Synthesis of New Condensed Systems Based on 6,7-Dimethoxy-1-Carbethoxy-4-Spirosubstituted Dihydroisoquinolines

By reducing the ethylesters of spirocyclopentane- and spirotetrahydropyranesubstituted 6,7-dimethoxy-dihydroisoquinoline-1-carboxylic acids, the corresponding 1-hydroxymethyl tetrahydroisoquinolines were synthesized, which were converted into oxazoloisoquinolines by reaction with formalin. The interaction of the latter with hydrobromic and concentrated hydrochloric acids led to the products of recrystallization of oxazoloisoquinolines into tetrahydropyranoisoquinolines. The corresponding dioxinoisoquinolines were synthesized by the reaction of spiro-substituted 6,7-dihydroxyisoquinoline-1-methanol with dibromoethane.