Pyridyl diazonium salts, reactions with

A few 3-cyanopyridines have been prepared, in 40-50 per cent yield, by reaction of a 3-pyridyl diazonium salt with potassium cuprocyanide or cuprous cyanide2i8, 755-7 Though 2- and 4-aminopyridines have been converted into 2- and 4-halogenopyridines via the diazonium reaction, the ready reaction of the 2- and 4-pyridyldiazonium ions with nucleophiles present in the solutions in which they are formed makes their use in cyana-tion difficult if not impossible. The difference in ease of diazotization between a 2- and a 3-aminopyridine permits the conversion of 2,5-diaminopyridine into 2-amino-5-cyanopyridine by diazotization in dilute acid is. The easier diazotization (p. 359) of 4-aminopyridine 1-oxides and the greater stability... 

Arylpyridines. The amino group of aromatic amines can be replaced by the pyridyl group by the normal diazohydroxide reaction,3 by treatment of the sodium diazotate in pyridine with acetyl chloride,17 by adding the dry diazonium salt to pyridine,18 and from the nitrosoacetyl... 

The requirement for the occurrence of the Japp-Klingemann reaction is the presence of a hydrogen atom of sufficient activity to permit the coupling with the diazonium salt. A methinyl group in the a-position of a pyridyl acetic acid 11 is reactive enough to participate in the Japp-Klingemann process.7... 

The chemistry of pyridylphosphines has been reviewed. Further studies have appeared of the reactions of phosphines bearing 2-pyridyl or 2-benzothiazolyl substituents with butyl-lithium, which result in the formation of biaryl coupling products via an initial nucleophilic attack at phosphorus. A study of the de-diazoniation of arenediazonium salts using triphenylphosphine (and trialkylphosphites) indicates that the reactions proceed via a radical-chain mechanism, initiated by single electron transfer from the phosphine to the diazonium salt, to give... 

A series of upper rim pyridyl azo calix[M]arenes ( = 4,6,8) have been synthesized by coupling calix[n]arenes with diazonium salts derived from 3-, 4-aminopyridine. In these reactions, the dizonium salt of... 

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