Process for the preparation of dioxazine compounds

摘要

The present invention relates to a process for the preparation of dioxazine derivatives of the formula I in which R1 is hydrogen or (C1-C8)-alkyl, by ring closure of a compound of the formula II in the presence of a ring-closure agent, wherein the ring-closure agent used is an N-hetarene N-oxide. The compounds of the formula I are used for producing valuable dyes and pigments.