C.I. Solvent Orange 5 (by 3-Amino-2-hydroxy-5-nitrobenzenesulfonic acid diazotization, with 3-Methyl-1-phenyl-1H-pyrazol-5(4H)-one coupling and then in the 130 ℃ in Chromium formate in aqueous solution, heating 3 hours, make it into Chromium complex and) into metal complex.
