@article{ddd.uab.cat:216732,
      author = {Oyarce, Jocelyn and Aitken, Vanesa and González, César and
               Ferrer, Karoll and Olea, Andrés F. and Parella Coll, Teodor and
               Espinoza Catalán, Luis},
       title = {Synthesis and structural determination of new brassinosteroid
               24-nor-5α-cholane type analogs},
     journal = {Molecules},
        year = {2019},
      volume = {24},
      number = {24},
       pages = {4612--},
       month = {12},
    abstract = {Natural brassinosteroids possess a 22R, 23R configuration that
               appears essential for biological activity. It is, therefore,
               interesting to elucidate if the activity of brassinosteroids with
               a short side chain depends on the C22 configuration. Herein, we
               describe the synthesis of new brassinosteroids analogs with
               24-norcholane type of side chain and R configuration at C22. The
               initial reaction is the dihydroxylation of a terminal olefin that
               leads to S/R epimers. Three different methods were tested in
               order to evaluate the obtained S/R ratio and the reaction yields.
               The results indicate that Upjohn dihydroxylation is the most
               selective reaction giving a 1.0:0.24 S/R ratio, whereas a
               Sharpless reaction leads to a mixture of 1.0:0.90 S/R with 95%
               yield. Using the latter mixture and following a previous reported
               method, benzoylated derivatives and both S and R brassinosteroids
               analogs were synthesized. All synthesized compounds were
               completely characterized by NMR spectroscopy, and HRMS of new
               compounds are also given. In conclusion, a synthetic route for
               preparation of new analogs of brassinosteroids of 24-norcholane
               type and R configuration at C22 were described. It is expected
               that this will help to elucidate if a configuration at C22 is a
               structural requirement for hormonal growth activity in plants.},
         doi = {10.3390/molecules24244612},
         url = {https://ddd.uab.cat/record/216732},
}