Imidazoline Derivatives with Electrophilic Reagents

Interaction of Imidazoline Derivatives with Electrophilic Reagents 

Polarization of the C=N bond also causes electrophilic substitution of the alkyl group hydrogen in the a-position. Interaction of 1-hydroxy-3-imidazoline-3-oxide (6a) with aromatic aldehydes in the presence of bases, similar to the case observed for heterocyclic iV-oxides (Ochiai, 1967 Katritzky and Lagowski, 1971 Hansen and Boyd, 1970), leads to l-hydroxy-4-arylvinyl-3-imidazoline-3-oxides (41), oxidation of which generates nitroxides 42. The action of an equimolar amount of amyl nitrite on l-hydroxy-4-methyl- and l-hydroxy-4-ethyl-3-imidazoline-3-oxides 

Condensation of compound 6a with terephthalic dialdehyde (Schapiro et al, 1976) and interaction of compound 6a with nitrosobenzene (Volo- 

For less reactive 3-imidazoline derivatives containing no iV-oxide oxygen only a nitrosation reaction has been realized, and its results depend on the conditions under which the reaction is conducted. Slow addition of two equivalent amounts of amyl nitrite to nitroxides 13a,b or to 1-hydroxy-4-methyl-3-imidazoline (12a) in liquid ammonia in the presence of sodium amide produces nitroxyl oximes 52a,b. The immediate treatment 

Nitroenamine radical 53 exists in trans (A) or cis (B) forms form A crystallizes from alcohol, and on dissolution in chloroform it passes into form B, stabilized by the intramolecular hydrogen bond. Treatment of compound 53 with sodium ethylate leads to the formation of the sodium salt of aciform 54, and the action of an equimolar amount of bromine or of excess bromine leads, correspondingly, to mono- and dibromo derivatives 55 and 56. 

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Thus, the interaction of 3-imidazoline derivatives and 3-imidazolinium salts with electrophilic reagents makes it possible to obtain various derivatives of this series, containing a nitroxyl radical center. 

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