Hydrochloric Acid → 2-Cyano-4,5-diethoxy-3-fluorobenzyl methanesulfonate

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Reaction Conditions

Reaction Steps

3,4-Diethoxy-2-fluoro-6-(hydroxymethyl)benzonitrile (1 g, 4.18 mmol) was dissolved in 1,2-dimethoxyethane (10 mL), and cooled in a constant temperature bath at 8° C. after addition of methanesulfonyl chloride (0.39 mL, 5.02 mmol). Triethylamine (0.76 mL, 5.43 mmol) was added dropwise to this solution at approximately 20° C. or less. After stirring at the same temperature for 1 hour, toluene (5 mL) and 0.5 N hydrochloric acid (2 mL) were added, and this was transferred to a separatory funnel and toluene (5 mL) was used for rinsing. After separation of the solution, sequential washing was carried out with water (4 mL), 10% aqueous sodium hydrogen carbonate solution (4 mL), 10% brine (4 mL), and water (4mL). After the organic layer was evaporated, toluene (4 mL) was added, and water was removed by azeotropic distillation. Toluene (4 mL) was added to the residue and this was used in the next step. HPLC analytical values for the toluene solution: 99.10% (toluene peak is disregarded).

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