sulfuric acid; toluene-4-sulfonic acid in methanol T=0 - 5°C; ceramic diaphragm, carbon-rod anode, platinum cathode, 4.5 F/mol, 0.1A, cathode potential -1.45 to -1.65V vs. SCE;

(NH4)2S2O8; Montmorillonite K10; silver nitrate in hexane T=50°C; 2.5 h;

2,4,6-trichloro-1,3,5-triazine; zinc(II) chloride in acetonitrile Beckmann rearrangement; 2 h; Heating;

TEA in tetrahydrofuran T=0°C;