23  US 7,144,993 B2  24  11.  A compound of the formula  9.  A process according to claim  3,  wherein the conversion  of a compound of formula III into a compound II and of the  resulting compound of formula II into a compound of  formula I is carried out as a one-pot reaction.  10.  A process according to claim  1,  wherein a compound  of formula I is reacted with a suitable coupling component  to form a compound of formula  (I)  (VI)  wherein R 5 , R $^{6 }$and R8 are each independently of the others  a hydrogen atom, a nitro group, a sulfa group, a halogen  atom, a pseudohalogen, a group COOR 1  or CONHR 2  or a  C$_{1}$ _ $_{8}$alkyl, C$_{1}$ _ $_{8}$alkoxy or aryloxy radical, an amide group, a  thioalkyl or thioaryl radical, an alkyl- or aryl-sulfonyl radi› cal, an alkyl- or aryl-sulfinyl radical, a trifluoromethyl group  or a phosphono group, R$^{1 }$and R$^{2 }$being a hydrogen atom, a  C$_{1}$_$_{8}$alkyl radical or an aryl or aralkyl radical,  having an isomeric purity of more than 95%.  *  *  *  *  *  R  5 ,  R  6  and R  8  being as defined in claim  1  and A being the  radical of a coupling component.  H  A-N=N  N  0,  R6  #  Rs  CH3 