title: A new and improved synthesis of 19-iodocholesterol 3-acetate.
abstract: 19-Iodocholesterol 3-acetate (VI) was synthesized in a single step by iodo group substitution for hydroxyl using either one of two different reagents: (1) carbodiimidonium methiodide (VIII) or (2) triphenyl-phosphine/N-iodosuccinimide (IX). The yields were as satisfactory as those obtained from the two step iodide replacement of a 19-hydroxy group via the 19-tosyloxy group. The principal intermediate, 19-hydroxy cholesterol 3-acetate (V), was derived in appreciable quantities, and relatively inexpensively, through the Pb (OCOCH3) 4 photolytic oxidation of the bromohydrin of cholesterol 3-acetate (III) to the epoxide (IV) thence Zn reduction to the 19-hydroxy compound. A specially designed 12 liter flask was of aid in accomplishing the photolysis reaction. Dry column chromatography with the supportive puncture sampling was integral to achieving the good yields and high purity of 19-iodocholesterol (VIII).
mesh_terms: D015071:19-Iodocholesterol / Q000031:analogs & derivatives; D002788:Cholesterol Esters / Q000138:chemical synthesis*; D007457:Iodine Radioisotopes; D007553:Isotope Labeling / Q000379:methods
chemical_list: D002788:Cholesterol Esters; D007457:Iodine Radioisotopes; D015071:19-Iodocholesterol; C017427:19-iodocholesterol 3-acetate