Abstract: The compounds represented by the formula (I), and pharmacologically acceptable salts and solvates thereof are disclosed. The compound is hydrolyzed in organisms into a compound represented by the formula in which W represents a hydrogen atom, and D represents the group —V—(CH2)p—COOR, wherein R represents a hydrogen atom. The compound inhibits the aggregation of platelets via the inhibition of the linkage of the platelet membrane protein GPIIb/IIIa to fibrinogen. wherein A represents CH2 or CO, B represents the group —(CH2)k— or —(CH2)m—CO—, X and Y are different from each other and represent N or CH, W represents an ester moiety which can be removed under the physiological condition, and Z represents the groups (II) or (III): wherein D represents the group —V—(CH2)p—COOR.

Abstract: A .gamma.-diketone compound represented by the following formula (I) and a pharmaceutically acceptable salt and solvate thereof having platelet aggregation inhibitory activity is disclosed: ##STR1## wherein B is --Z--(CH.sub.2).sub.q COOR.sup.

Abstract: A compound represented by the general formula (I) and a pharmaceutically acceptable salt and solvate thereof having an effect for inhibiting the aggregation of platelets is disclosed: ##STR1## wherein A, B and C represent independently CH.sub.2 or C.dbd.O;X and Y are different from each other, and each of them is CH or N;D is --(CH.sub.2).sub.k -- or --(CH.sub.2).sub.m --CO-- where k is an integer of 1 to 4; and m is an integer of 0 to 3;E is the following group (II) or (III): ##STR2## wherein n is an integer of 1 to 3; and Z is --W--(CH.sub.2).sub.p --COOR.sup.3 (wherein W is --O-- or a bond; p is an integer of 1 to 4; and R.sup.3 is hydrogen, lower alkyl or an ester residue which can be removed under physiological conditions); R.sup.1 is hydrogen or lower alkyl; and R.sup.2 is hydrogen atom or lower alkyl.

Abstract: A .gamma.-diketone compound represented by the following formula (I) and a pharmaceutically acceptable salt and solvate thereof having platelet aggregation inhibitory activity is disclosed: ##STR1## wherein B is --Z--(CH.sub.2).sub.q COOR.sup.

Abstract: A compound represented by the general formula (I) and a pharmaceutically acceptable salt and solvate thereof having an effect for inhibiting the agglutination of platelets is disclosed: ##STR1## wherein R.sup.1 represents a group --W--(CH.sub.2).sub.i --COOR.sup.3,R.sup.2 represents a hydrogen atom or a group --W--(CH.sub.2).sub.i --COOR.sup.3 or --OR.sup.4,X represents --CH.dbd. or --N.dbd.,Y represents(i) a group --(CO).sub.k --N(R.sup.5)--Z--, wherein Z represents a bond or a group --(CH.sub.2).sub.m --CO-- or a group --(CH.sub.2).sub.m --CHR.sup.6 --,(ii) a group --(CH.sub.2).sub.m --N(R.sup.5)--(CO).sub.k --, or(iii) a group --(CO).sub.k --Het, wherein Het represents a five- or six-membered heterocyclic ring comprising a nitrogen atom,A represents(i) the following groups (II), (III) or (IV) ##STR2## B represents a bond, C.sub.1-6 alkylene or C.sub.2-6 alkenylen.

Abstract: A compound represented by the general formula (I) and a pharmaceutically acceptable salt and solvate thereof having an effect for inhibiting the agglutination of platelets is disclosed: ##STR1## wherein R.sup.1 represents a group --W--(CH.sub.2).sub.i --COOR.sup.3,R.sup.2 represents a hydrogen atom or a group --W--(CH.sub.2).sub.i --COOR.sup.3 or --OR.sup.4,X represents --CH.dbd. or --N.dbd.,Y represents(i) a group --(CO).sub.k --N(R.sup.5)--Z--, wherein Z represents a bond or a group --(CH.sub.2).sub.m --CO-- or a group --(CH.sub.2).sub.m --CHR.sup.6 --,(ii) a group --(CH.sub.2).sub.m --N(R.sup.5)--(CO).sub.k --, or(iii) a group --(CO).sub.k -Het, wherein Het represents a five- or six-membered heterocyclic ring comprising a nitrogen atom,A represents(i) the following groups (III) or (IV) ##STR2## B represents a bond, C.sub.1-6 alkylene or C.sub.2-6 alkenylen.

Abstract: The invention relates to derivatives of pyrrolidin-2-ylcarbonylheterocyclic compound of the general formula ##STR1## in which R.sup.1 represents C.sub.1-6 alkyl, C.sub.1-20 cycloalkyl, aryl or heteroaryl,R.sup.2 represents a heterocyclic compound selected from the group consisting of 2-thiazole, 2-oxazole, 2-imidazole, 2-pyrrole, 2-thiophene, 2-benzothiazole, 2-benzoxazole, 2-benzimidazole, 2-indole, 2-thiazolo[5,4-b]pyridine, 2-oxazolo[4,5-b]pyridine, 2-imidazo[4,5-b]pyridine, 5-thiazole, 2-thiazoline, 2-pyridine, 3-pyridine, 5-pyrimidine, 2-pyrazine, 2-triazole or 2-pyrazole wherein the heterocyclic compound may be unsubstituted or substituted independently with R.sup.4 or R.sup.5 wherein R.sup.4 and R.sup.5 are H, C.sub.1-5 alkyl, aryl or R.sup.4 and R.sup.

Abstract: New arphamenine-related compounds are now provided, which are represented by the formula ##STR1## wherein R.sub.1 denots a hydrogen atom or an amino-protecting group, R.sub.2 denotes a dimethylpyrimidinyl group, R.sub.3 denotes a hydrogen atom or a hydroxyl group, and R.sub.4 denotes a hydrogen atom or a carboxyl-protecting group. The new arphamenine-related compounds exhibit a carboxypeptidase-inhibitory activity and also an immunopotentiating activity and are useful for potentiating the immune response in a living animal.