| abstract |
Piperazine compounds of the formula:n wherein R' is aryl;n ar(lower)alkyl which may have lower alkoxy; or heterocyclic(lower)alkyl which may have substituent(s) selected from the group of lower alkyl and aryl on the heterocyclic ring; R 2 is lower alkyl; higher alkyl; lower alkylthio(lower)alkyl; lower alkenylthio(lower)alkyl; hydroxy(lower)alkyl; protected hydroxy(lower)alkyl; amino(lower)alkyl; protected amino(lower) alkyl; carboxy(lower)alkyl; protected carboxy(lower)alkyl; arylthio(lower)alkyl; ar(lower)alkylthio(lower)alkyl; or heterocyclic-(lower)alkyl which may have lower alkyl on the heterocyclic ring; and R 3 and R 4 are each hydrogen or lower alkyl, or pharmaceutically acceptable salt thereof. n Processes for the preparation of these piperazine compounds are also described, together with pharmaceutical compositions comprising them. n The compounds are PAF (Platelet Activating Factor)antagonists and are therefore useful in the prevention and treatment of diseases caused by PAF, such as asthma, thrombosis and nephritis. |