Dimethylformamide → 3-[1-[4-[2-[1-oxophthalazin-2(1H)-yl]ethoxy]benzyl]-3-phenyl-1H-pyrazol-4-yl]propionic acid

Participants

Reaction Conditions

Reaction Steps

A mixture of ethyl 3-[1-[4-(2-bromoethoxy)benzyl]-3-phenyl-1H-pyrazol-4-yl]propionate (1050 mg), 1(2H)-phthalazinone (530 mg), potassium carbonate (1000 mg) and N,N-dimethylformamide (15 ml) was stirred at 90° C. for 5 hours. The reaction mixture was poured into water, and extracted with ethyl acetate. The ethyl acetate layer was washed successively with dilute hydrochloric acid and saturated aqueous sodium chloride solution, dried (MgSO4) and concentrated. The residue was subjected to silica gel column chromatography to obtain a colorless oily substance from the fraction eluted with ethyl acetate-hexane (1:1, volume ratio). After a mixture of the resulting colorless oily substance, 1N aqueous sodium hydroxide solution (5 ml), tetrahydrofuran (5 ml) and ethanol (5 ml) was stirred at room temperature for 3 hours, 1N hydrochloric acid (5 ml) was added to the mixture, and then the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with a saturated aqueous sodium chloride solution, dried (MgSO4), and concentrated. The resulting colorless crystals were collected by filtration to obtain 3-[1-[4-[2-[1-oxophthalazin-2(1H)-yl]ethoxy]benzyl]-3-phenyl-1H-pyrazol-4-yl]propionic acid (1460 mg, yield 90%). This was recrystallized from acetone-hexane. Melting point: 155–156° C.

Provenance & Evidence