5-Sulfosalicylic acid an organocatalyst for the synthesis of highly functionalized piperidines through the multicomponent reaction

The synthetic protocol was developed for the synthesis of highly derivatized piperidines molecules in high yield with 5-sulfosalicylic acid as an organocatalyst via a multicomponent reaction between the aromatic aldehydes, the aromatic anilines, and the beta-ketoesters at room temperature. The method has numerous advantages over other reported methods, such as the use of an inexpensive, reusable, nontoxic, and metal-free catalyst along with readily available precursors, mild reaction conditions, and simple workup procedures. Instrumental techniques like high-resolution mass spectroscopy (HRMS), proton nuclear magnetic resonance (H-1 NMR), 13-carbon nuclear magnetic resonance (C-13 NMR), and Fourier transform infrared (FTIR) spectroscopy were used to confirm the structure and relative stereochemistry of the compounds. In this protocol, an anti-isomer has been obtained as a major product at room temperature. Syn: Anti diastereomeric ratio has been confirmed by H-1 NMR.