Sulfuric Acid → Methylthioxanthone

참여 물질

반응 조건

반응 단계

Into an Erlenmeyer flask was charged 139 g of sulfuric acid, and 10 g of dithiosalicylic acid (Wako Pure Chemical Industries, Ltd.) was added thereto. After stirring at room temperature (about 25° C.) for 1 hour and then cooling in an ice bath, a cooled solution was obtained. Subsequently, 25 g of toluene was dropped slowly while the temperature of the cooled solution was kept at 20° C. or lower, and then the temperature was returned to room temperature (about 25° C.) and stirring was continued for additional 2 hours, so that a reaction liquid was obtained. While 815 g of water contained in a beaker was being stirred, the reaction liquid was added thereto slowly, and then a precipitated yellow solid was collected by filtration. The yellow solid was dissolved in 260 g of dichloromethane and 150 g of water was added. Moreover, 6.7 g of 24% aqueous KOH solution was added to make the aqueous layer alkaline, followed by stirring for 1 hour. Then the aqueous layer was removed by a separatory operation and the organic layer was washed with 130 g of water three times. Subsequently, the organic layer was dried over anhydrous sodium sulfate and then the solvent (dichloromethane) was distilled away, so that 8.7 g of intermediate (10) (yellow solid) was obtained. As a result of an analysis by 1H-NMR {300 MHz, DMSO-d6, δ (ppm): 8.4 (d, 1H), 8.2 (s, 1H), 7.8-7.7 (m, 2H), 7.7-7.5 (m, 3H), 2.4 (s, 3H)}, it was confirmed that intermediate (10) was a mixture (molar ratio 2:1) of 2-methylthioxanthone and 3-methylthioxanthone.

출처 및 근거