Preparation of pyrroles from dialkoxytetrahydrofurans

Abstract

Pyrroles of the formula I ##STR1## are prepared by a process in which a dialkoxytetrahydrofuran of the formula II ##STR2## where R.sup.2 to R.sup.5 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 R.sup.6 to R.sup.9 are alkoxy and the other two radicals R.sup.6 to R.sup.9 are hydrogen, is reacted with ammonia or a primary amine H.sub.2 NR.sup.1, where R.sup.1 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.

Dependencies are inferred from the claim text.