The glassy solid tert-butyl 1-(4-(5-(2-(1-phenylcyclohexyl)ethyl)-1,2,4-oxadiazol-3-yl)benzyl)azetidine-3-carboxylate was dissolved in 3 mL of 4N HCl in dioxane, and the mixture was stirred for 5 h. The reaction was followed by LC/MS and was evaporated and dried in vacuo. The residue was purified by prep. HPLC (Phenomenex S10 30×100 mm, 40 min gradient time, Detection Wave length 220 nm, Starting solvent: 10% aq. MeOH—0.1% TFA; Final solvent: 90% aq. MeOH—0.1% TFA) to give the 1-(4-(5-(2-(1-phenylcyclohexyl)ethyl)-1,2,4-oxadiazol-3-yl)benzyl)azetidine-3-carboxylic acid (47.5 mg, yield=21%) as a white solid. LC/MS: m/e 446.17 (M+H)+. 1H NMR (400 MHz, CD3OD): δ ppm 8.1 (d, J=8.28 Hz, 2H), 7.61 (d, J=8.28 Hz, 2H), 7.40-7.46 (m, 2H), 7.32-7.39 (m, 2H), 7.14-7.21 (m, 1H), 4.49 (s, 2H), 4.36 (d, J=7.28 Hz, 4H), 3.66-3.77 (m, 1H), 2.55-2.69 (m, 2H), 2.2-2.33 (m, 2H), 2.04-2.19 (m, 2H), 1.33-1.79 (m, 8H).
