A trinitro compound, 1, 3,5 tris-(4-nitrophenyl) benzene, on complete reaction with an excess of $Fe/HCl$ gives major product, which on treatment with an excess of $NaN{O}_2/HCl$ at $0^{\circ }C$ provides P as the product. P, upon treatment with excess of $H_{2}O$ at room temperature, gives the product Q. Bromination of Q in aqueous medium then treatment with $Zn/\Delta$ furnishes the product R. The compound P upon treatment with an excess of aniline under mild acidic conditions gives the product S.