title: Synthesis of [3 alpha-3H]7-dehydrocholesterol via stable tritiated 4-phenyl-1,2,4-triazoline-3,5-dione derivative.
abstract: Synthesis of [3 alpha-3H]7-dehydrocholesterol is described via protection of the 5,7-diene system in 7-dehydrocholesterol as the Diels-Alder adduct with 4-phenyl-1,2,4-triazoline-3,5-dione followed by oxidation of the hydroxyl group to give the 3-oxo adduct. Reduction of the keto adduct with [3H]sodium borohydride produced the adduct of [3 alpha-3H]7-dehydrocholesterol from which the radiolabeled sterol was obtained via treatment with lithium aluminum hydride. The advantage of the method is that highly labeled [3 alpha-3H]7-dehydrocholesterol can be prepared. Further, unlike 7-dehydrocholesterol, its adduct with 4-phenyl-1,2,4-triazoline-3,5-dione is stable and can be stored. This allows the preparation of small batches of [3 alpha-3H]7-dehydrocholesterol for immediate use in biological experiments, and losses due to decomposition of excess radiolabeled 7-dehydrocholesterol are minimized.
authors.affiliation: Department of Medicine, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark, USA.
authors.forename: A K
authors.initials: AK
authors.lastname: Batta
authors.forename: G
authors.initials: G
authors.lastname: Salen
authors.forename: G S
authors.initials: GS
authors.lastname: Tint
authors.forename: A
authors.initials: A
authors.lastname: Honda
authors.forename: S
authors.initials: S
authors.lastname: Shefer
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry; D001894:Borohydrides / Q000737:chemistry; D003684:Dehydrocholesterols / Q000138:chemical synthesis*; D007553:Isotope Labeling; D018020:Lithium Compounds / Q000737:chemistry; D010084:Oxidation-Reduction; D014230:Triazoles / Q000737:chemistry*; D014316:Tritium
chemical_list: D017607:Aluminum Compounds; D001894:Borohydrides; D003684:Dehydrocholesterols; D018020:Lithium Compounds; D014230:Triazoles; D014316:Tritium; C053540:4-phenyl-1,2,4-triazoline-3,5-dione; C042073:lithium aluminum hydride; C025364:sodium borohydride; C016705:7-dehydrocholesterol