One-Pot, Three-Component Synthesis of Dialkyl 1,2-Dihydroquinoline-2,3-Dicarboxylates from Triphenylphosphine, Acetylenic Esters, and Amide Derivatives of 2-Aminobenzaldehyde in Aqueous Acetone

Abstract

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates by amide derivatives of 2-aminobenzaldehyde in the mixture of acetone-water (3:1) leads to vinyltriphenylphosphonium salts, which undergo a Michael addition reaction with a conjugate base to produce the corresponding stabilized phosphorus ylides. An intramolecular Wittig reaction of the stabilized phosphorus ylide group with the aldehyde group leads to the corresponding dialkyl 1,2-dihydroquinoline-2,3-dicarboxylates.

Keywords:

• 2′-Formylacetanilide
• 2′-formylbenzanilide
• acetylenic ester
• intramolecular Wittig reaction
• triphenylphosphine

The authors gratefully acknowledge the financial support of the Zanjan Islamic Azad University Research Council via research project number ZIAURC6.82.11888. We also thank Dr. Mehdi Rahnema (rector of Zanjan Islamic Azad University Research Council) for helpful discussions.