An Efficient and Facile Synthesis of 2‐Amino‐4 <i>H</i> ‐pyrans &Tetrahydrobenzo[ <i>b</i> ]pyrans Catalysed by WEMFSA at Room Temperature
Prashant B. Hiremath, K Kantharaju
Abstract
Abstract An eco‐friendly and facile three‐component reaction for the synthesis of 2‐amino‐4 H ‐pyran and tetrahydrobenzo[ b ]pyran derivatives is established using agro‐waste based Water Extract of Muskmelon Fruit Shell Ash (WEMFSA) as a catalyst. The present method offers several advantages such as efficient, mild reaction condition, simple product isolation and economic approach at room temperature in the absence of an external base or ligand/catalyst/additives. Thus, this approach is a very good alternative to existing protocols, because of non‐hazardous catalyst and mild condition use. Muskmelon fruit dried shells underwent thermal treatment followed by deionised water soak gave WEMFSA catalytic media. It is notable that, this method is found to be clean and high yielding target product isolation using simple filtration after reaction mixture dilution with water and analytical pure form was obtained after recrystallization with absolute ethanol. The synthesized products are characterized using various spectroscopic methods such as FT‐IR, 1 H‐, 13 C‐NMR and mass spectrometry techniques.