(1S,3aS,5aR,5bR,7aR,11aR,11bR,13aR,13bR)-1-isopropyl-5a,5b,8,8,11a-pentamethyl-3a-((tetrahydro-2H-pyran-2-yloxy)methyl)octadecahydro-1H-cyclopenta[a]chrysen-9(5bH)-one   、                                                                                      
甲酸乙酯                                                                                                                                                              在
                                                                                                                                                                                 
sodium methylate                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
苯                                                                                  为溶剂,
                                                                                                                                                    反应 2.0h,
                                                                                                                以96%的产率得到(1S,3aS,5aR,5bR,7aR,11aR,11bR,13aR,13bR)-1-isopropyl-5a,5b,8,8,11a-pentamethyl-9-oxo-3a-((tetrahydro-2H-pyran-2-yloxy)methyl)icosahydro-1H-cyclopenta[a]chrysene-10-carbaldehyde