Highly Efficient and Practical Method for Synthesis of 2,2′-Azino-Bis(3-Ethyl-benzothiazoline-6-Sulfonic Acid) (ABTS) and Its Diammonium Salt

A highly efficient and practical protocol for synthesis of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and its diammonium salt has been carried out by six steps. On comparison of the traditional methods, the present protocol has many advantages including mild reaction conditions, excellent product yields, shorter reaction steps, and no hazardous reagents. Moreover, the present protocol also provides an easy scaling and separation method.