Electrochromic marking systems

摘要

3-(N-R2-N-Acylamino)-7-(N-R3-N-R4-amino)-10-acylphenothiazines and phenoxazines useful as color formers, particularly in electrochromic recording systems, are prepared by the interaction of the corresponding 3-(N-R2-amino)-7-(N-R3-N-R4-amino)phenothiazinium or phenoxazinium halide with a reducing agent to obtain the corresponding leuco compound and subsequently interacting the leuco compound with at least two molecular proportions of an acylating agent.