Substituted 1‐[(phosphiny1)methyll‐2,4‐ and ‐2,6‐dinitrobenzenes, 1‐[(phosphinyl) methyl]‐2,4‐ and ‐2,6‐diaminobenzenes: New starting materials for preparation of fire‐resistant polymers

The nitration of the substituted [(phosphinyl)methyl]benzenes by fuming nitric and sulfuric acid gave the substituted l‐[(phosphinyl)methy1]‐2,4‐ and ‐2,6‐dinitrobenzenes (1). The formation of the two dinitro isomers was demonstrated by proton nuclear magnetic ('H‐NMR) and infrared (IR) spectroscopy. The nitration of [di(isopropoxy)phosphinylmethyl]benzene gave mainly the p‐nitro derivative due to steric hindrance. The phosphinyl ester groups of 1 were hydrolyzed by acids. The substituted l‐[(phosphinyl)methyl]‐2,4‐ and ‐2,6‐diaminobenzenes (2) were synthesized by catalytic hydrogenation of 1. In addition, the corresponding di(benzoy1amino) derivatives of 2 were prepared. Some of the synthesized compounds were investigated by gas chromatography‐mass spectroscopy (GC‐MS). Compounds 2 can be used as starting materials for preparation of phosphorus‐containing polymers such as polyamides, polyimides, polyureas, and bismaleimides and as curing agents for epoxy resins.