A novel prostaglandin I.sub.2 derivative selected from a prostaglandin I.sub.2 having a halogen atom on the carbon atom corresponding to the 7-position of natural prostaglandin I.sub.2 and having a cycloalkylene group in the .alpha.-chain, and its esters and salts.
从具有卤原子的
前列腺素I.sub.2中选择的一种新型
前列腺素I.sub.2衍
生物,其在对应于天然
前列腺素I.sub.2的7位碳原子上具有卤素原子,并且在α-链中具有环烷基团,以及其酯和盐。