Research

Chemical Sciences

Title :

Acceptorless dehydrogenative coupling with Ir-based catalysts for the synthesis of quinolines, pyridines and pyrroles

Area of research :

Chemical Sciences

Principal Investigator :

Dr. Raajesh Kumar Das, University Of North Bengal, West Bengal

Timeline Start Year :

2024

Timeline End Year :

2027

Contact info :

Equipments :

Details

Executive Summary :

Heterocyclic compounds containing nitrogen atoms, such as quinoline, pyrrole, and pyridine derivatives, are crucial in synthetic organic chemistry and have various biological and pharmacological properties. However, traditional pyrrole synthesis methods are expensive, time-consuming, and produce hazardous waste. Insufficient functional group tolerance, unstable substrates, and insufficient starting materials supply limit their applicability. To address these issues, modern, atom-economic and greener methodologies are highly desirable for synthesizing these compounds. Modern, environment-friendly techniques can reduce the chemical industry's environmental impact and costs associated with high temperatures and waste treatment. To address these shortcomings, a group of three Ir-(III) complexes (CCDC 2165585) was synthesized, supported by a picolinamidato moiety. These catalysts can build C-C and C-N bonds with alcohol via an acceptor less dehydrogenative coupling (ADC) process. However, the product yield and conditions applied are not atom-economic. The methodology involves ketone with 2-aminobenzyl alcohol, a Cp*Ir(III) catalyst, low base, and short reaction time with TON 323, temperature 90°C. The aim is to synthesize substituted pyrrole and pyridine compounds by changing starting materials and conducting a DFT study to understand the plausible mechanistic path. To the best of our knowledge, few Cp*Ir(III)-based catalytic reactions have been reported without an acceptor. Our methodology offers a minimum catalyst, more economical conditions, hydrogen and water as by-products, excellent yield, and highest cumulative turn-over frequency (TOF) compared to others.

Total Budget (INR):

26,44,994

Organizations involved