Pyridinium thiophenolates

Compounds of this type (298) have been made from 4-aminothiophenol and 2,4,6-triarylpyrylium salts.  

The I UP AC-recommended name for this ring system tends to obscure its structural relationship to the others in succeeding sections (III,C,6—10), so an alternative, although strictly incorrect, form is included in the heading. 

Benzisoquinolines (303) have not been isolated, but they have been generated in situ and trapped as 1,3-dipolar adducts. Treatment of the 

Dimroth, C. Reichardt, T. Siepmann, and F. Bohlmann, Justus Liebigs Ann. Chem. 661, 1 (1963). 

These unusual sulfur heterocycles (310 R = H,Ph) have been generated in situ by Pummerer dehydration of the sulfoxides 312 (R = H, Ph). Isolation of the betaines has not been achieved, but they are trapped in high yield by A -phenylmaleimide giving the exo adducts (313 R = H, Ph, R = This is in sharp contrast to the corresponding nitrogen 

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Perdue, E.M, "Thermodynamics of Acid-Base Equilibria. Substituted Anilinium Ions, Pyridinium Ions and Thiophenol." Ph.D. Thesis, Georgia Inst. Tech., Atlanta, 1973. 

Addition of thiophenol to cyclopropylallene 12, a less common method for the preparation of cist tram mixtures of divinylcyclopropanes, is used in the synthesis of karahanaenone850, an odoriferous constituent of Japanese hop and cypress oil. Karahanaenone is also prepared via a silyloxy-Cope rearrangement of 15 in 54% overall yield (starting with isobutyraldehyde and a mixture of cis- and /rpyridinium chlorochromate oxidation to give 14)851-852,... 

N-(2-mercapto-3-thienyl)-pyridinium betaines Thiophenol (s. a. Sodium thiophenoxide)... 

Amino-4,6-diacetamido-5-nitrosopyrimidine allowed to react with l-(cyano-methyl)pyridinium chloride and thiophenol in aq.-alc. NaOH 2,4,7-triamino-6-phenylthiopteridine. Y 71%. F. e., also with 4-amino-5-nitrosopyrimidines, s. W. W. Parish and H. Smith Broadbent, J. Heterocyclic Chem. 5, 527 (1971). 

Thiophenol and CSg added under argon to a degassed soln. of l-(l-benzoylpro-pyl)-pyridinium iodide in CHClg, and irradiated 3 hrs. with the Pyrex-filtered light of a high-pressure Hg-lamp 1-phenyl-l-butanone. Y 86%. F. e. s. T. Ta-keda and T. Mukaiyama, Chem. Lett. 1976, 477. 

Arylations are commoner than alkylations. Ullmann and Nadai s preparation of dinitrochlorobenzenes, and its extension to that of diphenyl ethers—reactions in which the nucleophiles are chloride ions and phenols, respectively—have been mentioned already (p. 268). Applied to l-(2,4-dinitronaphthyl)pyridinium chloride, the reaction gives l-chloro-2,4-dinitronaphthalene, and the same salt reacts with water to give the naphthol, with hydrogen sulphide to yield the thionaphthol, and with carboxylic acids to form dinitronaphthyl esters . Amines , alcohols , mercaptans and thiophenols have been dinitrophenylated with pyridinium salts. Styrylpyridinium salts give N-styrylpiperidine with piperidine . 

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