Piperazine compounds, processes for preparation thereof and medical uses thereof

A piperazine compound represented by the formula ##STR128## wherein R and R' are the same or different and each represents a hydroxy group, a lower alkoxy group, a halogen atom, a hydrogen atom, a di(lower alkyl) hydrogenphosphate residue or a group --OR" (wherein R" is an aralkyl hydrocarbon group, a lower alkoxycarbonyl group, an amino acid residue, a lower alkylcarbonyl group or a lower alkylcarbamoyl group), or R and R' taken together form a methylenedioxy group, Y is --CH.dbd.CH-- or --(CH.sub.2).sub.m -- (wherein m is 0, 1 or 2), and Y.sub.1 is a group represented by the formula (2) ##STR129## (wherein A is --NH-- or --O--, A is a methylene group or a carbonyl group, n is 6 to 20, X is a hydroxy group, a hydrogen atom or a lower alkoxycarbonyl group, and X.sub.1 is a phenyl group which may be substituted with a halogen atom or a hydrogen atom), or a group represented by the formula (3) ##STR130## (wherein X and n are as defined above), provided that when Y is the group of the formula (3), each of R and R' is a hydroxy group;

• or a pharmaceutically acceptable salt thereof.