4,4'-diaminostilbene-2,2'-disulfonic acid in benzene 2 h; Ambient temperature;

1: 20 percent / LiN3 / ethanol / 2 h / Heating 2: 47 percent / DAST / benzene / 2 h / Ambient temperature View Scheme

1: 1.) pyridine / 1.) a) 0 deg C, overnight, b) 70 deg C, 3 h, 2.) a) 0 deg C, 1 h, b) RT, overnight 2: 95 percent / 1 N NaOH / ethanol / 3 h / 60 °C 3: 20 percent / LiN3 / ethanol / 2 h / Heating 4: 47 percent / DAST / benzene / 2 h / Ambient temperature View Scheme

1: 95 percent / 1 N NaOH / ethanol / 3 h / 60 °C 2: 20 percent / LiN3 / ethanol / 2 h / Heating 3: 47 percent / DAST / benzene / 2 h / Ambient temperature View Scheme

1: 1.) pyridine / 1.) a) 0 deg C, overnight, b) 70 deg C, 3 h, 2.) a) 0 deg C, 1 h, b) RT, overnight 2: 95 percent / 1 N NaOH / ethanol / 3 h / 60 °C 3: 20 percent / LiN3 / ethanol / 2 h / Heating 4: 47 percent / DAST / benzene / 2 h / Ambient temperature View Scheme

acetic acid 0.25 h; Heating;