Synthesis of single- and double-13C-labeled cholesterol oleate.
Cholesterol oleate with the 13C-label in oleic acid at the carbonyl and/or in the sterol ring at position 4 was synthesized by two methods: (1) cholesterol was condensed with oleic anhydride, prepared from [1-13C] oleic acid, in the presence of dimethylaminopyridine (DMAP) in anhydrous chloroform at room temperature for 4--5 h; (2) cholesterol or 13C-enriched cholesterol at position 4 were reacted with 90% [1-13C]-oleic acid in the presence of dicyclohexylcarbodiimide (DCC) and DMAP at room temperature in anhydrous chloroform for 1.25 h. The single-13C and double-13C-labeled cholesterol oleate were obtained in 90% yields after purification by silicic acid column chromatography. Their purity was assessed by thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC) and 13C-NMR spectroscopy. Tritium-labeled cholesterol oleate was also synthesized by method 1 using the fatty acid anhydride.
Sripada
P K
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Department of Medicine, Boston University School of Medicine, Housman Medical Research Center, MA 02118.
D015761:4-Aminopyridine / Q000031:analogs & derivatives*; D000631:Aminopyridines; D002247:Carbon Isotopes; D002788:Cholesterol Esters / Q000138:chemical synthesis*; D002851:Chromatography, High Pressure Liquid; D004024:Dicyclohexylcarbodiimide; D009682:Magnetic Resonance Spectroscopy
D000631:Aminopyridines; D002247:Carbon Isotopes; D002788:Cholesterol Esters; C014409:cholesteryl oleate; D004024:Dicyclohexylcarbodiimide; D015761:4-Aminopyridine; C003885:4-dimethylaminopyridine