PROCESS FOR PREPARING NEW INTER-M-PHENYLENE-PROSTACYCLIN DERIVATIVES

New inter-m-phenylene-PGI2 derivatives are prepared of the general formula I (I) wherein R1 stands for hydrogen, alkyl containing 1 to 4 carbon atoms or a pharmaceutically acceptable primary, secondary, tertiary or quaternary ammonium cation or a metal cation, R2 and R3 stand independently on each other for hydrogen, alkanoly, aroyl or an acetal type or alkyl silyl type protecting group, R4 represents hydrogen or an alkyl group containing 1 to 4 carbon atoms, X stands for oxygen, or a-CH2-group, Y stands for-C 3BOND C- or a trans-CH=CW group, wherein W stands for chlorine, bromine or fluorine, Z represents an alkyl group having 6 to 9 carbon atoms, optionally substituted by one or more alkyl groups containing 1 to 4 carbon atoms or fluorine or it stands for an optionally substituted arylmethyl or aryloxy methyl group. The new compounds are active ingredients of pharmaceutical compositions having antiaggregatory activity.