Potassium Carbonate → 1-(4-Hydroxyphenyl)-4-(benzoxazol-2-yl)piperazine

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A mixture of 5.11 g (15 mmol) of 1-(4-hydroxyphenyl)piperazine dihydrobromide, 2.46 g (16 mmol) of 2-chlorobenzoxazole and 2.18 g (15.8 mmol) of powdered K2CO3 in 55 ml of absolute N,N-dimethylformamide was warmed to 85° C., and 345 mg of powdered K2CO3 were added with stirring under a nitrogen atmosphere in each case after 10 minutes, after a further 25 minutes and after a further 60 minutes (total addition of 1.035 g (7.5 mmol) of K2CO3). The mixture was stirred for a further 3 hours at 85° C., the DMF was substantially removed by distillation in an oil-pump vacuum in a rotary evaporator, the crystalline residue was mixed with 50 ml of water, and this mixture was shaken for 15 minutes. The mixture was then filtered under suction and the filter residue was washed with water and dried in vacuo. 4.30 g (97% of theory) of pure 1-(4-hydroxyphenyl)-4-(benzoxazol-2-yl)piperazine, melting point 161°-3° C., were obtained,

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