Heterocyclic system.<b>XI</b>. Synthesis of 1<i>H</i>,4<i>H</i>-pyrazolo[4,3-<i>b</i>]pyrrolizine and 2<i>H</i>,4<i>H</i>-pyrazolo[4,3-<i>b</i>]pyrrolizine derivatives
Cyclization of pyrrolidinocarboxamide derivatives of 1-phenyl-5-(1H-pyrrol-1-yl)-1H-pyrazole-4-carboxylic acid and 2-phenyl-3-(1H-pyrrol-1-yl)-1H-pyrazole-4-carboxylic acid afforded imminium salts which were transformed into the corresponding ketones. Further reduction of the latter compounds furnished the title derivatives.