3-Bromoacetyl-2-thiophenesulfonamide synthesis

Yield:154127-28-3 72%

Reaction Conditions:

Stage #1: 3-Acetylthiophene-2-sulfonamidewith toluene-4-sulfonic acid in acetonitrile at 20; for 0.5 h;
Stage #2: with N-Bromosuccinimide in acetonitrile; for 2 h;Heating / reflux;

Steps:

1.D

Step D: 3-bromoacetyl-2-thiophenesulfonamide (VI); The product from step C (91 g, 0.44 moles) was suspended in acetonitrile (2000 ml) and cooled to 20°C. p-toluenesulfonic acid (114.5 g, 0.66moles) was added to the reaction mass at 20⁰C. The reaction mixture was stirred at ambient temperature for 0.5 hours. N- bromosuccinimide (78 g, 0.44 moles) was slowly added to reaction mixture. The reaction mass was refluxed for 2 hours. The volatiles were evaporated and the residue was mixed with cold water. The precipitate was filtered, washed with the cold water and hexane, dried in air to get the compound of the formula VI (91 g, 72 %).

References:

WO2008/62463,2008,A2 Location in patent:Page/Page column 24