Ammonium Chloride → 5-chloro-N-(2,4-dimethoxybenzyl)-2,4-difluoro-N-(1,3,4-thiadiazol-2-yl)benzenesulfonamide

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Reaction Conditions

Reaction Steps

N-(2,4-Dimethoxybenzyl)-1,3,4-thiadiazol-2-amine (Preparation 19, 203.4 g, 0.809 mol) was dissolved in 2-methyltetrahydrofuran (1.63 L) and the yellow suspension cooled to between −38° C. and −45° C. Lithium bis(trimethylsilyl)amide (890 mL of 1M solution in tetrahydrofuran, 0.890 mol) was added slowly over 15 minutes keeping the temperature between −38° C. and −45° C. to give an orange suspension. This orange suspension was stirred at −38° C. to −45° C. for 45 minutes and then a solution of 5-chloro-2,4-difluorobenzenesulfonyl chloride, (200 g, 0.809 mol) in 2-methyltetrahydrofuran (407 mL) added slowly over 20 minutes keeping the temperature between −38° C. and −45° C. The mixture was warmed to 15° C. over 1 hour. The reaction was quenched with a solution of ammonium chloride (203.4 g, 3.80 mol) in water (1.02 L) and stirred vigorously for 5 minutes. The layers were separated and the organic layer washed with water (813.6 mL) and concentrated in vacuo to give an orange solid which was triturated with isopropyl acetate (1.22 L) to afford the title compound as a yellow-orange solid (218.6 g, 58%).

Provenance & Evidence