Sulfuric Acid → 2-Hydroxy-3,4-dimethyl-9H-thioxanthen-9-one

Participants

Reaction Steps

Concentrated sulphuric acid (300 ml) was slowly added to thiosalicylic acid (30.9 g) and the mixture was stirred for 5 minutes to ensure thorough mixing. To the stirred mixture was added slowly over a period of 30 minutes 2,3-dimethyl-phenol (138 g). After the addition, the mixture was stirred at room temperature for 1 hour, and then at 80° C. for 2 hours, after which it was left to stand at room temperature overnight. The resulting mixture was poured carefully with stirring into 10 times its volume of boiling water after which it was boiled for a further five minutes, cooled, and filtered. The residue was recrystallised from acetone to give 2-hydroxy-3,4-dimethyl-thioxanthone as a yellow product.

Provenance & Evidence