Immobilized palladium metal containing ionic liquid catalyzed one step synthesis of isoindole-1,3-diones by carbonylative cyclization reaction

• ImmPd-IL catalyst was explored for carbonylative cyclization reaction of o-halobenzoic acid.
• The influence of various reaction parameters was investigated.
• The developed catalytic system is phosphine free.
• The protocol is applicable for synthesis of wide variety of N-substituted isoindole-1,3-diones.
• The catalyst is effectively recycled for four consecutive cycles.

Immobilized palladium metal containing ionic liquid (ImmPd-IL) catalyzed carbonylative cyclization reaction of 2-iodobenzoic acid and primary amine provided N-substituted isoindole-1,3-dione derivatives in good to excellent yield. The influence of various reaction parameters including the effect of base, solvent, temperature, time and CO pressure on carbonylative cyclization reaction using ImmPd-IL catalyst was investigated. Using optimized reaction parameters different aromatic, aliphatic and heterocyclic N-substituted isoindole-1,3-dione derivatives were synthesized from corresponding aryl amines. The developed protocol is heterogeneous, phosphine free and requires attainable reaction conditions like atmospheric CO pressure and lesser reaction time. The scope of the developed protocol was also extended for the synthesis of N-substituted isoindole-1,3-diones from methyl-2-iodobenoate and 1,2-diiodo benzene. The ImmPd-IL catalyst was recyclable up to four consecutive cycles and recycled catalyst was characterized by XPS analysis.

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