Ciba-Geigy Corporation

Hans-Peter Horner

Dieter Baumann

Claus W Rabener

Compounds of the formula Ia or Ib ##STR1## in which R.sub.1 and R.sub.2, independently of one another, are hydrogen, alkyl, cycloalkyl, alkenyl, aryl or aralkyl or, together with the carbon atoms in the .alpha.-position to the carbonyl groups, form a cyclopentane, cyclopentene, cyclohexane, cyclohexene, cyclohexadiene or bicyclo[2.2.1]hept-5-ene ring which is unsubstituted or substituted by C.sub.1 -C.sub.4 alkyl, or form a monocyclic or polycyclic, aromatic ring system which is unsubstituted or substituted by C.sub.1 -C.sub.4 alkyl, R.sub.3 and R.sub.4, independently of one another, are hydrogen, alkyl, alkenyl, aryl or aralkyl, and R.sub.5 and R.sub.6, independently of one another, are alkyl, aryl or aralkyl groups, are highly suitable as flame retardants for polymers.

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Wehr, Germany

Hans-Peter Horner