5-Sulphosalicylic Acid: An Expeditious Organocatalyst for One128;‘pot Synthesis of Indenopyrazolones and its Derivatives

An efficient, 5-Sulphosalicylic acid (5-SSA) catalysed green protocol for the synthesis of Indenopyrazolones and its derivatives is reported under metal-free conditions in an ethyl lactate system. The main advantages of this procedure include the use of an organocatalyst, ethyl lactate as a recyclable promoting media, practical simplicity, high yields, shorter reaction times, atom economy, and ease of isolation of the product. These results showed that aromatic aldehydes with electron- withdrawing groups reacted faster than aldehydes with electron-releasing groups as expected. According to these observations, aromatic aldehydes with electron-withdrawing groups reacted more quickly than aldehydes with electron-releasing groups.