Hydrochloric Acid → HCID 69360143, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of methyl 3-amino-5-(1,1-dioxidotetrahydro-2H-1,2-thiazin-2-yl)benzoate (D267) (7.5 g, 26.4 mol, 1 equiv) in a 2N aqueous HCl solution (75 ml) and MeOH (75 ml) at 0° C. was added NaNO2 (4.0 g, 58.1 mmol, 2.2 equiv) portionwise over 20 min. MeOH (50 ml) and H2O (200 ml) were added and the resulting mixture was stirred at 95° C. for 1 h then cooled to room temperature. Most of the MeOH was removed in vacuo and the resulting aqueous phase was extracted with AcOEt. The insoluble material was filtered off to give methyl 3-(1,1-dioxidotetrahydro-2H-1,2-thiazin-2-yl)-5-hydroxybenzoate (D) (0.63 g, 8%). The organic phase was washed with brine, dried over MgSO4 and concentrated in vacuo to give a brown residue which was redissolved in AcOEt. The organic phase was extracted with a saturated aqueous Na2CO3 solution and the aqueous phase was extracted three times with Et2O then acidified to pH 1 and re-extracted three times with AcOEt. The combined organic phases were washed with brine, dried over MgSO4 and concentrated in vacuo to give methyl 3-(1,1-dioxidotetrahydro-2H-1,2-thiazin-2-yl)-5-hydroxybenzoate (D268) (2.2 g, 30%).

Provenance & Evidence