Verfahren zur Herstellung organischer Radikalverbindungen

摘要

The invention comprises organic radical compounds of the general formula in which R1 is hydrogen, an alkyl group or an aromatic hydrocarbon group which may be substituted by halogen, R2 and R3 are aromatic hydrocarbon groups which may be substituted by halogen or alkoxy groups and R4 is hydrogen, an alkyl or an aromatic hydrocarbon group which may be substituted by halogen. They may be prepared by the reaction of a N,N1-diarylformazan of the general formula with an aldehyde of the general formula R4CHO, with an acetal or polyacetal of such an aldehyde or with a dihalogen compound of the general formula Alternatively, the diarylformazan may be reacted with a compound of formula X-CH2-R4 in which X is halogen, an alkyl sulphate or a sulphonate group and the resultant compound is simultaneously or subsequently dehydrogenated. Suitable formazans for use as starting materials are, for example, N,N1-diphenylformazan, N,N1 - diphenyl - methyl - formazan, triphenylformazan and N - (o - methoxyphenyl) - N1 - phenyl - C - phenylformazan. Suitable aldehydes are, for example, propionaldehyde, phenylacetaldehyde, acetaldehyde and formaldehyde. Alternatively, compounds with an aldehyde function, e.g. paraformaldehyde, 1,3,5-trioxan, paraldehyde, aldehyde hydrates and acetals or alkylidene or aralkylidene halides such as methylene iodide and benzal chloride, which give aldehydes or hydrolysis may be used. The reaction is preferably carried out at a temperature in the range 0-20 DEG C. and may be carried out in acid or alkaline media. Suitable compounds of formula XCH2R4 are, for example, dimethyl sulphate, methyl iodide, benzyl bromide and p-bromobenzyl bromide and the reaction with these is preferably carried out in a solvent, e.g. dimethylformamide and dimethyl sulphoxide, at a temperature in the range 0-20 DEG C. The dehydrogenation is carried out by usual agents, e.g. air, oxygen or potassium ferricyamide.