. . "The compound of formula (I) may be used as oxidiation bases in the presence of couplers such as metadiphenols, metaphenylenediamines, metaaminophenols, as well as couplers corresponding to the general formula ##STR5## in which formula R3 and R4 are identical or different and may represent a hydrogen atom, alkoxy radical, or an alkyl radical and in which R5 is a radical selected in the group formed" . .