Five and four tenth grams of the monoamino compound were dissolved in hot conc. HCl, cooled in ice, and diazotized with sodium nitrite solution, until starch iodide paper showed excess nitrous acid. The diazotization was performed in ice, with mechanical stirring, and required about an hour. The diazo solution was poured into a solution of 3 grams B-naphthol in 8 grams of NaOH and 60 cc. of water, while gradually stirring. A very deep red solution formed. This was acidified with excess HCl, salted out by NaCl, and crystallized from aniline-alcohol mixture. In the pure state, it is a deep red powder, with a metallic lustre when rubbed, melting at 284.2°C. An analysis showed the following result, Calculated for C₂₃H₁₅N₃OSe Found Nitrogen 9.81% 9.75% Dinitro Derivative The nitration for the production of dinitro derivative was at first carried out under the same conditions as in the preparation of mononitro compound and after the latter was formed more nitric acid mixture was added with the addition of heat: conc. sulphuric acid, keeping it below room temperature. It was then cooled in a freezing mixture and half the volume of a nitric acid mixture (prepared and cooled by mixing 19 grams of nitric and 30 grams of sulphuric acids) was introduced very slowly to the selenazole solution through a dropping funnel, maintaining at this temperature for two hours (using mechanical stirring). The remaining half of the nitric acid mixture was then slowly introduced and the flask was heated on a water-bath for two hours. The solution was poured into two liters of water, the precipitate filtered off, dried and recrystallized several times from acetic acid. The yield was 80 per cent. This dinitro compound crystallizes in fine yellow needles, m. p., 246.8°C. (corr.), very insoluble in water, but soluble in hot acetic acid, acetic anhydride, nitrobenzene, nitrotoluene, ethyl alcohol, and difficultly soluble cold. It was analyzed and the following results were found, Calculated for Found C₁₃H₇N₃O₄Se I II Nitrogen 12.07% 12.30% 12.12% Diamino Derivative The conversion of the dinitro to diamino derivative was accomplished in the same manner as the reduction of the mononitro derivative excepting that twice as much tin and HCl were used. This diamino compound crystallizes in yellowish glistening needles from alcohol and pyridine; m. p., 269°-270.5°C.; was analyzed and gave the following results, Calculated for Found C₁₃H₁₁N₃Se I II Nitrogen 14.6% 14.4 14.7 Diacetyl and Dibenzylidene Derivatives