Sandoz Gmbh

Roger Paver

Alec Victor Mercer

Fritz Fleck

The invention relates to stilbene derivatives which are used as optical brightening agents, particularly as anionic brightening agents for polyamide and cellulosic substrates. These stilbene derivatives have the formula I ##STR1## in which both X's are the same and are CR.sub.5 or N, where R.sub.5 is hydrogen, C.sub.1-4 alkyl or phenyl;

Bis-triazolyl and bis-pyrazolyl stilbene compounds

Disclosed are compounds of formula I, ##STR1## in which X signifies hydrogen, C.sub.1-4 alkyl, cyano, --COOM, --COOR.sub.1, --CONR.sub.2 R.sub.3, --SO.sub.2 NR.sub.2 R.sub.3, --SO.sub.2 R.sub.1, --SOR.sub.1, --SO.sub.3 R.sub.1 or --SO.sub.3 M,

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Bingley, United Kingdom

Roger Paver