2-AMINO-OXAZOLE-5-CARBOXYLIC ACID ETHYL ESTER

Ethyl 2-chloro-3-oxopropanoate (13) 4.48 g (29.8 mmol, 1.00 mol eq) and 1.79 g (29.8 mmol, 1.00 mol eq) of urea were mixed with 40 mL water. The reaction mixture was stirred at 100 °C for 1 h. A final pale yellow suspension was cooled down to RT, neutralized by a saturated aq. solution of NaHCOA mixture of 1.19 g (8.8 mmol, 1.50 mol eq) of CuCl2 abs and 1.05 mL (8.8 mmol, 1.50 mol eq) of tBuONO in 30 mL of AN abs under Ar was heated to 60 C. By this temperature 920.0 mg (5.9 mmol, 1.00 mol eq) of Ethyl 2-chloro-3-oxopropanoate (13) 4.48 g (29.8 mmol, 1.00 mol eq) and 1.79 g (29.8 mmol, 1.00 mol eq) of urea were mixed with 40 mL water. The reaction mixture was stirred at 100 C for 1 h. A final pale yellow suspension was cooled down to RT, neutralized by a saturated aq. solution of NaHCO3 and extracted with EA (3 x 50 mL). The combined organic layers were dried using Na2SO4, filtered and concentrated under reduced pressure. The crude product was purified using FLC (SiO2, H / EA = 1 / 2) yielding 2.40 g (15.4 mmol, 51.3 %) of According to Reference Example 2-1, Using To a mixture of Step 1: ethyl 2-[(4-bromopyridin-2-yl)amino]-1, 3-oxazole-5-carboxylate To a mixture of To a solution of To the suspension of the oxazole ethyl ester (3.13 g, 20.0 mmol) in water, 1 M NaOH (0.04 mL, 40.0 mmol) was added. The mixture was stirred at room temperature for 3 h, and afterward adjusted to pH 2-3 with 1 M HCl. The resulting precipitate 1 was filtered, washed with diethyl ether and dried overnight at 60 C. Yield: 93%;white crystals, mp 210-212 C. 1H NMR (400 MHz, DMSO-d6): 7.01(s, 2H, NH2), 7.13 (s. 1H, Ar-H), 12.11 (br s, 1H, COOH) ppm. HRMS(ESI): m/z [M H] calcd for C4H5N2O3 129.1347; found 129.1537.

Molecular Weight:156.14
XLogP3:0.5
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:5
Rotatable Bond Count:3
Exact Mass:156.05349212
Monoisotopic Mass:156.05349212
Topological Polar Surface Area:78.4
Heavy Atom Count:11
Complexity:151
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes