HCID 72942111, compound → HCID 72217216, compound

Participants

Reaction Conditions

Reaction Steps

A 1:2.5 mixture of (6-chloro-3-trifluoromethyl-pyridin-2-yl)-acetic acid tert-butyl ester and (6-chloro-5-trifluoromethyl-pyridin-2-yl)-acetic acid tert-butyl ester (semi-crude; 10.15 g, 34.33 mmol) is dissolved in EtOH (100 ml) previously saturated at 0° C. with HCl gas. The solution is heated to 90° C. After 30 minutes at 90° C., TLC analysis indicates full conversion of the starting material. The solvent is completely evaporated. The crude reaction product is dissolved in EtOAc, washed once with conc. aqueous NaHCO3 and once with H2O (backextracted with EtOAc). The organic layer is dried over Na2SO4 and concentrated. Careful purification by FCC (hexanes/EtOAc 100:0, 97:3, 95:5, 9:1, 85:15, 8:2 to 7:3) separates the two regioisomeric compounds, (6-chloro-3-trifluoromethyl-pyridin-2-yl)-acetic acid tert-butyl ester and (6-chloro-5-trifluoromethyl-pyridin-2-yl)-acetic acid ethyl ester. Analytical data for (6-Chloro-3-trifluoromethyl-pyridin-2-yl)-acetic acid ethyl ester: 1H NMR (CDCl3, 400 MHz) δ 1.28 (t, J=6.7 Hz, 3H), 3.95 (s, 2H), 4.12 (q, J=6.7 Hz, 2H), 7.32 (d, J=8.9 Hz, 1H), 7.85 (d, J=8.9 Hz, 1H); ES-MS: 268.2 [M+H]+.

Provenance & Evidence