Influence of para substituents on the rate of cyclization of 5-anilino-N-phenyl-2,4-pentadienylidenimine

Reactive polythiophenes with zincke salt structure: Synthesis, polymer reactions, and chemical properties

“…It is well known that N ‐(2,4‐dinitrophenyl)pyridinium chlorides, the so‐called Zincke salts, react with primary amines to yield N ‐substituted pyridinium compounds 41–49. Recently, we reported the synthesis of various Zincke salts, and some of them were used as starting materials for the synthesis of functional aromatic compounds and π‐conjugated polymers 50–58.…”

“…It is well known that N-(2,4-dinitrophenyl)pyridinium chlorides, the so-called Zincke salts, react with primary amines to yield N-substituted pyridinium compounds. [41][42][43][44][45][46][47][48][49] Recently, we reported the synthesis of various Zincke salts, and some of them were used as starting materials for the synthesis of functional aromatic compounds and p-conjugated polymers. [50][51][52][53][54][55][56][57][58] Based on these reports, PRThs (R ¼ Py þ DNP(Cl À ), where Py þ ¼ pyridinium, and DNP ¼ 2,4-dinitrophenyl) with a reactive N-(2,4-dinitrophenyl)pyridinium chloride unit bonded to the Th ring are promising materials as reactive PRThs.…”

Photochromic behavior of several new synthesized dyes via Zincke salts

“…A synthesis sequence for the preparation of 3 and 4 was not previously reported. However, a similar type of mechanism, as depicted for the preparation of 2, was established early [28][29][30] Z-isomer 2Z upon absorption of light rapidly isomerizes to the more stable thermodynamic E-isomer 2E together with the generation of an electrical pulse corresponding to a large cage in the molecular dipole moment upon photoexcitation.…”

Quaternary Pyridinium Compounds

“…The mechanism of the ring closure of azatrienes III-106 to give pyridinium ions, a reaction discovered many years ago by Zincke (lOl), has now been investigated further (102)(103)(104). From a series of careful kinetic studies Marvel and co-workers concluded that the data are in accord with the rate-determining step being an electrocyclization of 111-106 to the intenediate UI-107.…”