Hydrochloric Acid → 6-Sulfanyl-2H-1,4-benzoxazin-3(4H)-one

Participants

Reaction Steps

To a solution of 3-oxo-3,4-dihydro-2H-benzo[b][1,4]oxazine-6-sulfonyl chloride (5.8 g, 20.2 mmol), was added the hydrogen chloride in 1,4-dioxane (30 mL) followed by tin powder (12 g, 10.1 mmol). The resulting mixture was heated under reflux for 2 hours. After this time, the solvent of the reaction mixture was removed under vacuum to give the crude residue. The resulting residue was treated with ethyl acetate and washed with brine and water. The organic layer was separated, dried (Na2SO4) and concentrated. The crude material was purified by silica gel chromatography using a 60:40 mixture of hexane and ethyl acetate as eluent to afford the title product as a white solid (0.59 g, 16% yield). 1H NMR (400 MHz, d6-DMSO) δ: 10.82 (1H, s), 6.86 (2H, m), 6.81 (1H, m), 5.40 (1H, s), 4.53 (2H, s).

Provenance & Evidence