Abstract: A pyrazine derivative of the following formula (I): or a salt thereof. The pyrazine compound (I) and a salt thereof of the present invention are adenosine antagonists and are useful for the prevention and/or treatment of depression, dementia (e.g. Alzheimer's disease, cerebrovascular dementia, dementia accompanying Parkinson's disease, etc.), Parkinson's disease, anxiety, pain, cerebrovascular disease (e.g. stroke, etc.), heart failure and the like.

Abstract: A pyrazine derivative of the following formula (I): or a salt thereof. The pyrazine compound (I) and a salt thereof of the present invention are adenosine antagonists and are useful for the prevention and/or treatment of depression, dementia (e.g. Alzheimer's disease, cerebrovascular dementia, dementia accompanying Parkinson's disease, etc.), Parkinson's disease, anxiety, pain, cerebrovascular disease (e.g. stroke, etc.), heart failure and the like.

Abstract: An aminopyrimidine compound of the following formula (I) wherein Q is (a) or (b) in which R and R? are each optionally substituted aryl or heterocyclic group,R5 is hydrogen, halogen, lower alkyl,optionally substituted hydroxy, optionally substituted amino which may form N-containing heterocyclic group, optionally substituted mercapto, lower alkylsulfinyl or lower alkylsulfonyl, and X is oxygen or sulfur; R1 is hydrogen, optionally substituted lower alkyl or cyclo(lower) alkyl which may be interrupted by an oxygen atom; R2 and R3 are each independently hydrogen, lower alkyl, acyl, aryl or heterocyclic(lower)alkyl, R2 and R3 may be combined together with N atom to which they are attached to form N-containing heterocyclic group; or a salt thereof. The aminopyrimidine compound (I) and salt thereof of the present invention are adenosine antagonists and are useful for the prevention and/or treatment of depression, dementia (e.g.

Abstract: A process for producing a compound of the general formula: ##STR1## wherein R.sup.1 is heterocyclic(lower)alkyl, R.sup.2 is acyl, andR.sup.3 is carboxy(lower)alkyl or protected carboxy(lower)alkyl,which is useful as a medicament or a salt thereof.

Abstract: A process for producing a compound of the general formula: ##STR1## wherein R.sup.1 is heterocyclic(lower)alkyl,R.sup.2 is acyl, andR.sup.3 is carboxy(lower)alkyl orprotected carboxy (lower) alkyl, which is useful as a medicament or a salt thereof.

Abstract: This invention relates to novel peptides, of pharmacological activity, of the formula: ##STR1## wherein R.sup.1 is heptanoyl, stearoyl, 2-hydroxypropionyl or 2-acetoxypropionyl,R.sup.2 is hydrogen or methyl,R.sup.3 is carboxy, benzyloxycarbonyl or hydroxymethyl,R.sup.4 is hydrogen or methyl,R.sup.5 is carboxy or hydroxymethyl,R.sup.6 is carboxy, methoxycarbonyl, 3-t-butoxycarbonylcarbazoyl or hydroxymethyl,R.sup.7 is hydrogen, 3-t-butoxycarbonyl or benzyloxycarbonyl, andn is an integer 0 or 1, with the proviso that when each of R.sup.3 and R.sup.6 is not simultaneously hydroxymethyl, then R.sup.5 is hydroxymethyl.

Abstract: The invention deals with novel peptides useful for the therapeutic treatment of infectious diseases caused by pathogenic microorganisms, having the structure: ##STR1## wherein R.sup.1 is hydrogen, substituted or unsubstituted alkanoyl, or substituted or unsubstituted aralkanoyl,R.sup.2 is carboxy or protected carboxy,R.sup.3 is carboxy, protected carboxy, carbamoyl, or carboxy or protected carboxy(lower)alkylcarbamoyl,R.sup.4 is carboxy, protected carboxy or carbamoyl, andR.sup.5 is hydrogen or an amino protective group, with proviso that at least one of R.sup.3 and R.sup.4 is always carbamoyl and their pharmaceutically acceptable salts.

Abstract: The invention deals with novel peptides useful in the therapeutic treatment of infectious diseases caused by pathogenic microorganisms having the structure: ##STR1## wherein, R.sup.1 is hydrogen or acyl,R.sup.2 is lower alkyl,R.sup.3 is carboxy or protected carboxy,R.sup.4 is hydrogen or lower alkyl,R.sup.5 is hydrogen, alkyl or ar(lower)alkyl,R.sup.6 is carboxy or protected carboxy, andR.sup.7 is hydrogen or an amino protective group,and their pharmaceutically acceptable salts.

Abstract: The invention deals with novel peptides useful for the therapeutic treatment of infectious diseases caused by pathogenic microorganisms, having the structure ##STR1## wherein R.sup.1 is substituted or unsubstituted lower alkanoyl, or substituted or unsubstituted aralkanoyl,R.sup.2 and R.sup.3 are each carboxy or protected carboxy,R.sup.4 is hydrogen or an amino protective group, andR.sup.5 is hydrogen or lower alkyl, and their pharmaceutically acceptable salts.