Phosphorus sulfide (P2S5) → [2-(4-Bromo-2-fluoro-benzylthiocarbamoyl)-5-fluoro-4-methyl-phenoxy]-acetic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

A stirring solution of [2-(4-bromo-2-fluoro-benzylcarbamoyl)-5-fluoro-4-methyl-phenoxy]-acetic acid ethyl ester (0.816 g, 1.83 mmol) in pyridine (3.7 mL, 0.5 M) was treated with phosphorus pentasulfide (0.41 g, 0.92 mmol) and heated to 115° C. for 3 h. The reaction was allowed to cool to room temperature, diluted with ethyl acetate and successively washed with 1 M HCl and saturated aq NaCl. The organic layer was dried over Na2SO4, filtered, and concentrated under reduced pressure. The resulting brown oil was dissolved in a minimal amount of methylene chloride and flushed through a plug of silica using 40% ethyl acetate in heptane as the eluant. The filtrate was concentrated to afford [2-(4-bromo-2-fluoro-benzylthiocarbamoyl)-5-fluoro-4-methyl-phenoxy]-acetic acid ethyl ester (0.75 g, 89%) as a yellow solid: mp 98–100° C.; Rf 0.45 (30% ethyl acetate in heptane); 1H NMR (CDCl3, 300 mHz) δ 10.15 (bs, 1H), 8.26 (d, J=8.4 Hz, 1 H), 7.38 (t, J=8.4 Hz, 1 H), 7.26–7.23 (m, 2 H), 6.53 (d, J=10.8 Hz, 1 H), 5.08 (d, J=5.4 Hz, 2 H), 4.67 (s, 3 H), 4.20 (q, J=7.2 Hz, 2 H), 2.23 (s, 2 H), 1.27 (dt, J1=6.8 Hz, J2=0.6 Hz, 3 H).

Provenance & Evidence