thiophene derivatives thiophene 110-02-1 2-thiophene carboxaldehyde 98-03-3 3-thiophene carboxaldehyde 498-62-4 2-thiophene carbonyl chloride 5271-67-0 3-thiophene carbonyl chloride 41507-35-1 2-thiophene carboxylic acid 527-72-0 3-thiophene carboxylic acid 88-13-1 3-methyl thiophene 616-44-4 2-bromothiophene 1003-09-4 3-bromothiophene 872-31-1 2,5-dibromothiophene 3141-27-3 3,4-dibromothiophene 3141-26-2 2-acetyl thiophene 88-15-3 2-thiophene acetic acid 1918-77-0 2-thienyl glyoxylic acid 4075-59-6 2-thiophene acetyl chloride 39098-97-0 2-thiophene ethanol 5402-55-1 2-thiophene ethyl amine 30433-91-1