Patent ID: 8580804

Claim:
A compound having a heterocyclic skeleton, which is represented by the formula (I): wherein R 1 and R 2 are the same or different and each is a lower alkyl group optionally having substituent(s), an aralkyl group optionally having substituent(s) or an aryl group optionally having substituent(s), or R 1 and R 2 in combination form, together with the nitrogen atom they are bonded to, a heterocycle optionally having substituent(s) (the heterocycle is optionally condensed with an aromatic hydrocarbon ring); ring A is a pyrimidin-4-one ring condensed with an aromatic ring optionally having substituent(s); R 3 and R 4 are the same or different and each is a lower alkyl group optionally having substituent(s), a lower alkenyl group optionally having substituent(s), a lower alkynyl group optionally having substituent(s), an aralkyl group optionally having substituent(s) or an aryl group optionally having substituent(s), or R 3 and R 4 in combination form, together with the carbon atoms they are respectively bonded to, a homocycle optionally having substituent(s), or a heterocycle optionally having substituent(s) (the homocycle and heterocycle are optionally condensed with an aromatic hydrocarbon ring); and R 5 and R 6 are the same or different and each is a hydrogen atom or a lower alkyl group optionally having substituent(s), a tautomer thereof or a salt thereof.