Xanthenedione Substituted Metallophthalocyanines as an Efficient and Recyclable Catalyst for One-pot Three Component Synthesis of 3-Substituted Indoles

An efficient one-pot methodology for the synthesis of 3-amino-alkylated indoles catalyzed by metallophthalocyanines has been developed via a three component Mannich type reaction with secondary amines, aldehydes and indoles. The newer catalysts i.e. metallophthalocyanines were synthesized by tetramerization of xanthenedione substituted phthalonitrile in anhydrous N, N-dimethylformamide by conventional heating and microwave conditions and were characterized by different spectroscopic techniques. The aggregation behaviors of these metallophthalocyanines were studied at different concentration in dimethyl sulfoxide and it was observed that these metallophthalocyanines show monomeric behavior in DMSO. The catalyst was separated from the reaction medium, characterized and was successfully reused up to five catalytic cycles. It was observed that the catalyst is stable in the catalytic system. Based on observations, a suitable reaction pathway is proposed for the current reaction.