4-Chlorophenyl Isocyanate → N-[[(4-chlorophenyl)amino]carbonyl]benzo[B]thiophene-2-sulfonamide

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Reaction Steps

To a solution of 13.4 g (100 mmol) of benzothiophene, dissolved in 50 mL anhydrous diethyl ether, was added 62.5 mL of a 1.6 M hexanes solution of n-butyllithium (100 mmol) The reaction mixture was refluxed for 4 hours and then cooled to about -20° C. Sulfuryl chloride (16.1 mL, 200 mmol) was added dropwise. This suspension was stirred at ambient temperature overnight and then added to 75 mL of ice water. The ether layer was dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was added to 100 mL of concentrated ammonium hydroxide and the suspension was warmed to 55° C. The solution was diluted with 200 mL of water and stirred at ambient temperature for several hours Product was collected by filtration under vacuum. The residue was suspended in 150 mL toluene and filtered to provide 9.2 g of 2-benzo[B]thiophenesulfonamide. The sulfonamide (25 mmol) was reacted with 4-chlorophenylisocyanate (27 mmol) as described in Method A above to obtain 8.7 g of the title product as a solid. 1H NMR (CD3SOCD3): δ9.12 (s, 1 H), 8.22 (s, 1 H), 8.10 (m, 2 H), 7.50 (m, 2 H), 7.44 (d, J =9 Hz, 2 H), 7.32 (d, J =9 Hz, 2 H).

Provenance & Evidence