Conversion of ruscogenin into 1α- and 1β hydroxycholesterol derivatives : Structure elucidation by computer assisted analysis of their lanthanide-induced nmr shifts

摘要: Abstract The chemistry of ruscogenin (1) was studied since its structural features qualify it to serve as a potential starting material for 1-hydroxy vitamin D analogs. Ruscogenin oxidized the 1-oxo-derivative 2 which reduced mixture and 1-epiruscogenin (3). Both 1 3 were converted by Clemmensen reduction respective tetrols 12 21, further triols 15 25 diols 16 24 consecutive treatment with p- toluenesulfonyl chloride LAH. triol diol 20 achieved selective benzoylation positions 3, mesylation position followed LAH reduction. utility shift reagent Eu(dpm)3 determine structures products studied. It shown that shifts induced are characteristic orientation OH groups, can facilitate elucidation hydroxylated steroids.