Abstract: A compound of the following formula (I): wherein A is a group of the following formula (I-A): wherein X is an oxygen atom or a sulfur atom, R4 is a hydrogen atom, a C1-6 alkyl group, or other, R5 is a hydrogen atom or other; or a heteroaryl group or other optionally substituted with a halogen, a C1-6 alkyl, a C1-6 alkoxy, or other; R1 and R2 are the same or different and are a hydrogen atom, a C1-6 alkyl group or other; R3 is a hydrogen atom, a halogen atom, a C1-6 alkoxy group, or other; Ra and Rb are the same or different and are a hydrogen atom or a C1-6 alkyl group; and n is an integer of 0-5; or a pharmaceutically acceptable acid addition salt thereof, which can selectively act on mitochondrial benzodiazepine receptor and is useful as a medicament for treating/preventing anxiety disorder, depression, epilepsy, dementia, and so on.

Abstract: 2-Aryl-8-oxodihydropurine derivative of the following formula (I): wherein W is H, lower alkyl, halogen, lower alkoxy, amino, mono- or di-lower alkylamino, or substituted or unsubstituted phenyl; X is H, lower alkyl, cycloalkyl-lower alkyl, substituted or unsubstituted phenyl-lower alkyl, lower alkenyl, carbamoyl, di-lower alkylcarbamoyl, or a group of the formula (Q): —CH(R3)CON(R1)(R2); Y is H, lower alkyl, cycloalkyl, cycloalkyl-lower alkyl, lower alkenyl, substituted or unsubstituted phenyl-lower alkyl, or a group of the formula (Q): —CH(R3)CON(R1)(R2); A is substituted or unsubstituted phenyl, or substituted or unsubstituted heteroaryl; provided that when one of X and Y of the above formula (I) is the group of the formula (Q), then the other is the same groups for X or Y as described above except for the group of the formula (Q), or a pharmaceutically acceptable acid addition salt thereof.

Abstract: A 5-substituted-3-oxadiazolyl-1,6-naphthyridin-2(1H)-one derivative of the formula (I): wherein Het is oxadiazolyl, R1 is H, lower alkyl, cyclo-lower alkyl, trifluoromethyl, lower alkenyl, lower alkynyl, lower alkoxy, lower alkoxy-lower alkyl, hydroxy-lower alkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaromatic group, and R2 is H, lower alkyl, cyclo-lower alkyl, cyclo-lower alkylmethyl, lower alkenyl, cyclo-lower alkenyl, lower alkynyl, substituted or unsubstituted aryl, or substituted or unsubstituted hetero-aromatic group, or a pharmaceutically acceptable acid addition salt thereof, which has high selective affinity to benzodiazepine receptor and is useful particularly as a benzodiazepine inverse agonist, for example, as psychoanaleptic drug or a drug for the treatment of dysmnesia in senile dementia or Alzheimer's disease.

Abstract: A 5-substituted-3-oxadiazolyl-1,6-naphthyridin-2(1H)-one derivative of the formula (I): wherein Het is oxadiazolyl, R1 is H, lower alkyl, cyclo-lower alkyl, trifluoromethyl, lower alkenyl, lower alkynyl, lower alkoxy, lower alkoxy-lower alkyl, hydroxy-lower alkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaromatic group, and R2 is H, lower alkyl, cyclo-lower alkyl, cyclo-lower alkylmethyl, lower alkenyl, cyclo-lower alkenyl, lower alkynyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaromatic group, or a pharmaceutically acceptable acid addition salt thereof, which has high selective affinity to benzodiazepine receptor and is useful particularly as a benzodiazepine inverse agonist, for example, as psychoanaleptic drug or a drug for the treatment of dysmnesia in senile dementia or Alzheimer's disease.