| abstract |
The present invention relates to a novel pyrido[4,3-d]pyrimidine derivative having the formula (I): <IMAGE> (I) wherein each of R1 and R2, which may be the same or different, is a lower alkyl group; R3 is hydrogen, halogen, hydroxy, amino, hydroxyamino, imino, hydrazino or a lower alkylamino group which may optionally have hydroxy, amino or a lower alkylamino group; and R4 is hydrogen, amino, -NH(-) or a lower alkyl group which may optionally have hydroxy, amino or a lower alkylamino group; and pharmaceutically acceptable salt thereof. These compounds are useful as anti-allergic agents, for example, for the treatment of bronchial asthma, urticaria, allergic rhinitis, allergic dermatoses or allergic conjunctivitis. |