Hydrochloric Acid → 5-amino-3-(2-fluoro-5-nitrophenyl)-3,6,6-trimethyl-3,6-dihydro-2H-1,4-thiazine 1,1-dioxide

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Reaction Steps

A suspension of N-(1-((2-cyanopropan-2-yl)sulfonyl)-2-(2-fluoro-5-nitrophenyl)propan-2-yl)-2-methylpropane-2-sulfinamide (560 mg, 1.292 mmol) in MeOH (10 ml) was treated with hydrogen chloride (4M in 1,4-dioxane) (3.23 ml, 12.92 mmol) for 1 h at RT. The mixture was concentrated in the stream of nitrogen, redissolved in 10 ml EtOH and copper (I) chloride (134 mg, 1.356 mmol) was added. The mixture was sonicated for 5 min, and heated at reflux for 2 h. After concentrating in vacuo, the residue was partitioned between 10 ml DCM and 10 ml 2N NaOH solution. The organic layer was separated, washed with brine and concentrated to afford crude 5-amino-3-(2-fluoro-5-nitrophenyl)-3,6,6-trimethyl-3,6-dihydro-2H-1,4-thiazine 1,1-dioxide (420 mg, 1.275 mmol, 99% yield), which was used without further purification.

Provenance & Evidence