Potassium Hydroxide → 3-(1-(Isopropylamino)phthalazin-6-yl)-4-methylbenzoic acid

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Reaction Steps

A stirred solution of ethyl 3-(1-(isopropylamino)phthalazin-6-yl)-4-methylbenzoate (4 g, 11 mmol) (obtained by method D below) in ethanol/water (4:1) (50 mL) at RT was treated with potassium hydroxide (1 g, 23 mmol). The mixture was warmed to reflux and stirred for 2 h (M+1=322). The mixture was cooled to RT, then concentrated to remove the organic solvent. The mixture was diluted with 1 N aq. sodium hydroxide (20 mL), extracted with ether (2×50 mL). The combined ether extract was washed with 1N aq. sodium hydroxide (20 mL). The combined water layer was neutralized to pH 7 with conc. HCl. The white precipitate was collected and washed with water (20 mL), azotropically dried with toluene and placed under high vacuum to give 3-(1-(isopropylamino)phthalazin-6-yl)-4-methylbenzoic acid as pale yellow solid.

Provenance & Evidence