| abstract |
3-(3,4,5,6-Tetrahydrophthalimido)-benzaldehydes of the type I <IMAGE> I or corresponding derivatives substituted in the phenyl ring are prepared by (a) acetalization of a 3-nitrobenzaldehyde III or of a corresponding derivative with an alcohol IV in the presence of an acidic catalyst to give the corresponding cyclic acetal V <IMAGE> V (b) reduction of the cyclic acetal V with hydrogen to give the corresponding amino compound II and (c) subsequent condensation of this aminophenyl acetal II with 3,4,5,6-tetrahydrophthalic anhydride in an acidic reaction medium. |