Intermediates for synthetic use and processes for producing aminopiperazine derivatives

A process for the preparation of a compound of the formula:

• ##STR12## or a pharmaceutically acceptable salt thereof which comprises reacting a compound of the formula:
• ##STR13## or a pharmaceutically acceptable salt thereof with a compound of the formula:
• R.sup.3 --A--OH
• or its reactive derivative or a pharmaceutically acceptable salt thereof,
• wherein R.sup.2 is cyclo(lower)alkyl, aryl or ar(lower)alkyl, each of which may be substituted with halogen,
• R.sup.3 is lower alkyl, aryl, ar(lower)alkoxy or heterocyclic group, each of which may be substituted with halogen, ##STR14##

A process for the preparation of a compound of the formula:

• ##STR15## or a pharmaceutically acceptable salt thereof, which comprises i) subjecting a compound of the formula:
• ##STR16## to elimination reaction of the benzyloxycarbonyl group to give a compound of the formula:
• ##STR17## or a pharmaceutically acceptable salt thereof and then ii) reacting the compound obtained or the pharmaceutically acceptable salt thereof with a compound of the formula:
• R.sup.3 --A--OH
• or its reactive derivative or a pharmaceutically acceptable salt thereof,
• wherein R.sup.2 is cyclo(lower)alkyl, aryl or ar(lower)alkyl, each of which may be substituted with halogen,
• R.sup.3 is lower alkyl, aryl, ar(lower)alkoxy or heterocyclic group, each of which may be substituted with halogen,
• A is ##STR18## or lower alkylene and Y is ##STR19##