Preparation of pyrocatechol monoethers and pyrocatechols

摘要

The preparation of pyrocatechol monoethers or pyrocatechols of the formula Ia or Ib respectively Ia Ib ( R1 and R2=H or C1-C8-hydrocarbon radicals; R3=C1-C8-hydrocarbon radical ) by rearranging a 2-hydroxycyclohexanone dialkyl ketal II II a) in the gas phase in the presence of a platinmetal or in the presence of a compound of one of these metals as catalyst in order to obtain a compound Ia, or b) carrying out step a) in the presence of water in order to obtain a compound Ib. The products are used as intermediates in the synthesis of pharmaceuticals, fragrances and flavors.