Lawesson's reagent → HCID 86727311, compound

Participants

Reaction Steps

A solution of 2-(7-methyl-6-nitro-3-oxo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-propionic acid ethyl ester (0.5 g crude, 48% pure, 0.81 mmol) and Lawesson's reagent (0.656 g, 1.62 mmol) in toluene (30 mL) was heated at 120° C. for 20 h. The reaction mixture was cooled to ambient temperature and the solvent was removed in vacuo to give the crude product, which was purified by chromatography on silica gel (eluting with 20% EtOAc in petroleum ether) and further purified by preparative TLC (eluting with 20% EtOAc in petroleum ether) to give 2-(7-methyl-6-nitro-3-thioxo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-propionic acid ethyl ester (0.130 g, 50%) as a solid. 1H NMR (CDCl3, 400 MHz): δ 7.64 (s, 1H), 6.90 (s, 1H), 6.61 (s, 1H), 4.90 (q, J=15.6 Hz, 2H), 4.20 (q, J=7.2 Hz, 2H), 2.54 (s, 3H), 1.65 (d, J=7.2 Hz, 3H), 1.21 (t, J=7.2 Hz, 3H).

Provenance & Evidence