| abstract |
The invention relates to novel compounds of general formula (I) and pharmaceutically acceptable salts thereof, wherein X is H, a halogen, nitro, lower alkyl or lower alkyl substituted by halogen or nitro, aralkyl or alkaryl or substituted aralkyl or alkaryl of from one to ten carbon atoms: R<1>, R<2>, R<3> and R<4> are independently H and furthermore, R<1>, R<2>, R<3>, R<4>, R<6> and R<7> are independently alkyl of from one to ten carbon atoms; R<5> is amino, hydroxy, alkoxy of from one to ten carbon atoms, alkyl amino or dialkylamino of from one to ten carbon atoms; and R<8> is independently H, alkyl of from one to ten carbon atoms, carboxyl, alkoxy carbonyl of from one to ten carbon atoms, amino carbonyl, alkylamino carbonyl and dialkylamino carbonyl of from one to ten carbon atoms, or any of these R<8> constituents being aryl substituted thereon. The compounds and pharmaceutical compositions thereof are useful in the analgesic methods of the invention. |