METHYL 2,3,4-TRIFLUOROBENZOATE synthesis

Yield:773873-68-0 81%

Reaction Conditions:

with thionyl chloride at 65; for 72 h;Inert atmosphere;Cooling with ice;

Steps:

4.2.3. General procedure for esterifications

General procedure: A solution of 2,4,6-trifluorobenzoic acid (47) or 2,3,4-trifluorobenzoic acid (48) (0.3 g, 1.7 mmol) in dry methanol (10 mL) was prepared in a three-necked, round-bottom flask fitted with a reflux condenser and a calcium chloride tube. The flask was placed in an ice/water bath, thionyl chloride (1.4 mL) was then added dropwise, and the mixture was heated at 60-65 °C for three days under argon. After removal of solvent, the resulting residue was purified by extraction with pentane in the case of 49 and using column chromatography on silica gel (hexane/diethyl ether 6:1) for 50.Methyl 2,4,6-trifluorobenzoate (49): Colorless oil, yield 85% (lit. [41] N. Punja, Eur. Pat. Appl. (1981) EP 31199 19810701, CAS Registry number 79538-28-6.[41] Bp 105-110 °C/15 mmHg). ¹H NMR (CDCl₃) δ 3.94 (s, 3H, OCH₃), 6.72 (dd, ³J = ³J = 8.3, 2H, H3 and H5).Methyl 2,3,4-trifluorobenzoate (50): Colorless oil, yield 81%. ¹H NMR (CDCl₃) δ 3.95 (s, 3H, OCH₃), 7.03 (m, 1H, H6), 7.74 (m, 1H, H5).

References:

Claramunt, Rosa M.;López, Concepción;López, Ana;Pérez-Medina, Carlos;Pérez-Torralba, Marta;Alkorta, Ibon;Elguero, José;Escames, Germaine;Acu?a-Castroviejo, Darío [European Journal of Medicinal Chemistry,2011,vol. 46,# 4,p. 1439 - 1447] Location in patent:experimental part