Pd supported Al-BDC MOF for efficient and selective N-methylation of amines under solventless conditions

Efficient and selective N-methylation of amines stands as a pivotal process in organic synthesis, enabling the synthesis of bioactive compounds and pharmaceuticals. Recent advances in catalytic and sustainable methods have emphasised the utilisation of transition metals, organocatalysts and green chemistry principles for direct N-methylation. In present work, the Al-BDC metal-organic framework (MOF) was synthesised via a solvothermal method, with Pd nanoparticles subsequently incorporated through simultaneous pore activation and chemical reduction of Pd precursor. Comprehensive characterisation using FTIR, FESEM, HRTEM, EDS and XPS validated the synthesised Pd@Al-BDC MOF. The heterogeneous Pd-supported MOF catalyst, when utilised for N-methylation of aniline derivatives under solventless conditions, facilitated the N-methylation of aniline derivatives with dimethyl carbonate (DMC), yielding N-methylated products in an exclusive manner. Reaction parameters, including catalyst concentration, amines/DMC mole ratio, duration and temperature, were systematically studied. When compared to the previous literature, the present study confers a novel eco-friendly approach that generated the methylated amines using a safer methylation source under solventless conditions in the presence of heterogenous and reusable catalyst.