Trifluoroacetic acid → 3-(3-(4-(5-(2-(1-(3,5-Dichlorophenyl)cyclohexyl)ethyl)-1,2,4-oxadiazol-3-yl)phenyl)-3-hydroxy-1-azetidinyl)propanoic acid

Participants

Reaction Conditions

Reaction Steps

tert-Butyl 3-(4-(5-(2-(1-(3,5-dichlorophenyl)cyclohexyl)ethyl)-1,2,4-oxadiazol-3-yl)phenyl)-3-hydroxyazetidine-1-carboxylate (56 mg, 0.098 mmol, HPLC purity: 80%) was treated with TFA in dichloromethane for 1 h and concentrated. The residue was dissolved in 2-propanol (3 mL). tert-Butyl acrylate (0.143 mL, 0.978 mmol) and diisopropylethyl amine (0.034 mL, 0.196 mmol) were added and the mixture was heated to 80° C. overnight. The reaction mixture was concentrated and then treated with TFA in dichloromethane for 3 h. The mixture was concentrated and a DMF solution of the crude material was purified via preparative LC/MS with the following conditions: Column: Waters XBridge C18, 19×250 mm, 5-μm particles; Guard Column: Waters XBridge C18, 19×10 mm, 5-μm particles; Mobile Phase A: 5:95 methanol:water with 10-mM ammonium acetate; Mobile Phase B: 95:5 methanol:water with 10-mM ammonium acetate; Gradient: 45-100% B over 25 minutes, then a 5-minute hold at 100% B; Flow: 20 mL/min. Fractions containing the desired product were combined and dried via centrifugal evaporation to obtain 3-(3-(4-(5-(2-(1-(3,5-dichlorophenyl)cyclohexyl)ethyl)-1,2,4-oxadiazol-3-yl)phenyl)-3-hydroxy-1-azetidinyl)propanoic acid (30 mg, 56% yield). HPLC retention time=3.75 minutes (Waters XBridge C18 4.6×50 mm) eluting with 5-95% aqueous AcCN with 0.05% TFA over a 5.3 minute gradient. LC/MS: m/e 544.07, 545.97 (M+H)+.

Provenance & Evidence