I 'm going to present here a two step PEPAP synthesis.
Step 1: Synthesis of 1-(2-phenylethyl)-4-phenyl-4-piperidinol
A mixture of 2-phenylethylamine (121 g), an equivalent amount of concentrated hydrochloric acid (93 ml), alpha-methylstyrene (118 g) and aqueous 37 % formaldehyde (200 g) was stirred and heated at 80 °C for 3 hours. The resultant clear solution was refluxed for 5 hours and left at room temperature overnight. The product, consisting of 2 layers, was washed with benzene (3 x 100 ml), made alkaline with aqueous 50 % NaOH solution and extracted with benzene (3 x 100 ml). After drying (K2CO3) approximately 200 ml of solvent was evaporated and the residue diluted with n-hexane until a faint permanent cloudiness was obtained. The crystals which separated on cooling were collected and recrystallized from light petroleum (b.p. 80 - 100 °C) to give 1-(2-phenylethyl)-4-phenyl-4-piperidinol (36.7 g) needles, m.p. 102 - 103 °C.
Step 2: Acetylation
A mixture of 1-(2-phenylethyl)-4-phenyl-4-piperidinol (2 g), acetic anhydride (3 ml) and pyridine (3 ml) was refluxed for 3 hours and the solvents were removed under reduced pressure. The residue was converted into a hydrochloride and recrystallized from ether-ethanol.
M.p. PEPAP.HCl: 214 - 215.5 °C