| 摘要 |
<p>Pyrroles of the formula I <IMAGE> (I) are prepared by a process in which a dialkoxytetrahydrofuran of the formula II <IMAGE> (II) where R2 to R5 in the formulae (I) and (II) are identical or different and are each hydrogen, a straight-chain or branched alkyl or alkenyl radical of not more than 12 carbon atoms, a cycloalkyl or cycloalkenyl radical of 5 to 8 carbon atoms, an aryl, alkylaryl or aralkyl radical of 6 to 16 carbon atoms, and two non-adjacent radicals R6 to R9 are alkoxy and the other two radicals R6 to R9 are hydrogen, is reacted with ammonia or a primary amine H2NR1, where R1 in formula (I) is hydrogen, alkyl, aryl, alkylaryl, aralkyl or cycloalkyl, in the presence of an acidic, solid, heterogeneous catalyst. Zeolites, for example those of the pentasil type or faujasite type, or phosphates, acidic oxides, phosphoric acid or boric acid on a carrier can be used as the solid heterogeneous catalysts.</p> |
