Disclosed herein are novel prostaglandin I.sub.2 (PGI.sub.2) derivatives exhibiting excellent physiological activities, said derivatives being represented by the general formula: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are as defined herein.
                            本文披露了显示出优异生理活性的新型
前列腺素I.sub.2 (
PGI.sub.2)衍
生物,该衍
生物由下述通式所表示:##STR1## 其中R.sub.1、R.sub.2和R.sub.3如本文所定义。