| 摘要 |
New quinoxaline di-N-oxide derivatives of the formula <IMAGE> are prepared. In this formula, R1 and R2 independently of one another denote hydrogen, methyl, acetyl, ethoxycarbonyl, carbamoyl, methylcarbamoyl, dimethylcarbamoyl, diethylcarbamoyl, beta -hydroxyethylcarbamoyl, benzoyl, phenylthio, pyridyl, N-oxipyridyl, the amino or the cyano radical, R3 represents C1-C8-alkyl, dimethylaminoethyl, diethylaminoethyl, 2-hydroxyethyl or 2,3-dihydroxypropyl and n denotes 0, 1 or 2. The radical R3-S(O)n takes the 6- or 7-position on the phenyl ring. The quinoxaline compounds are obtained by reacting substituted benzofurazan N-oxide compounds with substituted carbonyl compounds in the presence of a base at temperatures of from 20 DEG to 70 DEG C and, for specific end products, with malononitrile under the same process conditions. If appropriate, the compounds in which n is zero are converted to a higher oxidation state by treatment with an oxidising agent. The compounds prepared possess valuable microbicidal and growth-promoting properties in animals. For use in practice, they can be converted together with suitable auxiliaries into solid or liquid compositions suitable for application. They are suitable, for example, for the preparation of concentrated premix formulations for mixing with standard feed, or of ready-made feed mixes.
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