Process for preparing (3-oxo-2,3-dihydro-1H-isoindol-1-yl) acetylguanidine derivatives

A compound of the formula XVa or XVb

• wherein
• R1 and R2
• are each independently hydrogen, F, Cl, trifluoromethoxy, 2,2,2-trifluoroethoxy, trifluoromethyl, 2,2,2-trifluoroethyl or alkyl having 1, 2, 3 or 4 carbon atoms;
• R3 is Alk-R4, trifluoromethyl, alk is alkyl having 1, 2, 3 or 4 carbon atoms;
• R4 is hydrogen, trifluoromethyl or cycloalkyl having 3, 4, 5, 6 or 7 carbon atoms;
• R* is
• R8 is alkyl having 1, 2, 3, 4, 5 or 6 carbon atoms or phenyl which is unsubstituted or substituted by 1, 2 or 3 substituents from the group of F, Cl, Br, I, alkyl having 1, 2, 3 or 4 carbon atoms or alkoxy having 1, 2, 3 or 4 carbon atoms.