ChemInform Abstract: Studies on the Double Mannich Condensation Reaction of o- Phthalaldehyde with p-Substituted Anilines in the Presence of 1,2,3-1H- Benzotriazole.

Abstract

The double Mannich condensation reaction in acetonitrile at room tempe- rature has been investigated. In the condensation reaction of o-phthal- aldehyde (1) with p-toluidine (2a; 1 equiv.) in the presence of 1,2,3- 1H-benzotriazole (Bt-H), the use of 3 equiv. of Bt-H afforded Bt-subs- tituted isoindoline derivative (4a) exclusively for 8 h, and the use of 4 equiv. of Bt-H did for 4 h; further increment of reaction time induced the dissociation of Bt-H from (4a) to give 2H-isoindole derivative (5a). On the other hand, when methyl p-aminobenzoate (2b) was used ins- tead of (2a), the rate of the formation of isoindoline (4b) increased as the amount used of Bt-H was large (2 → 3 → 4 equiv.). Different from the 2-p-tolyl) counterpart, the increment of the reaction time did not induce the dissociation of Bt-H to afford 2H-isoindole derivative (5b)