Monoazo compounds and process for preparing the same

摘要

The present invention provides a monoazo compound represented by formula (1) or a salt thereof: wherein, Y₁ and Y₂ represent a group selected from hydrogen atom, formula (2) and formula (3); provided that at least one of Y₁ and Y₂ is a group represented by formula (2); Z is a group selected from formulae (4), (5) and (6);