Azomethines nitroso compounds

Trifluoromethyl-substitutedazimines are surprisingly stable compounds. They are accessible by 1,3-dipole metathesis from tnfluoromethyl-substituted azomethine imines and certain nitroso compounds [187, 188] On photolysis, an electrocyclic ring closure first gives the triaziridines, which are stable at room temperature. On heating above 80-100 C, a valence tautomenzation takes place and azimines are formed [189] (equation 43). 

An analogous reaction is known with aromatic nitroso-compounds, but for it an exceptionally mobile hydrogen atom must be present in the ketone and hence no condensation occurs with simple ketones such Us acetone. The products of the reaction are, of course, azomethines. This condensation has made possible the synthesis of 1 2 3-triketones (F. Sachs), e.g. 

Alternatively, 2,3-dihydro-1,2,4-oxadiazoles are prepared by cycloaddition of nitroso compounds to azomethine ylides (223) (Scheme 96) <87T2223>. 

This chapter is concerned with dyes and pigments which are complexes of azo, formazan, azomethine, nitroso, anthraquinone and phthalocyanine ligands. Many of these compounds find important applications in other fields, particularly colour photography and reprography, analysis, catalysis, biology, and some modem high technology industries such as electronics. These applications are described in other chapters of this volume. 

Azidouracils. photolysis, 55, 197, 200 Azimines, pyrazole-derived, formation from azomethine imines and nitroso compounds, 60, 34 Azinium azolates, definitions, 60, 200 Aziridine... 

Electrochemical reduction of azobenzenes in DMF in the presence of succinyl chloride gives pyridazinediones in fair yield [128] a similar reaction with azomethine or nitroso compounds gave low or no yield of heterocyclic compounds. The reactions require dry media and unreactive solvent systems the reaction type may be illustrated by Eq. (20) ... 

Azomethines are formed by way of addition products, RR CH—NR"OH. In certain cases, however, these may be dehydrogenated by the nitroso compound to the nitrones, with simultaneous formation of azoxy compounds 434 435... 

Reaction of nitroso compounds with active methyl groups Nitrones and azomethines... 

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