Water → HCID 136090584, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of 9.7 g of the compound of Example 1 in 70 ml of dimethylformamide are added 5.5 g of potassium carbonate and 6 g of ethyl 4-chlorobutyrate, and the mixture is stirred at 60° C. for 21 hours. The reaction mixture is poured into water and extracted with ethyl acetate. The extract is washed with water, dried and concentrated. To a solution of the residue in 100 ml of 80 % methanol is added 3 g of potassium hydroxide, and the mixture is stirred at room temperature for two hours. After completion of the reaction, the methanol is distilled off under reduced pressure and the residue is dissolved into water and the aqueous solution is acidified with dilute hydrochloric acid. The precipitated crystals are collected by filtration and then recrystallizing from ethanol to give 8.3 g of 4-[3-(3,5-di-tertiary butyl-4-hydroxyphenyl)-1H-pyrazolo[3,4-b]pyridin-1-yl]butyric acid as pale yellow crystals, melting at 192°-194° C.

Provenance & Evidence