1 STC 3-[(4-chloroanilino)sulfonyl]thiophene-2-carboxylic acid 1.000 2 NST 3-{[(3-nitroaniline]sulfonyl}thiophene-2-carboxylic acid 0.818 3 HTC 3-{[(4-carboxy-2-hydroxyaniline]sulfonyl}thiophene-2-carboxylic acid 0.783 4 NZ9 3-(cyclopropylsulfamoyl)thiophene-2-carboxylic acid 0.700