Synthesis of 3alpha-hydroxy-21-(1'-imidazolyl)-3beta-methoxyl-methyl-5alpha-pregnan-20-one via lithium imidazole with 17alpha-acetylbromopregnanone.
The synthesis of biologically active 3alpha-hydroxyl-21-(1'-imidazolyl)-3beta-methoxymethyl-5alpha-pregnan-20-one was accomplished in six steps. The key steps were the improvement of stereoselectivity for acetyl isomers in C-17 and the introduction of imidazole into the core structure by use of lithium imidazole. This latter key step provided the desired product in 82% yield without the formation of 1,3-disubstituted imidazolium salt as impurity, which is generally observed in traditional method.
Wong
Fung Fuh
FF
Environmental Resource Management Research Center, National Cheng Kung University, No. 500, Sec. 3, An-Ming Rd., Tainan City, Taiwan 709, ROC. wong99@mail.mcku.edu.tw
Chen
Chun-Yen
CY
Chen
Tse-Hsin
TH
Huang
Jiann-Jyh
JJ
Fang
Hsiao-Ping
HP
Yeh
Mou-Yung
MY
D006865:Hydrogenation; D007093:Imidazoles / Q000737:chemistry; D010084:Oxidation-Reduction; D011280:Pregnanolone / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry*; D013696:Temperature
D007093:Imidazoles; C029899:imidazole; D011280:Pregnanolone