Dichloromethane → 6-Chloro-7-(4-(4-chloro-2-hydroxyphenethylcarbamoyl)phenoxy)chroman-4-carboxylic acid

Participants

Reaction Steps

To a stirred, chilled (0° C.) solution of boron trichloride in dichloromethane (13.6 mL; 1.0 M; 7 eq.) was added, portionwise over 2 minutes, solid 6-chloro-7-(4-(4-chloro-2-methoxyphenethylcarbamoyl)phenoxy)chroman-4-carboxylic acid (1.0 g; 1.94 mmol) under nitrogen atmosphere. The resulting mixture was allowed to warm to ambient temperature, stirred for 8 hours and then heated to 35° C. for 24 hours. The reaction was quenched with 5 mL water (significant effervescence observed while adding first 2 mL) and then 6 mL of saturated Na2CO3 was added to bring the pH to 4. During the last 1 mL of addition, significant amounts of precipitates formed in the lower organic layer. The warm bath was removed and replaced with an ice bath. The material was stirred for 5 minutes in ice bath, then solids collected on a medium frit, washing once with 5 mL chilled MTBE. This material was purified via Biotage chromatography with methanol in ethyl acetate to provide the desired 6-chloro-7-(4-(4-chloro-2-hydroxyphenethylcarbamoyl)phenoxy)chroman-4-carboxylic acid (195 mg). MS (apci, neg) m/z=500. 1H NMR (400 MHz, D6 DMSO) δ 8.45 (t, 1H), 7.82, (d, 2H), 7.46 (s, 1H), 7.06 (d, 1H), 6.95 (d, 2H), 6.83 (d, 1H), 6.75 (dd, 1H), 6.60 (s, 1H), 4.22 (m, 1H), 4.12 (t, 1H), 3.72 (br s, 1H), 3.60 (t, 1H), 2.76 (t, 2H), 2.22 (m, 1H), 1.99 (m, 1H), 1.76 (m, 1H).

Provenance & Evidence