The proposed oxidation mechanism of phenothiazine derivate containing thioether (S) to form sulfoxide (SO) -is described below in Scheme 5. During this study, the oxidation process occurred at the anode while the reduction process occurred at the cathode to maintain the balance of the oxidation reaction. The formation of phenothiazine sulfoxide resulted from an electrochemical reaction, where the drug underwent oxidation (loss of one electron) and formed a radical cation (step 2). The electrosynthesis reaction was carried out in a non-anhydrous MeCN solvent. During this step, water is reduced to produce hydrogen gas and hydroxide ions. The presence of hydrogen gas can be observed as bubble formation at the top of the electrochemical vial. The hydroxide ions present in the solution can attack the radical species, leading to the formation of an intermediate species in step 3. The intermediate can undergo rearrangement reactions where atoms within the molecule are reorganized to form new functional groups. This process can lead to the formation of CPZ-SO (step 4). The CPZ-SO molecule undergoes resonance in (step 5). In the case of CPZ-SO2, forming a sulfone would require further oxidation of the sulfoxide functional group and typically involves the addition of hydroxide ions to the sulfur atom (step 6). CPZ-sulfone is generally more stable than sulfoxide due to the presence of two oxygen atoms bonded to the sulfur atom (step 7).