Lawesson's reagent → 6-(3-bromophenyl)-4,4-dimethyl-1,4-dihydro-2H-3,1-benzoxazine-2-thione

Participants

Reaction Conditions

Reaction Steps

A mixture of 6-(3-bromo-phenyl)-4,4-dimethyl-1,4-dihydro-benzo[d][1,3]oxazin-2-one (3 g, 9.04 mmol) and Lawesson's Reagent (1.83 g, 4.51 mmol) in toluene (30 mL) was heated to 110° C. for 24 hours. The reaction was cooled, the toluene removed in vacuo and the residue purified via flash chromatography (silica gel, 20% ethyl acetate/hexane) to give 6-(3-bromophenyl)-4,4-dimethyl-1,4-dihydro-2H-3,1-benzoxazine-2-thione (1.93 g, 61%) as a yellow solid: mp 191–193° C.; 1H-NMR (DMSO-d6) (12.3 (s, 1H), 7.92 (s, 1H), 7.72–7.65 (m, 3H), 7.57–7.54 (m, 1H); 7.45–7.39 (m, 1H), 7.14–7.11 (m, 1H), 1.7 (s, 6H); MS (ES) m/z 347 ([M−H]−, 100%); Anal. Calc. For C16H14BrNOS: C, 55.18, H, 4.05, N, 4.02 Found: C, 55.17, H, 3.93, N, 3.97.

Provenance & Evidence