Polynitro aromatic compounds in analytical chemistry II: Reaction of menadione with 2,4-dinitrophenylhydrazine.

The intense blue color formed in the official assay of menadione injection by treatment of the sample with 2,4-dinitrophenylhydrazine and ammonia is shown by data from visible light spectra and mass spectra and by comparison of the pKa value with that of the corresponding reaction product of acetone to be due to proton abstraction from a monohydrazone.

Polynitro aromatic compounds in analytical chemistry I: reaction with ouabain and digitoxin.

By the use of NMR spectroscopy, the highly colored reaction products formed by ouabain or digitoxin in with 1,3,5-trinitrobenzene or 2,4,6-trinitroanisole in the presence of alkali (as used for the determination of these glycosides) are shown to be Meisenheimer complexes. The complexes are produced by attachment of a carbon of the butenolide ring to an aromatic carbon of the nitro compound with formation of a charge-delocalized cyclohexadienate anion.