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N-Aminoarylpyridinium salts react with nitrosyl perchlorate to give diazonium dications, which undergo diazo coupling, exchange a diazo group, and are cyclized by the Pschorr method.

Isochromylium cations containing easily detached groupings (NHCOR, NH2, OCH3) in the 3 position react readily with o-phenylenediamine. The reaction is accompanied by opening of the benzopyrylium ring and condensation of the resulting compound at one or two amino groups of o-phenylenediamine. Benzimidazo[3,2-b]isoquinolinium salts were synthesized alternatively by acylation of 2-(3,4-dimethoxybenzyl)benzimidazole. The tautomerism of the synthesized N-(2-aminoaryl)isoquinolinium perchlorates was investigated.

The pyridinium ring as a substituent in aniline is an electron acceptor, the effect of which is comparable to the effect of NO2 and N(CH3)2 groups. Correlation of the reactivities with the basicities of the amino groups is not observed in the investigated reactions of N-(aminophenyl)pyridinium perchlorates with some electrophilic reagents, inasmuch as steric factors apparently play a greater role.

Nitro and amino derivatives of pyrido[1,2-f]phenanthridinium perchlorate were synthesized by the Pschorr method and by photocyclodehydrogenation from N-(nitrophenyl)-or N-(aminophenyl)pyridinium perchlorates. The mechanism of the photoconversion was investigated.

The electronic spectra of a number of benzylidene derivatives of N-aminoarylpyridinium perchlorates are associated with absorption localized on the individual pyridinium and azomethine fragments and with intramolecular charge transfer (ICT) from the azomethine fragment to the pyridinium ring. The luminescence is associated with the latter process. The photochromism is due to proton transfer in the excited state of the azomethine fragment, which competes with ICT, and is also due to structural factors.

Isochromylium cations containing easily detached groupings (NHCOR, NH2, OCH3) in the 3 position react readily with o-phenylenediamine. The reaction is accompanied by opening of the benzopyrylium ring and condensation of the resulting compound at one or two amino groups of o-phenylenediamine. Benzimidazo[3,2-b]isoquinolinium salts were synthesized alternatively by acylation of 2-(3,4-dimethoxybenzyl)benzimidazole. The tautomerism of the synthesized N-(2-aminoaryl)isoquinolinium perchlorates was investigated.

Die aus Nitrophenylendiaminen (I) und Pyryliumsalzen (II) gebildeten Aminophenylpyridiniumsalze (III) bilden bei der Diazotierung die Diazoniumsalze (IV), aus denen durch Stickstoffabspaltung Pyridophenanthridiniumsalze (V) erhalten werden.