Reactivity of 4-Methylpyridinium Salts in a New Reaction of Ring Transformation of Pyridine and Isoquinoline Derivatives

Abstract

Dependence of reactivity on substituents in the pyridine ring of the 4-methylpyridinium salts was studied in intermolecular reaction of ring transformation involving quaternary salts of pyridinium and isoquinolinium promoted by methylammonium sulfite.

Reactions of Zincke’s salts with 2,3-dimethylbenzothiazolium iodide

“…13 C NMR spectra were recorded on a Bruker DRX 500 spectrometer (125.76 MHz) in DMSO d 6 with its sig nal as the internal standard (δ 128.02). 13 C NMR spectra were recorded on a Bruker DRX 500 spectrometer (125.76 MHz) in DMSO d 6 with its sig nal as the internal standard (δ 128.02).…”

Advances in the synthesis of 4-aryl- and 4-hetarylpyridines

“…Starting from 1,4-dimethyl-2-phenylpyridinium iodide (158a) or 1,4,4 H -trimethyl-2,2 H -bipyridylium iodide (158b) and 1-methylpyridinium iodide 154 (R 1 = Me), 2,4-diphenylpyridine (159a) or 4-phenylbipyridyl (159b) were obtained by this method in small yields. 164 The low yields of reaction products were apparently associated with the presence of a bulky substituent in position 2 of salts 158a,b, which favoured the competitive reaction of N-demethylation of the starting compounds.…”

“…Heating of a mixture of 1,4-dimethyl-2-phenylpyridinium iodide (158a) or 1,4,4 H -trimethyl-2,2 H -bipyridylium iodide (158b) with 2-methylisoquinolinium 160 iodide (R 1 = Me) and methylammonium sulfite produced 4-naphthylpyridine (165a) or 4-naphthylbipyridyl (165b). 164 The introduction of a donor group into the benzene ring of isoquinoline hindered or even totally prevented the addition of the sulfite ion, so that the target product is formed in a considerably smaller yield or is not formed at all. Thus the yield of naphthylpyridinium 166 formed in the reaction of 1,4-dimethylpyridinium iodide 153 (R = Me) with 5-hydroxy-2-methylisoquinolinium iodide was only 22%.…”

“…Heating of isoquinoline and salts 158a,b with an aqueous methylammonium sulfite solution afforded 4-naphthylpyridine (165a) in 3% yield and 4-naphthylbipyridyl (165b) in 22% yield. 164 It was found that the nature of the counter-ion in quaternary salts of heterocyclic bases does not affect the efficiency of pyridine ring transformations.…”

Pseudorotaxane complexes of naphthylpyridines and naphthylbipyridyl with β-cyclodextrin and hydroxypropyl-β-cyclodextrin

“…7, 8 The stability constants were determined from fluorescence spectra by the parametric self modeling of the spectral matrix (PSSM) method, 9 which was developed for calculating the sta bility constants from electronic absorption spectra using corre sponding software. Experimental data were obtained by titrating the solution of the ligand-substrate complex with a solution of the ligand at a constant ligand concentration.…”