Hydrochloric Acid → HCID 178499535, compound

Participants

Reaction Steps

2,2,2-Trifluoroethanimidamide (6.7 g, 50. mmol, Oakwood) was dissolved in 0.5 M sodium methoxide in methanol (120 mL, 60. mmol) and 3-oxo-pentanedioic acid dimethyl ester (8.4 mL, 55 mmol, Aldrich) was added. The reaction solution was stirred at room temperature for 72 hours, followed by heating to 50° C. for 42 hours. The solvent was removed in vacuo. 1N HCl (50 mL) was added, this resulted in pH 5. After stirring overnight, 4M HCl (10 mL) and ethyl acetate were added, and layers separated. The aqueous layer was extracted with ethyl acetate. The combined organic extract was washed with brine, dried over sodium sulfate, filtered and concentrated. Flash chromatography, on 120 g silica gel cartridge, eluting with a gradient (solvent A=hexane; solvent B=3% iPrOH/EtOAc) from 0-30% solvent B in A over 40 minutes and hold at 30% for 20 minutes at a flow rate of 60 mL/min. The residue obtained on evaporation of product-containing fractions was mixed with DCM and the resulting white ppt (impurity) was removed by filtration. The filtrate was evaporated and the resulting residue was repurified (A=hexane; solvent B=iPrOH) on a 120 g silica gel cartridge, eluting with a gradient from 0-20% B in A over 25 minutes and hold at 20% B at a flow rate of 60 mL/min. Evaporated to afford an oil which crystallized on standing (5.2 g, 75% pure). A portion of the material was purified via preparative HPLC-MS (C18, eluting with a gradient of MeCN/H2O containing 0.1% TFA) to afford product used in the subsequent step. 1H NMR (300 MHz, CDCl3) δ 6.76 (s, 1H), 3.76 (s, 3H), 3.75 (s, 2H).

Provenance & Evidence