Racemic or optically-active prostaglandin E.sub.1 is synthesized from racemic or optically-active precursors in good yield at the various steps from 3.alpha.,6,7,7.alpha.-tetrahydro-4-methyl-2-oxo-1.beta.-indaneheptanoic acid methyl ester proceeding through 2.alpha.-(2-carboxyethyl)-3.beta.-hydroxy-5-oxo-1.beta.-cyclopentaneheptan oic acid methyl ester, .delta.-lactone, 5-cyclic ethylene acetal, 2.alpha.-(2-carboxy-2-formylethyl)-3.beta.-hydroxy-5-oxo-1.beta.-cyclopent aneheptanoic acid methyl ester, .delta.-lactone, 5-cyclic ethylene acetal, 2.alpha.-(2-carboxy-2-oxoethyl)-3.beta.-hydroxy-5-oxo-1.beta.-cyclopentane heptanoic acid methyl ester, .delta.-lactone, 5-cyclic ethylene acetal, and 3.beta.-hydroxy-2.alpha.-(3-oxo-1-octenyl)-5-oxo-1.beta.-cyclopentanehepta noic acid methyl ester, 5-cyclic ethylene acetal.
外消旋或光学活性的
前列腺素E.sub.1可以从外消旋或光学活性的前体中,在各个步骤中以良好的产量合成。该合成过程从3.alpha.,6,7,7.alpha.-四氢-4-甲基-2-氧代-1.beta.-
茚烷
庚酸甲酯开始,经过2.alpha.-(2-羧基乙基)-3.beta.-羟基-5-氧代-1.beta.-
环戊烷庚酸甲酯、.delta.-内酯、5-环
乙烯缩醛、2.alpha.-(2-羧基-2-甲酰乙基)-3.beta.-羟基-5-氧代-1.beta.-
环戊烷庚酸甲酯、.delta.-内酯、5-环
乙烯缩醛、2.alpha.-(2-羧基-2-氧代乙基)-3.beta.-羟基-5-氧代-1.beta.-
环戊烷庚酸甲酯、.delta.-内酯、5-环
乙烯缩醛,最终得到3.beta.-羟基-2.alpha.-(3-氧代-1-
辛烯基)-5-氧代-1.beta.-
环戊烷庚酸甲酯、5-环
乙烯缩醛。