Green synthesis of bioactive phenolics employing ionic liquids and microwave assisted approaches

Abstract

This thesis is divided into four chapters: Chapter 1 Ionic liquid and microwave assisted dehydration of arylalkanols into (E)- arylalkenes under neutral condition Chapter 2 Synergism of ionic liquid and microwave towards metal-free activation of H2O2 for oxidation of benzyl alcohols Chapter 3 Structure-activity relationship of chalcones and their derivatives for antimalarial and pesticidal activity Chapter 4 Microwave promoted tandem C-C bond formation strategy in ionic liquid for synthesis of stilbenoids Chapter 1: Ionic liquid and microwave assisted dehydration of arylalkanols into (E)- arylalkenes under neutral condition. Dehydration is an important and frequently desired transformation in organic synthesis due to immense biological and synthetic utility of ensuing alkenes. However, the most common approaches for dehydration employ harsh Lewis/Bronsted acid catalysts which not only preclude their use with substrates possessing sensitive functional groups but also lead to deleterious environmental impact. This chapter describes a new approach for the dehydration of arylalkanols in neutral conditions using ionic liquid [hmim]Br as a catalyst as well as solvent under microwave irradiation. The developed protocol offers several inherent benefits like recyclability of ionic liquid, reduction in waste and hazards, shorter reaction time besides ease of product recovery. Chapter 2: Synergism of ionic liquid and microwave towards metal-free activation of H2O2 for oxidation of benzyl alcohols. newlineOxidation of alcohols to corresponding carbonyl compounds is an important and challenging transformation in organic chemistry. However, oxidation involving use of H2O2 as a green oxidant has remained one of the most demanding transformations often requiring activation by metal catalysis. The present chapter describes a unique synergism of ionic liquid and microwave for the activation of H2O2 without any metal catalyst in aqueous condition.