8-Amino-10-ethyl-7-methylphenazin-2(10H)-one and sodium polysulphide in Copper sulfate monohydrate under the existence of in 190 ℃ calcination 15 hours. This is Pyridine by 2 – methyl – 5 – ethylamino – aniline and 4-Nitrosophenol in dilute hydrochloric acid of condensation, then use Manganese dioxide oxidation and have to. Add in the roasting Molybdic acid can make the color partial red (GP 590873).
