BIS- 2,4-DINITROPHENYL -METHYL-PYRIDINIUM COMPOUNDS

摘要

Bis-(2,4-dinitrophenyl)-methylpyridinium compounds useful as a pH indicator or for the detection of ammonia having the formula: IMAGE wherein one of R1 and R2 is a bis-(2,4-dinitrophenyl)-methyl radical and the other is a lower alkyl radical; R2 can also be hydrogen atom or trifluoromethyl; R3 and R4 are hydrogen or, together with the carbon atoms to which they are attached, represent a benzene ring; and X(-) is an appropriate acid anion or said compounds are betaines.