Non-Infringing Efficient One-Pot Process for the Preparation of Pure Entacapone

A new and non-infringing efficient one-pot process for the preparation of catechol-O- methyltransferase (COMT) enzyme inhibitors, entacapone 1 under mild condition, initially reaction 3-methoxy-4-hydroxy-5-nitro-benzaldehyde 5 with 2-cyano acetic acid 13 in presence organic base benzyl Trimethyl ammonium hydroxide, i.e. Triton-B which undergo Knoevenagel condensation to get intermediate 22 is then react SOCl2 chloride 23 diethylamine 6 finally deprotection HBr-AcOH economically industrially feasible higher purity yield without isolation any as compared conventional batch wise process.