Hydrochloric Acid → 2-Hydroxy-5-methylbenzophenone

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

##STR19## 38 g (0.3 mol) of dimethylcyclohexylamine and 27 g (0.25 mol) of p-cresol in 150 ml of chlorobenzene were initially taken. 35.1 g (0.25 mol) of benzoyl chloride were added dropwise over one hour, the temperature increasing to 50° C. After cooling to room temperature, the suspension was added to 100 ml of water in order to separate off the dimethylcyclohexylamine hydrochloride. The organic phase was separated off and was dried by partial distillation. 33 g (0.25 mol) of aluminum trichloride were then added a little at a time at room temperature in the course of 30 minutes. During this procedure, the internal temperature increased to 50° C. The batch was stirred at 130° C. for about 10 hours until the evolution of HCl gas had ceased. After cooling to 60° C., the reaction mixture was poured onto ice water. The phases were separated and the aqueous phase was extracted twice with chlorobenzene. The combined organic phases were dried over magnesium sulfate and then evaporated down. 43 g (corresponding to a yield of 81%) of 2-hydroxy-5-methylbenzophenone were obtained. 25 g (0.12 mol) of the compound were then dissolved in 150 ml of methanol, and 4.1 g of sodium hydroxide in 30 ml of methanol were then added. The refluxing reaction mixture was stirred for 3 hours and then evaporated down in a rotary evaporator. 27 g (corresponding to a yield of 98%) of the title compound were obtained in the form of an orange solid.

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