3- HYDROXYTRIAZENES

The reaction of arenediazonium ions with hydroxylamine is known, but has been little investigated (Gattermann and Ebert, 1916). The l-aryl-3-hydroxytriazene (6.23) formed initially is in most cases unstable (except if Ar = anthraquinonyl). Under alkaline conditions elimination of N20 yields the amine, whereas the aryl azide is formed in the presence of acid (Scheme 6-15). There are, however, better methods for the synthesis of aryl azides (review Biffin et al., 1971, p. 147). 

The reactions of arenediazonium ions with 7V-alkyl- or 7V-arylhydroxylamines were investigated by Bamberger (1920b, and earlier papers). Mitsuhashi et al. (1965) showed that the l,3-diaryl-3-hydroxytriazenes are tautomeric with 1,3-diaryltriazene-3-oxides (Scheme 6-16). Oxidation of 1,3-diaryltriazenes with peroxybenzoic acid in ether yields the same product as that from diazonium salts and TV-arylhydroxyl-amine. The infrared spectrum of the product obtained by coupling diazotized relabeled aniline with A/-phenylhydroxylamine indicates that the diaryltriazene-oxide is the preponderant tautomer. 

Many of the 3-hydroxytriazene derivatives produced by diazo-coupling onto N-alkyl or A-aryl hydroxylamines decompose explosively above their m.p.s. However, the heavy metal derivatives are stable and used in analytical chemistry. 

Phenyl-3 -/er/-buty ltriazene, 3335 Silver 3-cyano-l-phenyltriazen-3-ide, 2670 Silver l,3-di(5-tetrazolyl)triazenide, 0690 See 3-CYANOTRIAZENES 3-HYDROXYTRIAZENES 3-NITROSOTRIAZENES... 

Hydrogenation catalysts, 182 Hydrogenation incidents, 183 Hydrogen transfer, 184 Hydroxooxodiperoxochromate salts, 184 Hydroxylaminium salts, 185 3-Hydroxytriazenes, 185 Hypohalites, 185... 

Diaryltriazene 1-oxides (16, Equation 99.13 tautomeric with 3-hydroxytriazenes 17) are photo-chemically cleaved, giving finally the products from fragment recombination, viz. biphenyls and azoxy-benzenes, as well as the products from the secondary photolysis of the latter derivatives. ... 

C. Some Other Related Species that will be Ignored Hydroxylamines, Nitrosohydroxylamines, Hydroxytriazenes... 

Having chosen to ignore amidoximes with the general formula R C(NR R )=N—OH legitimizes our decision to ignore in this chapter A-hydroxytriazenes with their functionality R N(OH)—N=N—R (or are they the tautomeric triazene A-oxides, R N(0)= N—NH—R ) because they are all A-substituted hydroxylamines. 

Some references are given for the curious reader on amidoximes" ", on A-nitrosohy-droxylamines" and on A-hydroxytriazenes" . 

VO(LL02a] quinaldinate, N- - and A-3-substituted hydroxytriazenes, big , pyc a = solvent molecule, aromatic amine, heterocyclic base... 

The monomers needed for the polymer support synthesis were prepared as depicted in Scheme 3.15. Compound 11 was converted to the diazonium intermediate which was captured with 2-(ethylamino)ethanol, to form the hydroxytriazene according to Moore s protocol. Silylation to form 47 followed by acetyl conversion to the silylalkyne afforded 48. Compound 48 was divided into two portions the first portion was desilylated to form 49, the anchor unit to be attached to the polymer support. The second portion was iodinated to form the iodoarene 16. 

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