Ultrasound Promoted Imino Diels-Alder Reaction Of Ketimine-Isatin For The Generation Of Spiro[Indoline-3,2,-Quinoline]-2-Onesusing Peg 400 As A Green Solvent Andevaluation Of Their Anti-Microbial And Analgesic Activity

Abstract

An easy, fast, elegantand eco-efficient protocol for the synthesis of spirotetrahydroquinoline derivatives(4a-h) has been explored through hetero Diels-Alder methodology by using arylamines(1a-h),indole-2,3-diones(2a/b)and maleic anhydridecatalysed byInCl₃in PEG 400 as green solvent under ultrasonication. Atom economical behavior, use of green solvent PEG 400 and ultrasonicationmakes this approach anattractive pathway to achieve complex molecules.Further, the feasibility of this reactionis demonstrated in terms of short reaction time, good yield and waste minimization. Synthesized compounds (4a-h)were confirmed by their spectral and analytical data. The coupling of two biologically active moieties i.e.indole and tetrahydroquinoline where there is a C-3 spirooxiindole bridge in the product molecules (4a-h) encouraged us for evaluating their anti-microbial and analgesic activities. Some of the compounds showed promising results for future prospects.