| abstract |
Compounds of formula (I): <IMAGE> (I) wherein R1 and R2 is each -R5, -CH=CH-R5 or -C 3BOND C-R5, wherein R5 is optionally substituted aryl or aromatic heterocyclic; R3 is hydrogen, alkyl, cyano or -R5; X is oxygen or sulfur; A a 1,4-homopiperazin-1,4-diyl; B' is alkylene, carbonyl, thiocarbonyl, sulfinyl or sulfonyl; and R4 is optionally substituted phenyl and pharmaceutically acceptable salts thereof have valuable PAF antagonist activity, and may be prepared by reacting a compound containing the homopiperazine part of the molecule with a compound containing the other part of the molecule. |