Regioselective reactions of 1,2-dehydroprogesterone: Syntheses of pregnane derivatives as possible contragestational agents
作者:Dibyendu De、Manju Seth、Amiya Prasad Bhaduri
DOI:10.1016/0039-128x(91)90081-6
日期:1991.4
Reaction of 1 with triethylorthoformate in the presence of boron trifluoride etherate involved the participation of C-21, and the carbonyl at C-3 remained unaffected. The product 13 was identified as 21-[2-hydroxyvinyl]-21-norpregna-1,4-diene-3,20-dione. Reductive amination with sodium cyanoborohydride in the presence of ammonium acetate did not attack ring A and smoothly furnished the amine 14 which
从1,2-脱氢孕酮(1)合成了一些孕烷衍生物。在不影响C-20的情况下将1,2-脱氢孕酮的环A芳香化,水解后得到的乙酰氧基化合物(2)产生1-羟基-4-甲基-19-降冰片烯1,3,5(10)-三烯- 20一(3)。苯酚(3)与烷基卤的反应产生醚6a-6b和7。在7中用仲胺打开环氧乙烷环,得到氨基醇8a-8b。Friedelcraft 3与马来酸酐和氯乙酰氯的反应分别导致9和10的形成。碱催化的10的闭环反应生成1-乙酰基-12a-甲基-8-氧代-5 [H] -1,2,3,3a,3b,4,8,9,10b,11,12,12a-十二烷基氢环戊(7,8)-菲咯啉(3,4-b)呋喃(11),其与芳族醛区域选择性地反应以提供12a-12b。在三氟化硼醚化物的存在下1与原甲酸三乙酯的反应涉及C-21的参与,并且C-3处的羰基不受影响。产物13被鉴定为21- [2-羟基乙烯基] -21-降冰片烯1,4-二