Lithium hydroxide, monohydrate → HCID 9935937, compound

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Reaction Steps

The solution of 4-(3,5-dimethoxy-phenyl)-2-(2-trifluoromethyl-phenyl)-1,1-dioxo-1,2-dihydro-1λ6-benzo[e][1,2]thiazine-3-carboxylic acid methyl ester (1.29 g, 2.5 mmol) and lithium hydroxide monohydrate (0.3 g 12.5 mmol) in 30 mL of MeOH and 15 mL water was refluxed for 2.5 hours and evaporated to an oil. The residue was dissolved in water, washed with ethyl ether, and the aqueous layer decanted. The aqueous layer was acidified to pH 1 with concentrated HCl and extracted into ethyl ether, washed with brine, dried over anhydrous magnesium sulfate, filtered, and evaporated to a foam. The residue was chromatographed on 50 g silica gel eluted with chloroform, and the appropriate fractions were concentrated in vacuo and evaporated from ethyl ether giving a solid foam, 1.4 g, 66% yield. NMR spectra and elemental analysis were consistent with the structure.

Provenance & Evidence