Synthetic methodology and structure activity relationship study of N-[1-(2-phenylethyl)-piperidin-4-yl]-propionamides

N-[1-(2-Phenylethyl)-piperidin-4-yl]-propionamide (fentanyl) is the prototype of the 4anilidopiperidine class of synthetic opioid analgesics. This study was aimed to review the best method of synthesis and to determine the Structure-Activity-Relationship (SAR) of fentanyl analogs. The best method of synthesis of fentanyl is the method described in International Application No.: PCT/IN2009/000159. The advantages are as followedsimple, high yielding, cost effective, eco-friendly, environmentally safe, industrially feasible, does not require stringent process conditions, sophisticated infrastructure and specially skilled personnel. The objective of SAR studies is to discover compounds with adequate potency, greater selectivity and with enhanced pharmacokinetic properties in comparison to existing drugs.