Amino-iminoisoindolenine benzene sulfonate, and process for the preparation of nitrate and benzene sulfonate salts of amino-aminoisoindolenine derivatives

A process for the preparation of isoindolenine salts of formula (I), wherein R1, R2, R3 and R4 are each independently of one another hydrogen, halogen, C1-C4-alkyl, C1-C4alkoxy, phenoxy, -NHR5 or -N(R5)2, R5 is C1-C4alkyl, and X is NO3, or (1) by reacting 1 mol of a compound of formula (II), wherein Y is O or NH, with 3 to 10 mol of urea and a) if X is NO3, with 1 to 3 mol of a mixture consisting of ammonium nitrate and 5 to 90 mol%, based on the ammonium nitrate, of an ammonium salt of formula (III): NH4Z, wherein Z is 1/2 SO4 or Q SO3, and Q is C1-C24alkyl, unsubstituted or C1-C4alkyl-substituted phenyl or naphthyl, or b) if X is (2) either with 2 to 4 mol of ammonium benzenesulfonate or 1 to 2 mol of a mixture consisting of ammonium benzenesulfonate and 5 to 50 mol% of ammonium nitrate, based on the ammonium benzenesulfonate, in the temperature range from 150 to 220 DEG C and subsequently processing the resultant product by customary methods. This process substantially improves the stirrability of the reaction mixture at the end of the reaction. Additionally, the isoindolenine salts of formula (I), wherein X is benzene sulfonate.