Patent ID: 8709104

Claim:
A compound of the formula I where X stands for a single bond or a substituent of the formula IIa or IIb where * 1 is oriented towards the N═N, where: when X is a single bond, precisely one of the substituents R 1 to R 10 stands for a substituent of the formula IIIa, IIIb or IIIc; when X is of formula IIa, precisely one of the substituents R 1 to R 12 stands for a substituent of the formula IIIa, IIIb or IIIc; and when X is of formula IIb, precisely one of the substituents R 1 to R 10 , R 13 or R 14 stands for a substituent of the formula IIIa, IIIb or IIIc; where R 15 in each case stands, independently of one another, for an ascorbic acid radical of the formula IVa or IVb or a dehydroascorbic acid radical of the formula IVc or IVd, in each case as the L or D enantiomer, where the remaining substituents R 1 to R 14 each stand, independently of one another, for H, OH, NH 2 , NO 2 , F, Cl, Br, I, CF 3 , OCF 3 , O(C═O)—CH 2 —NH 2 , Alk 1 ,OAlk 1 , NHAlk 1 , NAlk 1 2 , Cyc, (NAlk 1 3 ) + x An x− , (SO 2 )NH 2 , (SO 2 )NHAlk 1 , O(SO 2 )OAlk 1 , O(SO 2 )OArl, (C═O)OAlk 1 , (C═O)OArl or Arl, where Alk 1 in each case stands, independently of one another, for a straight-chain or branched C 1 - to C 20 -alkyl group or for a straight-chain or branched C 2 - to C 20 -alkenyl group, which may have a plurality of double bonds, where at least one C atom or a plurality of non-adjacent C atoms of the C 1 - to C 20 -alkyl or C 2 - to C 20 -alkenyl group may be replaced by O, and where the C 1 - to C 20 -alkyl or C 2 - to C 20 -alkenyl group may have at least one OH, F, Cl, Br or I bonded to a primary or secondary C atom, where Arl in each case stands, independently of one another, for an unsubstituted, mono- or polysubstituted C 6 - to C 20 -aryl group, where Cyc stands for a C 3 - to C 8 -cycloalkyl group, which may have at least one double bond and/or in which at least one CH 2 may be replaced by O or NH, where An x− in each case stands, independently of one another, for an anion having the charge 1≦x≦3 or a tautomer or stereoisomer thereof, including mixtures thereof in all ratios.