Diisopropylethylamine → HCID 71279164, compound

Participants

Reaction Conditions

Reaction Steps

To a suspension of 4-(ethoxycarbonyl)-1-methyl-1H-pyrazole-5-carboxylic acid (500 mg, 2.52 mmol, prepared as described in US 2011/0071128) in THF (12.5 mL) were added 2-(5-methyl-2-phenyloxazol-4-yl)ethanamine hydrochloride (602 mg, 2.52 mmol), 1-propanephosphonic acid cyclic anhydride (4.01 g, 3.75 mL, 6.31 mmol) and N,N-diisopropylethylamine (2.61 g, 3.53 mL, 20.2 mmol) at RT. The mixture was stirred at 70° C. for 2 h, poured into KHSO4 (10% aqueous solution, 50 mL) and extracted with ethyl acetate (2×75 mL). The organic phases were washed with water (50 mL) and brine (50 mL). The combined organic layer was dried over MgSO4 and concentrated in vacuo to give 735 mg crude product. The product was obtained after purification by flash chromatography (using silica gel and an ethyl acetate/heptane gradient) as white solid (410 mg, 1.07 mmol, 42.5%).

Provenance & Evidence