Abstract: Disclosed is an anti-foot-and-mouth disease virus agent for an animal belonging to the Family Suidae, which comprises 3-oxo-3,4-dihyro-2-pyrazincarboxamide or a salt thereof. The agent is extremely useful for the prevention or treatment of food-and-mouth disease in an animal belonging to the Family Suidae. Also disclosed is an anti-foot-and-mouth disease virus agent for sheep, which comprises 3-oxo-3,4-dihyro-2-pyrazincarboxamide or a salt thereof. The agent is extremely useful for the prevention, therapy or the like of food-and-mouth disease in sheep.

Abstract: Disclosed is an anti-foot-and-mouth disease virus agent for an animal belonging to the Family Suidae, which comprises 3-oxo-3,4-dihyro-2-pyrazincarboxamide or a salt thereof. The agent is extremely useful for the prevention or treatment of food-and-mouth disease in an animal belonging to the Family Suidae. Also disclosed is an anti-foot-and-mouth disease virus agent for sheep, which comprises 3-oxo-3,4-dihyro-2-pyrazincarboxamide or a salt thereof. The agent is extremely useful for the prevention, therapy or the like of food-and-mouth disease in sheep.

Abstract: 1

Abstract: Pyrazine derivatives represented by general formula [1]: wherein the variables are as defined in the specification, or salts thereof have an excellent antiviral activity and are useful as a therapeutic agent for treating viral infections. Further, fluoropyrazine-carboxamide derivatives represented by general formula [2]: wherein the variables are as defined in the specification, or salts thereof are useful as an intermediate for production of the compounds of general formula [1], and as an intermediate for production of the fluoropyrazine-carboxamide derivatives of which one typical example is 6-fluoro-3-hyroxy-2-pyrazine-carboxamide having an antiviral activity.

Abstract: Nitrogen-containing heterocyclic carboxamide derivatives represented by the following general formula: wherein ring A is a substituted or unsubstituted pyrazine, pyrimidine, pyridazine or triazine ring; R1 is O or OH; R2 is a hydrogen atom, an acyl group or a substituted or unsubstituted carbamoylalkyl or carboxyalkyl group; and the broken line represents a single bond or a double bond; or salts thereof are useful for preventing and treating virus infections and especially influenza virus infections.

Abstract: Pyrazine derivatives represented by general formula [1]: 1

Abstract: Nitrogen-containing heterocyclic carboxamide derivatives represented by the following general formula: 1

Abstract: The present invention relates to a 2,3-diketopiperazine derivative or a salt thereof, which has inhibitory effect on platelet aggregation because of glycoprotein IIb/IIIa receptor antagonism and hence is useful as a prophylactic and therapeutic agent for diseases associated with platelet aggregation.General formula ##STR1## wherein R.sup.1 represents a protected or unprotected amidino group; R.sup.2 represents a hydrogen atom or a carboxyl-protecting group; A represents a substituted or unsubstituted lower alkylene group; B represents --O--, --CONH--, --NHCO-- or --SO.sub.2 NH--; Y represents a substituted or unsubstituted lower alkylene group; and the broken line represents a single bond or a double bond.

Abstract: The present invention relates to a 2,3-diketopiperazine derivative or a salt thereof, which has inhibitory effect on platelet aggregation because of glycoprotein IIb/IIIa receptor antagonism and hence is useful as a prophylactic and therapeutic agent for diseases associated with platelet aggregation. General formula: ##STR1## wherein R.sup.1 represents a protected or unprotected amidino group; R.sup.2 represents a hydrogen atom or a carboxyl-protecting group; A represents a substituted or unsubstituted lower alkylene group; B represents --O--, --CONH--, --NHCO--or --SO.sub.2 NH--; Y represents a substituted or unsubstituted lower alkylene group; and the broken line represents a single bond or a double bond.

Abstract: Nitrogen-containing heterocyclic carboxamide derivatives represented by the following general formula: wherein ring A is a substituted or unsubstituted pyrazine, pyrimidine, pyridazine or triazine ring; R1 is O or OH; R2 is a hydrogen atom, an acyl group or a substituted or unsubstituted carbamoylalkyl or carboxyalkyl group; and the broken line represents a single bond or a double bond; or salts thereof are useful for preventing and treating virus infections and especially influenza virus infections.