N,N'-Dimethylethylenediamine → ethyl (R)-2-methanesulfonyl-4-(3-methyl-1,1-dioxo-1lambda6-isothiazolidin-2-yl)benzoate

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Reaction Steps

To a mixture of ethyl 4-bromo-2-methanesulfonylbenzoate (13.88 g), sodium iodide (13.54 g) and copper(I) iodide (4.30% g) were added toluene (46 mL) and N,N′-dimethylethylenediamine (4.86 mL), and the mixture was stirred with heating under reflux for 8 hr under a nitrogen stream. The reaction mixture was cooled, water was added, and the mixture was extracted with ethyl acetate. The solvent was evaporated from the organic layer, the obtained residue was purified by column chromatography (hexane:ethyl acetate) to give ethyl 4-iodo-2-methanesulfonylbenzoate (10.32 g). To a mixture of the obtained ethyl 4-iodo-2-methanesulfonylbenzoate (3.22 g), (R)-3-methylisothiazolidine 1,1-dioxide (1.23 g) described in Preparation Example 2, copper(I) iodide (4.30 g), N,N′-dimethylethylenediamine (0.92 mL) and potassium carbonate (2.52 g) was added toluene (9.2 mL), and the mixture was stirred with heating under reflux for 8 hr under a nitrogen stream. The reaction mixture was cooled, water was added, and the mixture was extracted with ethyl acetate. The solvent was evaporated from the organic layer, and the obtained residue was purified by column chromatography (hexane:ethyl acetate) to give the title compound (1.7 g).

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