1: 1.) Na2CO3, sulfanilic acid, NaNO2, 2.) 85percent aq. sodium hydrosulfite / 1.) water, a.) RT, overnight, b.) 40 deg C, 3 h, 2.) water, 60 deg C, 1 h 2: Et3N / toluene / 4 h / Heating View Scheme

triethylamine in toluene 4 h; Heating;