Yield:183235-79-2 61%

Reaction Conditions:

with pyridine in dichloromethane at -20 - 20; for 21 h;

Steps:

P.2 (Cyclopropylamino)(oxo)acetic acid (P2)

Preparation P2
(Cyclopropylamino)(oxo)acetic acid (P2)
Ethyl chloro(oxo)acetate (96 mL, 0.86 mol) was added over 10 minutes to a -20° C. solution of cyclopropylamine (60 mL, 0.86 mol) and pyridine (70 mL, 0.86 mol) in dichloromethane (740 mL), and the reaction mixture was stirred at 0° C. for 1 hour, then at 20° C. for 20 hours.
The reaction mixture was washed with aqueous hydrochloric acid (1 M, 3*185 mL), then the organic layer was stirred with aqueous sodium hydroxide solution (1 M, 930 mL, 0.93 mol) for 30 minutes.
The resulting aqueous layer was acidified to pH 1 with concentrated hydrochloric acid (78 mL), treated with sodium chloride (100 g), and extracted with dichloromethane (6*500 mL) and ethyl acetate (6*500 mL).
The combined organic layers were dried over magnesium sulfate, filtered, and concentrated in vacuo; the resulting solid was mixed with ethyl acetate (150 mL) and warmed to reflux.
After cooling to room temperature over 16 hours with stirring, the solid was collected via filtration and washed with ethyl acetate, affording the product as a sparkling white solid. Yield: 67.8 g, 0.525 mol, 61%. LCMS m/z 130.0 [M+H]⁺. ¹H NMR (400 MHz, DMSO-d₆) δ 13.73 (br s, 1H), 8.83 (br d, J=4.0 Hz, 1H), 2.68-2.77 (m, 1H), 0.61-0.68 (m, 2H), 0.54-0.61 (m, 2H).

References:

US2014/235612,2014,A1 Location in patent:Paragraph 0193; 0194