Acetonitrile → HCID 86650587, compound

Temperature

80 °C

To a solution of diethyl(ethoxymethylidene)propanedioate (3.52 g, 16.3 mmol) in ethanol (35 mL) were added benzyl hydrazinoacetate hydrochloride (3.20 g, 14.8 mmol), triethylamine (2.20 ml, 16.3 mmol) and acetonitrile (15 mL), and the mixture was stirred at 80° C. for 5 hr. The reaction mixture was diluted with diluted aqueous sodium hydrogen carbonate solution, extracted with ethyl acetate, dried over sodium sulfate, and concentrated under reduced pressure. The residue was purified by column chromatography (carrier: silica gel, eluent: hexane-ethyl acetate) to give ethyl [5-ethoxy-4-(ethoxycarbonyl)-1H-pyrazol-1-yl]acetate (0.56 g, 14%) wherein benzyl ester was converted to ethyl ester. To a solution of the present compound (0.56 g, 2.07 mmol) in tetrahydrofuran (10 mL) was added 1N aqueous sodium hydroxide solution (2.07 mL, 2.07 mmol) under ice-cooling, and the mixture was stirred at the same temperature for 1 hr. The reaction mixture was extracted with water, and washed with ether. The aqueous layer was neutralized with 1N hydrochloric acid (2 mL), and the mixture was extracted with ethyl acetate, washed with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was recrystallized from ethyl acetate-hexane to give the title compound (401 mg, 80%) as colorless crystals.

1. extractionextracted with ethyl acetate
2. dry with materialdried over sodium sulfate
3. concentrationconcentrated under reduced pressure
4. customThe residue was purified by column chromatography (carrier: silica gel, eluent: hexane-ethyl acetate)

ORD record

ord-f6635945875043e7ab574545d1278ffa

Source dataset

uspto-grants-2013_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08461348B2