0 mL), refluxed for 0.5 h under stirring. Perchloric acid (2.0 mL, 70%) was then added and the resulting precipitate was filtered, washed several times with cold water and dried in the air to give a red solid. After the addition was completed, the reaction mixture was heated at 90 ☌ for 3 h, cooled down and poured onto ice (150.0 g). Then, 2-(4-diethylamino-hydroxybenzoyl) benzoic acid (3.00 g, 9.6 mmol) was added in portions under vigorous stirring. The title compound was obtained from cyclohexanone by a four-step reaction.įirst step: Cyclohexanone (1.98 mL) was added dropwise to concentrated sulfuric acid (20.0 mL) under ice-bath condition. The title compound was synthesized according to the literature method. AtomĪOccupancy: 0.830(5), bOccupancy: 0.170(5).Īll reagents and starting materials were commercially available and used as received. Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2).