General steps:
1. For the solid disulfide (1,2-bis(4-bromophenyl)disulfide)
a. To a 10 mL Schlenk tube fitted with a magnetic stirrer, sequentially add 4-nitroaniline (0.2 mmol) and 1,2-bis(4-bromophenyl)disulfide (0.2 mmol).
b. Evacuate the reaction tube and backfill with dry nitrogen, repeat this procedure three times to ensure an oxygen-free environment.
c. Using a syringe, add acetonitrile (1 mL) followed by L-ascorbic acid (0.5 eq., 20 mg) dissolved in 0.1 mL of DMSO.
2. for liquid disulfide:
a. 4-nitroaniline (0.2 mmol) was added to a 10 mL Schlenk tube equipped with a magnetic stirrer.
b. Evacuate the reaction tube and backfill with dry nitrogen, repeating this procedure three times to ensure an oxygen-free environment.
c. Using a syringe, add acetonitrile (1 mL) followed by disulfide (0.2 mmol or 0.4 mmol) and L-ascorbic acid (0.5 equiv., 20 mg) dissolved in 0.1 mL of DMSO. 3.
3. The reaction mixture was stirred vigorously for 1 min before t-BuONO (0.3 mmol, 36 μL) was added via syringe.
4. The resulting mixture was stirred at 20 °C for 4 hours.
5. After completion of the reaction, the solvent was removed under reduced pressure.
6. The crude product was purified by column chromatography to afford the target product (4-bromophenyl)(4-nitrophenyl) sulfide.