Purine histamine H1 antagonists, their preparation and pharmaceutical compositions containing them.

摘要

The invention concerns histamine H1-receptor antagonists of the formula: <CHEM> where R<1> is hydrogen or alkyl; one of R<2> and R<3> is alkyl and the other is <CHEM> where R<4> is pyridin-2-yl, pyridin-4-yl, thienyl, or phenyl, any of which is optionally substituted by a halo, alkyl of 1 to 6 carbon atoms, nitro, trifluoromethyl, hydroxy or alkoxy of 1 to 6 carbon atoms substituent; and R<5> is pyridin-2-yl, pyridin-4-yl or phenyl, any of which is optionally substituted by a halo, alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 6 carbon atoms, nitro or trifluoromethyl substituent.