The Synthesis Of Marine Nature Sterol

The aim of this dissertation is the atom economical and highly efficient synthesis ofâ–³²⁴⁽²⁸⁾-steroid compounds using methyl cholanate as the starting material, which laies a foundation for synthesis of the bioactivity compound 24- methylenecholesterol and the key precursor of polyamine sterol MIS-1437 using hyodeoxycholic acid and chenodeoxycholic acid as the starting material respectively.First of all, cholest-24-ketones were synthesized through the key step of selective isopropylation by isopropyl-grignard reagent added with triethylamine at room temperature in a yield of 73% to 89% using six different methyl cholanates as the starting material.Secondly,â–³²⁴⁽²⁸⁾-steroid compounds were synthesized through wittig reaction in a yield of 81% to 99% from the cholest-24-ketones.Thirdly, 24-methylenecholesterol was synthesized in the total yield of 66% in seven steps using hyodeoxycholic acid as the starting material,â–³5-3β-(tetrahydropyran-2- yloxy)- cholest-24-ketone as the key intermediate and selective isopropylation by isopropyl-grignard reagent added with triethylamine at room temperature as the key step.Finally, the key precursorâ–³²⁴⁽²⁸⁾-5α-7α-benzoate-3-ketone-28-homo cholesterol was synthesized in a total yield of 23% in nine steps using chenodeoxycholic acid. as the starting material, 5β-3α,7α-dipl-methoxyl methylethers cholest-24-ketone as the key intermediate and selective isopropylation by isopropyl-grignard reagent added with triethylamine at room temperature as the key step.In summary, cholest-24-ketone was synthesized in one step from methyl cholanate utilizing the intact side chain of methyl cholanate, and thenâ–³²⁴⁽²⁸⁾-side chain was constructed efficiently and atom economically which laies a foundation of the successful synthesis of 24-methylenecholesterol and the key precursorâ–³²⁴⁽²⁸⁾-5α-7α-benzoate- 3-ketone-28-homo cholesterol.