4-Fluorofentanyl 90736-23-5 DEA No. 9812 N-(4-Fluorophenyl)-N-(1-(2-phenethyl)-4-piperidinyl)propanamide N-(4-Fluorophenyl)-N-(1-(2-phenylethyl)-4-piperidinyl)propanamide Propanamide, N-(4-fluorophenyl)-N-(1-(2-phenylethyl)-4-piperidinyl)- p-Fluorofentanyl