Boron tribromide → HCID 58934965, compound

Participants

Reaction Steps

To the solution of ethyl 7-methoxyl-6-methyl-2-(trifluoromethyl)-2H-chromene-3-carboxylate (5.2 g, 16.4 mmol) in 30 mL of dry dichloromethane at −78° C. in a dry ice/acetone bath was added a solution of 1.0 M of boron tribromide (164 mL, 164 mmol) dropwise. After finishing adding, the dry ice/acetone bath was removed. The reaction was stirred at room temperature overnight. The reaction was then cooled to −78° C. in dry ice/acetone bath. 200 mL of ethanol was added dropwise. After finishing addition, the cooling bath was removed. The reaction was allowed to warm to room temperature. LC-MS indicated that the reaction was finished. The volatiles were removed on rotavapor. The residue was then purified on silica gel column with 1:9 EtOAc/hexane. The desired product was isolated as off-white solid, 3.2 g. m.p.=151.0-153.0° C. 1H NMR (CDCl3/CD3OD/300 MHZ):7.68(s, 1H), 6.97(s, 1H), 6.43(s, 1H), 5.65(q, J=7.2 Hz, 1H), 4.31(m, 2H), 2.17(s, 3H), 1.36(t, J=6.9 Hz, 3H). 19F NMR(CDCl3/CD3OD/300 MHz) −79.03(d, J=7.3 Hz). 13C(CDCl3/CD3OD/300 Mhz) 164.8, 159.4,153.3, 137.8, 131.8, 123.9(q, J=287.9 Hz), 119.4, 112.5, 111.8, 102.6, 70.9(q, J=32.9 Hz), 61.4, 15.3, 14.4. LC-MS(ES+): 303.1(M+1). MS(EI+): 302.0(M+, 80), 233(M−69, 100); High resolution MS: m/z calc. For C14H13F3O4: 302.0766(M+, theoretical), found: 302.0763.

Provenance & Evidence